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how to grow skunk



growing skunk



As You probably know Skunks belong to warmth-loving marijuana strain group. However these marvelous plants manage to grow huge outdoors as well. The major factor is the climate You grow in. For growers from colder areas of the world we've prepared a comprehensive indoor marijuana growing guide. We are sure that those of You who have grown marijuana before can find some interesting hints and tips here. Enjoy!

Artificial Light
Sources ( HPS Lamps )
Setting up the Garden

Soil and Containers for it
Pots and Other Containers
Properties of Soil
Preparing Commercial Soils and Mixers
Buying Soil Components
Digging Soil
Growing Methods

Maintaining the Correct Environment
Requirements for Germination
Light Cycle and Distance of Lights from Plants

Gardening Techniques
Supports for Plants
Uniform Growth

Nutrients and fertilizing
Application: fertilizing
Nutrient Deficiencies
Soilless Mixtures

Diseases and Plant Pests
Microbial Diseases
Nutrient Diseases
Plant Pests

Maintenance and Restarting









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Marijuana adapts well to indoor conditions. You can grow it in sunny rooms or with artificial light. The factor limiting the rate of growth indoors is often the amount of light, since it is less a problem to supply the plants with plenty of water, nutrients, and air.

Natural light is free. If feasible to use, natural light eliminates the most expensive components for indoor gardeners: artificial lights and the electricity they use. Window light is the easiest way to grow plants for decorative purposes or for a small crop. On the other hand, a greenhouse, sunporch, or particularly sunny room can support larger plants than most artificial light systems. A sunny porch or roof area enclosed in sheet plastic to form a greenhouse is a simple, inexpensive way to grow pounds of grass.

Cannabis grows into a fully formed bush when it receives a minimum of five hours of sunlight a day. But you can grow good-sized plants of excellent quality with as little as two hours of daily sunlight provided windows are unobstructed by buildings or trees and allow full daylight. Windows facing south usually get the most light, followed by windows facing east and west (north-facing windows seldom get any sun). Use the location with the longest period of sunlight. The corner of a room or alcoves with windows facing in two or three directions are often very bright. Skylights are another good source of bright, unobstructed light.

Some growers supplement natural light with artificial light from incandescent or fluorescent fixtures. This is essential during the winter, when sunlight is weaker than the summer, and in spaces where the plants get little direct sunlight. Artificial lights can also be used to lengthen the natural photoperiod in order to grow plants all year.

The best time to plant using natural light is in late March or April, when the sun's intensity and the number of hours of daylight are increasing. Cleaning windows dramatically increases the amount of light, especially in cities where grime collects quickly. Paint walls adjacent to windows a flat white or cover them and the floor with aluminium foil to reflect light to the plants. Place young plants on shelves, blocks, or tables to bring them up to the light. Position the plants as close to the windows as possible. Insulate germinating plants from freezing winter drafts by stapling clear sheets of polyethylene film to the window frame.

The main problem with marijuana in windows is that it may be seen by unfriendly people. This won't be a problem at first, but when the plants grow larger, they are easily recognized. You could cover the windows with mesh curtains, rice paper, polyethylene plastic or other translucent materials to obscure the plants. A strip covering the lower part of the window may be enough to conceal the plants from outsiders.

Most of you will want the garden completely hidden. Some gardeners opt for closets, basements, attics - even under loft beds. They cover the windows if the garden is visible and grow the plants entirely with artificial light.

The amount of light you provide is what determine the garden's size - the amount of soil, number and eventual size of the plants, and the overall yield. Since light is the factor on which you base the planning of your garden, let's begin with artificial light.



2.2 Fixtures

Florescent light is the most effective and efficient source of artificial light readily available to the home grower. Fluorescent lamps are the long tubes typical of institutional lighting. They require a fixture which contains the lamp sockets and a ballast (transformer) which works on ordinary house current.

Tubes and their fixtures come in length from four inches to 12 feet. The most common and suitable are four- and eight-foot lengths. Smaller tubes emit too little light for vigorous growth; longer tubes are unwieldy and hard to find. The growing area must be large enough to accommodate one or more of these fixtures through a height of at least six feet as the plants grow. Fixtures may hold from one to six tubes and may include a reflector, used for directing more light to the plants. Some fixtures are built with holes in the reflectors in order for heat to escape. They are helpful in areas where heat builds up quickly. You can make reflectors with household materials for fixtures not equipped with reflectors. Try to get fixtures that have tubes spaced apart rather than close together. See 5.5 for further suggestions.

The tubes and their appropriate fixtures are available at several different wattage or outputs. Standard or regular output tubes use about 10 watts for each foot of their length - a four-foot tube has about 40 watts and an eight-foot tube about 80 watts.

High Output (HO) tubes use about 50 percent more watts per length than regular output tubes and emit about 40 percent more light. An eight-foot (HO) runs on 112 to 118 watts. Very High Output (VHO) or Super High Output (SHO) tubes emit about two-and-a-half times the light and use nearly three times the electricity (212 to 218 watts per eight-foot tube).

The amount of light you supply and the length of the tube determine the size of the garden. Marijuana will grow with as little as 10 watts per square foot of growing area, but the more light you give the plants, the faster and larger they will grow. We recommend at least 20 watts per square foot. The minimum-size garden contains a four-foot fixture with two 40-watt tubes, which use a total of 80 watts. Dividing total watts by 20 (watts per square foot) gives 80w divided by 20w/sq. ft=four sq.ft. (an area one by four feet). A four-tube (80 watts each) eight-foot fixture would give: 320w divided by 20w/sq. ft. = 16 sq. ft. or an area the length of the tube and about two feet wide.

VHO and HO tubes in practice don't illuminate as wide an area when the plants are young, because the light source is one or two tubes rather than a bank. Once the plants are growing well and the light system is raised higher, they will illuminate a wider area. Figure about 25 w/(ft*ft) for HO and 35 w/(ft*ft (or foot squared)) for VHO to determine garden size. A two-tube, eight-foot VHO fixture will light an area the length of the tube and one-and-a-half feet wide.

The more light you give the plants, the faster they will grow. Near 50w/sq. ft. a point of diminishing returns is reached, and the yield of the garden is then limited by the space the plants have to grow. For maximum use of electricity and space, about 40w/sq. ft. is the highest advisable. Under this much light the growth rate is incredible. More than one grower has said they can hear the plants growing - the leaves rustle as growth changes their position. In our experience, standard-output tubes can work as well as or better than VHO's if four or more eight-food tubes are used in the garden.

The yield of the garden is difficult to compute because of all the variable that determine growth rate. A conservative estimate for a well-run garden is one ounce of grass (pure smoking material) per square foot of garden every six months.

In commercial grass, the seeds and stems actually make up more of the bulk weight than the usable marijuana.

The grass will be of several grades depending on when and what plant part you harvest. The rough breakdown might be 1/3 equal to Mexican regular, 1/3 considered real good smoke, and the rest prime quality. With good technique, the overall yield and the yield of prime quality can be increased several fold.

2.3 Sources

When sunlight is refracted by raindrops, the light is separated according to wavelengths with the characteristic colours forming a rainbow. Similarly, the white light of electric lights consists of all the colours of the visible spectrum. Electric lights differ in the amount of light they generate in each of the colour bands. This gives them their characteristic colour tone or degree of whiteness.

Plants appear green because they absorb more light near the ends of the visible spectrum (red and blue) and reflect and transmit more light in the middle of the spectrum (green and yellow). The light energy absorbed is used to fuel photosynthesis. Almost any electric light will produce some growth, but for normal development the plants require a combination of red and blue light.

Sunlight has such a high intensity that it can saturate the plants in the blue and red bands, though most of the sun's energy is in the middle of the spectrum. Artificial lights operate at lower intensities; so the best lights for plant growth emit much of their light in the blue and red bands.

Fluorescent Tubes

Several lighting manufacturers make tubes (gro-tubes) the produce much of their light in the critical red and blue bans. (Plant-gro (GE), Gro-Lux (Sylvania), Agro-Lite (Westinghouse), and gro-lum (Norelco) are examples, and they look purple or pink. Vita-lite and Optima (Duro-test) produce a white light with a natural spectrum very similar to daylight. Duro-test blubs are more expensive than other tubes but they last twice as long. {See spectrum for "The action spectra of chlorosynthesis and photosynthesis compared to that of human vision. Adapted from IES Lighting Handbook237"}

Theoretically, these tubes should work better for growing plants than standard lighting tubes. However, some standard or regular fluorescent tubes used for lighting actually work better for growing plants than more expensive natural-spectrum tubes and gro-tubes specifically manufactured for plant growth. The reason is that regular fluorescent produce more light (lumens), and overall lumen output is more important for growth rate than a specific light spectrum. To compensate for their spectrums, use them in combinations of one "blue" fluorescent to each one or two "red" fluorescent (Box B).

Manufacturers use standardized names such as Daylight and Sofwhite to designate a tube that has a certain degree of whiteness. Each name corresponds to a tube that emits light in a particular combination of colour bands. For example, Cool White emits more blue light than other colours and appears blue-white. By combining tubes that emit more blue light with tubes that emit more red light, the tubes complement each other and produce a more natural spectrum for healthy plant growth. More "red light" than "blue light" sources are needed to foster healthy growth, so use two red tubes to each blue tube.

The best combinations are either Warm White or Soft White (red) tubes used with either Cool White or Daylight (blue) tubes. These four tube types are common, much cheaper, and when used in combination, will give you a better return than any of the more expensive gro-tubes or natural-spectrum tubes. Any hardware store carries these common lighting tubes, and the cost may be less than a dollar each.

Do not use tubes with "deluxe" in their designation. They have a more natural spectrum but emit considerably less light. Preferably, buy "Cool White" since it emits 50 percent more light than "Cool White Deluxe."

Incandescents and Flood Lights

The common screw-in incandescent bulb produces light mainly in the longer wavelengths: far-red, red, orange, and yellow. Higher-wattage bulbs produce a broader spectrum of light than lower-wattage bulbs. Incandescents can be used alone to grow marijuana, but the plants will grow slowly and look scraggly and yellow. Incandescents combined with fluorescent work well, but fluorescent are a better source of red light. Fluorescent tubes generate slightly less heat per watt. With incandescents, heat is concentrated in the small bulb area, rather than the length of the tube, and can burn the plants. In addition, incandescents have less than one-third the efficiency of fluorescent in terms of electricity used. If you decide to use incandescents in combination with fluorescent, use two times the wattage of incandescents to blue source fluorescent, that is, two 40-watt Daylight tubes to about three 60-watt incandescents, evenly spacing the red and blue sources.

The common floodlight has a spectrum similar to but somewhat broader than incandescents. Because they cast their light in one direction and operate at higher intensities, these lights work better than incandescents, both as a single source and to supplement natural or fluorescent light.

The best application for floodlights and incandescents is to supplement natural and fluorescent light, especially when the plants get larger and during flowering. Incandescents and floodlights require no special fixtures, although reflectors increase the amount of light the plants receive. These lights are easy to hang or place around the sides of any light system, and their strong red band promotes more growth and good flower development. Some of their energy is in the far-red band. Most purple gro-tubes and white fluorescent are deficient in this band, and addition of a few incandescents make them more effective. Agro-lite and W/S Gro-Lux emit adequate far-red light and need no addition of incandescents.

Several companies make screw-in spotlights specifically for plant growth. Two brand names are Duro-Test and Gro n'Sho. Although they are an improvement over incandescents as a single source, these lights don't perform nearly as well as fluorescent. A 150-watt bulb would grow one plant perhaps four feet tall. Two eight-foot fluorescent tubes (160 watts) will easily grow eight six-foot plants. For supplemental lighting, the incandescents and floodlight work as well and are cheaper.

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HID Lamps. Metal Halide (MH) and Sodium-Vapour Lamps (HPS)

HID's (High-Intensity-Discharge) are the lamps of choice for serious indoor gardeners. HID lamps commonly illuminate streets, parking lots, and sports stadiums, and they emit very intense light and produce more light, more efficiently than fluorescent. All HID's require specific ballasts and fixtures to operate, so purchase complete systems (fixture, ballast, reflector) along with the lamp. High Times and Sinsemilla Tips magazines (p. 332) feature numerous ads by retailers of horticultural HID systems. Contact the advertisers, and they'll send you brochures with enough information to make an informed choice.

Ordinary metal-halides (MH's and HP's) may emit dangerous UV and particle radiation of the bulb envelop breaks, cracks, or develops a small hole. Broken MH bulbs may continue to operate apparently normally, and exposure may cause serious eye or skin injury. Make sure to purchase MH bulbs designed with a safety feature (such as GE Sat-T-Gard or Sylvania Safeline) that causes the bulb to burn out immediately if the outer envelope ruptures. OR purchase fixtures that shield the bulb in protective tempered glass.

HID's come in many sizes, but generally, use only 400 and 1,000 watt sized lamps. The largest size (1,500 watts) is not recommended because of its relatively short bulb life. Sizes less than 400 watts do not return as much marijuana considering set-up costs and ease of operation. The only exceptions are certain "self-contained" mini-units of 150 and 175 watts (see 4.1). These mini-self-contained units have a horizontal fixture and built-in ballast, which is easy to set up. The horizontal fixture directs up to 45 percent more light to the plants than conventional, vertically positioned lamps with reflectors. The intense light encourages excellent growth and bud formation with modest electrical consumption. They are the best overall light system for small, personal gardens such as closet set-ups.

Position 400 watt HID lamps 18 to 30 inches above plant tops, and 1,000 watt lamps 30 to 42 inches above the tops. During flowering, flowers may "run" rather than form in compact buds if lamps are positioned too close to the plant tops, particularly when using HPS's.

Heat is the main problem with HID's, and the room must be well-ventilated. Use exhaust fans to draw heat out of the room. The fan doesn't need to be large, just active enough to create a strong, ventilating draft.

Light Balancers

Sophisticated gardeners use light balancers which employ a small motor to move reflectors and HID lamps held on tracks or mechanical arms slowly across a garden in either a linear or circular pattern . Light balances save considerable power and bulb costs because they dramatically increase the effectively illuminated garden size, while using less the 24 watts per balancer. With the lights moving on a balancer, all of the garden becomes equally illuminated for modest running costs. Instead of adding another 1,000 watt HID, a light balancer increases the garden size without measurably increasing power consumption, an important consideration when electricity consumption or costs are of concern.

With multi-bulb HID gardens, use one MH to each HPS lamp on a light balancer, and hang the lamps about one foot closer to the plant tops than usual. MH's favour blue light, and HPS's produce more orange-red light. By combining the two, the spectrum is more balanced, and you'll get a better return of well-formed buds.

Low Cost HID Systems

By far, the most efficient and effective set-up for a modest artificial light garden is to use fluorescent lamps set on a long photoperiod for germination, growing seedlings or to raise clones; use another room,, or part of the room separated by a light-tight curtain or barrier, for flowering with (HPS) lamps in horizontal reflectors kept on a short photoperiod to induce and promote flowering.

For example, separate and average sized room into two growing areas by hanging an opaque curtain to block light between the two sections. In the smaller area, grow seedling or clones (see 18.5) for two to six weeks under fluorescent set on a constant light. In the larger section, keep HPS lamp(s) on a 12-hour light cycle for flowering. Move larger seedlings under the HPS lamp(s) for about 9 to 15 weeks to initiate and complete flowering. Meanwhile, start more seedling under fluorescent. It's easy to maintain both sections of the room be constantly replenishing either area with new plants. This setup is very productive for a modest investment in both costs and labour - no time or costly light and electricity is wasted on empty space, and you'll find yourself continuously harvesting mature buds.

{A no frills setup with an HID.  Notice that the ballast is insulated from
the floor with pieces of wood; the fixture is supported by rope and not the
electric cord; plastic protects the floor; there is a timer, a reflector, and

Using this setup, the initial long photoperiod and small area necessary for seedlings or clones is illuminated cheaply by fluorescent. Seedlings grow, and cuttings root, better under fluorescent than HPS's. The larger, more costly flowering section is kept under a short photoperiod of 12 hours of daily light and the strong red light is necessary for good flowering.

For example, the whole operation could draw less then 650 watts: 160 watts by four, four-foot fluorescent set on constant light to start the seedlings; one 400 watt HPS set on 12 hours daily light for flowering; two timers and a venting fan for automating the lights and controlling heat. It's possible to harvest four to six, fully mature crops each year, or continuously harvest. (See Mel Frank's new Marijuana Grower's Insider Guide by RED EYE PRESS for much more information on efficient, low cost, indoor systems and greenhouse gardening.)

2.4 Setting up the Garden

Under artificial light, marijuana grows from three to sic feet in three months, so the height of the light must be easy to adjust. Fixtures can be hung from the ceiling, shelves, walls, or from a simple frame constructed for the purpose. If you are hanging the lights from the walls or ceiling, screw hooks directly into a stud. Studs are located in every room corner and are spaced 16, 18 or 24 inches apart. Light can be supported from lathing using wingbolts, but plaster is too weak to hold a fixture unless a wooden strip held by several wingbolts is attached to the walls or ceiling first to distribute the pressure. Then hang the fixture from a hook in the strip. Closets have hooks and shelves or clothes rungs that are usually sturdy enough to support the fixture. People have gardens under loft beds.

Chains are the easiest means of raising and lowering fixtures. Two chains can be suspended from a solid support from above, and attached to an "S" hook at each end of the fixture. Raise the fixture by inching the hooks to higher links on the chain. Or tie rope to the fixture, pass through an eye hook or pulley in the ceiling or frame, and tie-off at a hook or boat cleat anchored in the wall or frame.

You can also hang the lights permanently and lower plants on a shelf or plywood. The shelf could be suspended or lowered by supporting the shelf with progressively smaller block. This arrangement is often used in "growing factories" where plants are rotated to larger gardens and grow for only a few weeks in each space. One garden may have fluorescent for starting plants and another garden for maturing plants under HID's. With HID's and skylights, lowering the plants may be your best option. Use lightweight soil components or hydroponics rather than heavier soil, and the operation is easier.

If you plan to use six or more fluorescent, remove end sockets and ballasts from fixtures. Mount end sockets and tubes on a frame of one-by-twos or plywood. Space sockets so tubes cover the garden evenly (see Figure 37 and 38). This arrangement illuminates the garden more evenly and drastically reduces the suspended weight since ballasts make up most of a fixture's weight. Keep ballasts off floors and away from water. Mount the ballasts on a nearby wall or on a wooden box. Wet ballasts could actually explode, and at best, are electrically dangerous when wet.

Always buy fixtures with reflectors. For HID's, companies make their own reflectors, but the best reflectors are for horizontally positioned lights no matter which company. Horizontal reflectors focus much more usable light than either parabolic or cone reflectors. HPS's can work in any position, but MH lamps are made to work in either a horizontal or vertical position, and you must buy bulbs that correspond with the fixtures.

For fluorescents, you can make an overhead reflector from the cardboard cartons in which tubes and fixtures are packaged. Cut off the end flaps and form the cardboard into a "U". Face inner side with aluminium foil or paint them white. Leave enough space so the foil or cardboard does not contact end sockets. Staple or tape the reflector behind the tubes to the fixture or from to reflect light toward the plants.

Surround all garden with reflective surfaces, but not so tightly that air can't freely circulate. Even in window gardens, reflective sheets set adjacent to the plants make a marked difference in growth. When artificial lights are high, reflectors from the floor on up keep lower branches actively growing. Mylar, with its mirror-finish, is popular for facing walls. A flat white paint (super or decorator white) reflects better than glossy white or aluminium foil. Flat white has about three percent more reflecting capacity than aluminium foil, and reflects light more uniformly. The difference is slight, so use whatever means is most convenient. Paint walls that border the garden a flat white or cover them with aluminium, mylar, or white plasterboard.

Natural-light gardens also benefit from reflectors. Make them out of cardboard painted white or faced with aluminium foil. Once the plants are past the seedling stage, surround them with reflectors; otherwise only one side of the plants will be fully illuminated.

Covering the floor with a plastic dropcloth (about $1 at any hardware store) will protect your floor and your neighbor's ceiling from possible water damage.

Marijuana grows well in a dry atmosphere, but heated or air-conditioned homes are sometimes too dry during germination and early growth. Enclosing the garden in reflectors will contain some of the moisture and insure a healthy humidity. White sheet plastic is available to enclose open gardens. Do not completely enclose the garden. Leave some open spaces at the bottom, top and ends of the garden to allow air to circulate. Air circulation will become more important as the plants grow larger.

Don't rely on training your pets to stay out of the garden. The garden will attract them, and they can easily destroy young plants by chewing on leaves and stems. Soil is more natural to their instincts than the sidewalk or kitty litter. Protect the garden from pets and toddlers; surround it with white plastic or chicken wire. Large plants are more sturdy and animals can do them little harm. The jungle ambience and an occasional leaf are irresistible to most cats, and they'll spend hours in the garden.

2.5 Electricity

For most growers, the amount of electricity used is of little concern. A four-tube, regular-output, eight-foot fixture draws about 320 watts per hour or about the same as a colour TV. The cost increase to your electric bill will be about two to six dollars a month, depending on local rates.

Farmers who devote entire basements or attics to their gardens are sometime restricted by the amount of current they can draw. Older homes or apartments may have only one 15-ampere circuit but more often have two, for 30 amperes total. Newer homes have either 60 or 100 amperes available through four to six circuits. One 15-ampere circuit can safely accommodate three, two-tube VHO fixtures or six tubes for 1,290 watts, or 16 regular-output, eight-foot tubes for about 1,280 watts total. This allows for a 20 percent safety margin of circuit capacity, which is necessary considering heat loss, starting voltages, etc.

In kitchen and basements the circuits may be rated higher, at either 20 or 30 amperes. You can find out the amperage of the circuit by looking at the fuse rating on the face of the fuse. Determine what room or rooms each circuit is feeding by removing the fuse and seeing which outlets are not working. The wattage capacity of any circuit is found by multiplying volts time amps. Standard United States voltage is 110 to 120 volts.

Fluorescent light fixtures are sometimes sold unwired or without a line cord, and the job is left to you. Follow the diagram on the ballast which shows the wires marked by their colour. Simply attach the wires to the sockets as diagrammed. New sockets have small holes which automatically make contact when the bare end of the wire is pushed into them. Older fixtures have sockets with conventional screw terminals.

Indoor gardens may have aluminium foil, chains, reflectors, and wet floors, all of which are good electrical conductors. Coupled with hanging lights, these conditions could lead to dangerous electrical shocks. Never touch a reflector, fixture, or ballast while watering or standing on a damp floor. Eliminate the chance of serious shocks altogether by turning off the lights whenever you work in the garden. An HID ballast on a damp floor is very dangerous. Raise HID ballasts on wood blocks off the floor.

Reduce the risk of dangerous shocks by using fixtures grounded to the power source. A fixture with a three-pronged plug connected to a three-wire outlet is grounded in a properly wired house. You can also ground a fixture by connecting a #12 or #14 gauge wire to any bare metal screw (not an electric terminal) on the fixture housing to the screw that holds the cover plate on the electrical outlet your using.

{With two prong outlets, connect an adaptor plug with a terminal (top left)
or third wire (top right) from the plug to the screw that holds the cover
plate.  This converts two-wire outlets to three wire grounded systems when a
three-wire electric cord is used, an important electrical safeguard which
grounds the light system.}
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3.2 Pots and Other Containers

In its natural state, marijuana may grow an extensive root system - a fibrous network of fine, lateral roots that branch off a main, carrot-shaped tap root. In dry areas, the tap root can grow more than six feet deep in its search for water. In moist areas with fertile soil (such as in potting mixtures), the lateral roots are able to supply water and nutritive needs and the tap root remains small, often only three or four inches long on a seven-foot-tall mature plant.

The purpose of the growing medium is to provide adequate water and nutrients in addition to anchoring the roots, which hold the plant upright. By watering and fertilizing as needed, you could grow a six-foot plant in a four-inch ((Pots are measured by diameter across the top.)) pot or in a three-foot layer of soil over your whole garden; but neither of these extreme procedures is very practical.

Most growers use containers that will hold between two and five gallons of soil. These are a good compromise in terms of weight, space, cost, and labour. They can be moved easily and hold an adequate reservoir of water and nutrients to support a large mature plant.

Some growers use a single large box or several long troughs that hold a six- to 12-inch layer of soil. These have the advantage of minimal restriction of roots and less frequent waterings, but they require more soil and make rotating or moving the plants impractical.

Determine the right size pot to use in your garden by the amount of light per square foot. For a moderately lighted garden (15 to 25 watts per square foot and most window gardens), use one- to three-gallon containers. For gardens with more light energy - over 25 watts per square foot or one-half day or more of sunlight - use three- to eight-gallon containers. The smallest pot we recommend for a full-grown plant is eight inches or one gallon. This is also a good size for starting plants to be transplanted after two months.

Practically any container that can withstand repeated waterings and has a top at least as wide as its base will do. Each pot must have several holes in the bottom to assure drainage. Growers use flower pots, institutional-sized cans and plastic buckets, baskets and small trash cans, milk crates and wooden boxes.

Plastic trash bags are sometimes used when other large containers can't be found. They must be handled carefully, since shifting the soil damages the fragile lateral roots. They are also more difficult to work with when transplanting. However, a roll of trash bags is an available and inexpensive substitute for other large containers. Plastic bags should be double or triple bagged. Small holes should be punched in the bottom to drain excess water. Use masking tape to patch any unwanted tears. The capacity of the bag should be no more than twice as many gallons as the amount of soil used. For example, with four gallons of soil, the bag should be of a five-gallon, but not more than eight-gallon size. Otherwise, it will not form a cylinder, and the bag will remain a shapeless mass.

Use as many pots as can fit in the lighted area to make the most efficient use of space. Many growers prefer to start the plants in smaller pots, transplanting into larger pots when the plants are larger. There are definite advantages to this method in terms of the yield in the garden, given its space and light energy. Seedlings and small plants take up much less space than they will at maturity, so they can be placed closer together. As the plants grow and begin to crowd each other, remove the less vigorous (to smoke, of course) and transplant the rest into larger pots. Start plants which will be transplanted later in four- to eight-inch flower pots, or one-quart to one-gallon tin cans or milk containers. Peat pots or planting pots are made of compressed plant fibre for the purpose of starting young plants. They are available at garden shops and come in several sizes. Use at least a four-inch pot so that the roots are not restricted in early growth. Peat pots are supposed to break down in the soil, but marijuana's delicate lateral roots may not be able to penetrate unless you score or break away the sides while transplanting. Wax paper cup (six to eight ounces), filled with a soil mixture, work as well as peat pots and are cheaper.

3.3 Properties of Soil

The soil or growing medium serves as a source and reservoir for water, air, and nutrients, and to anchor the roots. Since marijuana grows extremely fast, it has higher water and nutritive needs than most plants grown indoors. The success of your garden depends on supplying the plant with a medium that meets its needs without creating toxic conditions in the process.

There is no such thing as the perfect soil for Cannabis. Each variety can grow within a range of soil conditions. For healthy, full, growth, marijuana prefers a medium with good drainage, high in available nutrients, and near a neutral pH (7.0). These conditions result from a complex set of physical, chemical and biological factors. We will refer to them simply as: (1) texture; (2) nutrients; (3) pH.

Most indoor growers prepare the growing medium using commercial potting mixes. These mixes are usually sterilized or pasteurized and have good general soil properties. Since they seldom list the contents, nutrients, or pH, do some simple test of your basic soil whether you buy or dig for it. Then you can adjust the soil to meet the basic requirements of the plant.


The texture of the medium determines its water-holding and draining properties. Marijuana must have a well-drained medium for healthy growth. Soils that hold too much water or hold it unevenly can drown the roots, leading to poor growth or death of the plant. In a well-drained soil the roots are in contact with air as well as water. Soils that have too much clay, or are overly rich in compost or other organic matter, tend to hold too much water and not enough air. This condition worsens in time. This is especially true of the soil in pots.

You can determine the texture of your soil from its appearance and feel. Dry soil should never cake or form crusts. Dry or slightly moist soil that feels light-weight, airy, or spongy when squeezed, and has a lot of fibrous material, will hold a lot of water. Mix it with materials which decrease its water-holding capacity, such as sand, perlite, or even kitty litter.

Wet soil should remain spongy or loose and never sticky. A wetted ball of soil should crumble or separate easily when poked.

Soil that feels heavy and looks dense with fine particulate matter, or is sandy or gritty, will benefit by being loosened and lightened with fibrous materials such as vermiculite, Jiffy Mix, or sometimes sphagnum moss.

Soil Conditioners to Improve Texture

Perlite (expanded sand or volcanic glass) is a practically weightless horticultural substitute for sand. Sand and perlite contribute no nutrients of their own and are near neutral in pH. They hold water, air, and nutrients from the medium on their irregular surfaces and are particularly good at aerating the soil.

Vermiculture (a micaceous material) and sphagnum moss contribute small amounts of their own nutrients and are near neutral in pH. They hold water, air, and nutrients in their fibre and improve the texture of sandy or fast-draining soils. Jiffy Mix, Ortho Mix, or similar mixes are made of ground vermiculite and sphagnum moss, and are fortified with a small amount of all the necessary nutrients. They are available at neutral pH, are good soil conditioners, and are also useful for germinating seeds.

Sphagnum and Peat Moss (certain fibrous plant matter) are sometimes used by growers to improve water holding and texture. Both work well in small amounts (10 to 15 percent of soil mixture). In excess, they tend to make the medium too acidic after a few months of watering. Use vermiculite or Jiffy Mix in preference to sphagnum or peat moss.


Nutrients are essential minerals necessary for plant growth. The major nutrients are nitrogen (N), phosphorus (P), and potassium (K), which correspond to the three numbers, in that order, the appear on fertilizer and manure packages, and that give the percentage of each nutrient in the mix (see section 9).

Marijuana prefers a medium that is high in nitrogen, and mid-range in phosphorus and potassium. Generally, the darker the soil, the more available nutrients it contains. Commercial soils usually contain a good balance of all nutrients and will support healthy growth for a month or two, even in smaller (one gallon) containers. Many growers prefer to enrich their soil by adding sterilized manures, composts, or humus. All of these provide a good balance of the three major nutrients. They also retain water in their fibre. In excess they cause drainage problems, make the medium too acidic, and attract insects and other pests. A good mixture is one part compost or manure to five to eight parts of soil medium. In large pots (four or five gallons), these mixtures might provide all the nutrients the plant will ever need.

The many prepared organic and chemical fertilizers that can be mixed with the soil vary considerably in available nutrients and concentrations. Used in small amounts, they do not appreciably effect the soil texture. Many prepared fertilizers are deficient in one or more of the major nutrients (see Table 14). Mix them together so there is some of each nutrient, or use them with manures, which are complete (contain some of all three major nutrients). When adding fertilizers, remember that organic materials break down at different rates. It is better to use combinations which complement each other, such as poultry manure and cow manure, than to use either fertilizer alone. (See Table 22 in section 13 for a complete list of organic fertilizers.

Table 14 - Prepared Organic fertilizers

Type of             Percentage by weight of    Availability to
fertilizer          N        P2O5     K20      Plant
Blood meal          13        0        0       Rapid/medium
Bone meal            0.5     15        0       Medium/slow
Blood/bone meal      6        7        0       Medium/slow
Cottonseed meal      6        2        1       Slow/medium
Fish meal            8        2        0       Slow/medium
Hoof and bone meal  10        2        0       Slow
Rock phosphate       6       24        0       Slow
Wood ash             0        1.5    3-7       Rapid
Greensand            0        0      2-8       Medium/slow

Chemical fertilizers are made in about every conceivable combination and concentration. Pick one that is complete and where the first number (N) is at least equal if not higher than both P and K. For example, rose foods may be 12-12-12 or 20-20-20, and work very well for marijuana. Others are: Vigoro 18-4-5 and Ortho 12-6-6. The higher the number, the more concentrated the mix is, and consequently, the more nutrients are available.

Don't use fertilizers which come in pellets or capsules, or that are labeled "timed" or "slow release." They do not work as well indoors as do standard organic and chemical fertilizers. Chemical fertilizers seldom list the amount to mix per pot. You can get some idea by the instructions for application per square foot. Use that amount of each one-half cubic foot of soil mixture.

Many growers add no nutrients at this time but rely on watering with soluble fertilizers when they water. These fertilizers and their application are discussed in section 9.


The pH is a convenient measure of the acidity or alkalinity of the soil medium. It is another way of expressing whether the soil is bitter (alkaline) or sour (acid). The pH is measured on a scale of 0 to 14, with 7.0 assigned neutral; below 7.0 is acid and above is alkaline.

You can think of the pH as a measure of the overall chemical charge of the medium. It affects whether nutrients dissolve to forms available to the plant or to forms the plant can't absorb, remaining locked in the soil medium.

Marijuana responds best to a neutral (7.0 pH) medium, although in a fertile, well-drained soil, it will grow well in a range of 6.0 to 8.5. The simplest way to check the pH is with a soil-test kit from a garden shop or nursery. Test kits are chemicals or treated papers - for example, litmus papers or Nitrazine tape - that change colour when mixed with a wet soil sample. The colour is then matched to a colour chart listing the corresponding pH. Nitrazine tape is available, inexpensively, in drug stores. Some meters measure pH, but these are expensive. Agricultural agents, agricultural schools, and local offices of Cooperative Extension will test a soil sample for pH and nutrient content. Occasionally, a garden-shop person will check pH for you or will know the pH of the soils they sell.

Highly alkaline soils are characteristically poor soils that form cakes, crusts, and hardpan. Soil manufacturers don't use them, nor should they be dug for indoor gardens. Alkaline soils are treated with sulfur compounds (e.g., iron sulphate) to lower the pH.

We have never seen commercial soils that were too alkaline for healthy growth, but they are sometimes too acidic. The pH of acid soil is raised by adding lime (calcium-containing) compounds. Liming compounds come in many forms and grades. Some are hydrated lime, limestone, marl, or oyster shells, graded by their particle size or fineness. Use the finest grade available, since it will have more of a neutralizing potential than a coarse grade. You need to use less and are more interested in immediate results than long-term soil improvement. For indoor gardens, use hydrated lime (available in any hardware store) or wood ashes to raise the pH. Hydrated lime is rated over 90 percent for its neutralizing potential. Wood ashes will neutralize soil acids roughly one-half as well as hydrated lime. However, they also contain some nutrients (potassium, phosphorus, magnesium, and micronutrients) and are handy and free.

There is no exact formula we can give you for raising the pH. The pH does not have to be exact; it's and approximation. At low pH it takes less lime to raise the pH one point than it does when the pH is near neutral. Sandy soils need less lime to raise the pH one point than soils high in clay or organic matter. In general, add three cups of hydrated lime or six cups of fine wood ash to every bag (50 pounds or a cubic foot) of soil to raise the pH one point. For soils that test slightly acid (about 6.5), add two cups of lime or four cups of wood ash.

Soil that tested below 6.0 should be retested in about two weeks, after thoroughly mixing and wetting the soil. Repeat the application until the pH is in an acceptable range. Check the pH of plain water to see if it is influencing the tests. Distilled water is neutral, but tap water sometimes has minerals that can change the pH. Hard water is alkaline. sulfurous water and highly chlorinated water are acidic.

If you have already added lime to a soil that now tests from 6.5 to 7.0, don't add more lime trying to reach exactly 7.0. Too much lime will interfere with nutrient uptake, notably of potassium, phosphorus, and magnesium.

General Soil Characteristics

The texture, pH, and available nutrients of the soil are all related. The most important single factor is texture (good drainage). When soil drains poorly, it creates anaerobic (without air) pockets in the soil. Bacteria or microbes that live without air will begin to multiply and displace beneficial microbes that need air to survive. The anaerobic microbes break down organic matter to a finer consistency, and release CO2 and organic acids to the medium. Drainage worsens, the acids lower the pH, and nutrients, even though present, become unavailable to the plant.

The result can be a four-month-old marijuana plant that is only three inches tall, especially if you use high concentrations of manures and composts, peat and sphagnum moss. If your soil lists manures or composts as additives, add no more than 10 percent of these on your own.f

Drainage problems sometimes develop after several months of healthy growth. It is a good idea to add about 20 percent sand or perlite to even a well-drained soil. You can never add too much of these; they con only improve drainage. They dilute the nutritive value of the soil, but you can always water with soluble fertilizers.

Mixtures using many components in combination seem to work particularly well. This may be because, at a micro-level each component presents a slightly different set of physical, chemical and biological factors. What the plant can't take up at one point may be readily available at another.

3.4 Preparing Commercial Soils and Mixes

Garden soils (or loams) and potting mixes are actually two different groups of products, although they are frequently mislabeled. Some companies sell soil in large bags and a potting mixture in smaller bags, while labeling them the same. Soils and potting mixtures are usually manufactured locally, since transportation costs are prohibitive; so they differ in each area.

Texture and Nutrients

Soils and loams are usually topsoil blended with humus or compost for use as a top dressing in gardens, for planting large outdoor containers, or for the soil part of a potting mixture. They may have a tendency to compact under indoor conditions and will benefit from the addition of perlite or vermiculite. Soils and loams usually contain a good supply of nutrients and may support a full-grown plant in a large container. Commercial soils that are heavy generally work better than lightweight soils. Heavy soils usually contain topsoil, in which marijuana grows very well. Lightness indicates more fibrous content.

For example of possible soil mixtures, see Box D. pre?

BOX D Examples of Soil Mixtures* 1. 5 parts soil 2. 8 parts soil 2 parts perlite 3 parts sand 1 part cow manure 1/4 part 10-10-10 chemical fertilizer 3. 5 parts soil 4. 4 parts soil 2 parts perlite 1 part sand 2 parts humus 1 part vermiculite 1/2 part cottonseed meal 2 parts humus 1/2 part poultry manure 5. 3 parts soil 6. 6 parts soil 1 part perlite 2 parts perlite 1 part sand 2 parts vermiculite 2 parts Jiffy Mix 1/2 part poultry manure 1/2 part blood/bone meal 1/2 part cow manure 1/2 part wood ash 1 part wood ash *Almost all fertilizers are acidic, and need to be neutralized by lime. For the above mixtures, or any similar ones, mix in one cup of lime for each five pounds of manure, cottonseed meal, or chemical fertilizer in order to adjust the pH.

Potting mixes are intended to support an average-size house plant in a relatively small pot. They are sometimes manufactured entirely from wood and bark fibre, composts, and soil conditioners. These mixes are made to hold a lot of water and slowly release nutrients over a period of time, which is what most house plants require. For marijuana, these mixes seldom contain enough nutrients to support healthy growth for more than a couple of months. (Their N is usually low, P adequate, and K usually very high.) They work best when sand or perlite is added to improve drainage, and fertilizers are added to offset their low nutrient content.

The pH

Most commercial mixes and soils are between 6.0 and 7.0 in pH, a healthy range for marijuana. If you buy your soil, it will not be too alkaline for healthy growth, but it might be too acidic. You can minimize the chances of getting and acid soil by avoiding soils with "peat" or "sphagnum" in their names. Avoid soils that are prescribed for acid-loving plants such as African violets or azaleas, or for use in terrariums. With common sense, you can buy a soil, add two cups of lime to each large bag, and not have to worry about the pH. However, the surest procedure is to test the pH yourself.

Probably the best way to find the right soil for your garden is to ask long-term growers. They can relate their past experiences with various mixes and blends. Most long-term growers with whom we have talked have tried many of the mixes available in their areas. A reliable, enlightened nurseryperson or plant-shop operator may also be able to give you some advice.

3.5 Buying Soil Components

All the materials discussed here are available at farm and garden stores or nurseries. Many suburban supermarkets sell large bags of soil and humus. Always buy your materials in the largest units possible to reduce the cost.

Large bags of soil and humus come in either 50-pound bags or one- to four-cubic-foot bags. A 50-pound bag fills about six gallons. There are eight gallons to a cubic foot. Perlite is sold in four-cubic-foot bags (thirty-two gallons). Jiffy Mix and vermiculite are sold in four-cubic-foot bags and in 16 pound bags (about 18 gallons). Sand, perlite and vermiculite come in coarse, medium, and fine grades. All grades work well, but if you have a choice, choose coarse. Sand (not beach sand) is an excellent soil conditioner. The only disadvantage is its heavy weight. Buy sand from lumber yards or hardware stores where it is sold for cement work. It will cost from 1/50 to one-half the cost of garden or horticultural sand. Sand from piles at construction sites works very well.

Calculating the Amount of Soil

The maximum amount of soil mixture for any garden can be found by multiplying the capacity of the largest pot you plan to use by the number of pots that you can fit in the garden. In many cases, the actual amount of the mixture used will be somewhat less. Two illustrations follow.

1. A small garden with a two-tube, eight-foot fixture (160W). Using 20 watts per square foot for fast growth gives 160W divided by 20W/sq.ft. + eight sq.ft. The largest pot needed for this system is three gallons, but two gallons would work. You can fit about 10 three gallon pots in eight square feet; so 3 * 10 + 30 gallons of soil mixture are needed (see Box E).

	Examples Showing How Much Soil Material to Buy to Fill
	a Known Number of Unit-Volume Containers

	Example 1.  For a garden eight square feet in size,
	Buy		Component         Which amounts to

	 3 50-lb (6 gal. ea. ) bags of	soil	18 gallons
	 1 cubic foot of	perlite	 8 gallons
	30 lbs of	humus	 3 gallons
	10 lbs of	chicken manure	 2 gallons
			TOTAL	31 gallons

	Example 2.  For a garden 24 square feet in size,
	Buy		Component         Which amounts to

	 4 1-cu. ft. bags of	soil	32 gallons
	 2 1-cu. ft. bags of	perlite	16 gallons
	 1 1-cu. ft. bag of	vermiculite	 8 gallons
	20 pounds of	cow manure	 3 gallons
			cottonseed meal	 2 gallons
			wood ash	 2 gallons
			TOTAL	63 gallons

2. A large garden with two two-tube, eight-foot VHO fixtures (four times 215 watts or 860 total watts) illuminating a garden three by eight feet, or 24 square feet.

860 watts divided by 24 sq. ft. = about 36W/sq. ft.

The largest pot size for this system is about five gallons. About 16 five-gallon containers can fit in 24 square feet; so 16 * 5 + 80 gal. of mixture are needed. But you could start many more plants in smaller containers and transplant when they are root-bound. You do not use more soil by starting in smaller pots, since all soil is reused. In many cases, you actually use much less soil.

In this system you could start and fit about 40 plants in one-gallon pots in 24 square feet. When the plants begin to crowd each other, some are harvested, making room fir the others, which are transplanted to larger pots. In practice, a high-energy system such as this one (36W/sq. ft.) will grow large plants whose size is limited mainly by the space available. Twelve large female plants are about the most you would want in the system during flowering and for final harvest. Sixty gallons of mixture is all that is needed for the seedlings and the mature crop. This is one-fourth less than the original estimate of 80 gallons, and you actually will harvest a lot more grass (see Box E).

Mixing and Potting

Mix your soil in a large basin, barrel, or bathtub. Individual pots are filled with mixtures by using a smaller container to measure out by part or volume.

Perlite, sand, and dry soil can give off clouds of dust. When mixing large amounts of these, wear a breathing mask or handkerchief over your nose and mouth.

To pot any of the mixtures, first cover any large drainage holes with a square of window screen or newspaper to prevent the mixture from running out. Place a layer of sand, perlite, or gravel about one inch deep to insure drainage. Fill the pots with soil mixture to within three-fourths of an inch from the top of the pot. If your mixture contains manures or composts, cover the last inch or two in each pot with the mixture minus the manure and compost. This will prevent flies, gnats, moulds, and other pests from being attracted to the garden. Press spongy soils firmly (not tightly) to allow for more soil in each pot; otherwise, after a period of watering, the soil will settle and the pot will no longer be full.

Some growers add a few brads or nails to each pot to supply the plant with iron, one of the necessary nutrients. Water the pots and allow them to stand for a day or two before planting. As the soil becomes evenly moist, beneficial bacteria begin to grow and nutrients start to dissolve.

3.6 Digging Soil

Most growers prefer to buy their soil, while some prefer to dig it. Marijuana cannot tolerate heavy clays, mucks, or soils that dry to crusts. Choose a soil from a healthy garden or field, or from an area that supports a lush growth of annual weeds.

Fields that support a good crop of alfalfa, corn or other grains will support a good crop of marijuana. Fields with beets, carrots, and sugar cane indicate a well-drained soil, with near neutral pH. Red clover, sweet clover, and bluegrass have soil requirements similar to those of marijuana. Garden soils are usually fertile and well-drained, but often need lime to counteract soil acidity.

Take the topsoil layer that starts about two inches below the surface debris. Good soil will look dark, feel moist, and small clean and earthy. Use all of the topsoil layer that maintains its dark colour and is interlaced with roots. Your hands should be able to easily penetrate the underlying topsoil if the soil is in good condition. When the soil changes colour, or roots no longer apparent, then you are past the fertile topsoil layer. Abundant worm, millipedes, and other small lifeforms are a good indication that the soil is healthy. A rich layer of topsoil collects by walls, fences, and hedges where leaves and debris collect and decay to a rich humus. Sift the soil to remove stones and root clods. Also, shake out the root clods, which are rich in nutrients.

Soil that is dug should be tested the same way as already prescribed. It should be adjusted with at least 30 percent sand or perlite (vermiculite for very sandy soils), since potting will affect the drainage of even well-drained soils. Never use manures or composts that are not completely degraded to a clean-smelling humus.

Soil that is dug must be sterilized to kill weed seeds, insect eggs, and harmful moulds and fungi. Some chemical treatments (e.g. formaldehyde) are mixed with water and poured over the soil to sterilize it. Soil can be sterilized in a pressure cooker at 15 pounds pressure for 15 minutes, or by baking wet soil in a large pot at 200 degrees for 30 to 40 minutes. Be advised that baking soil will release some formidable odors.

3.7 Growing Methods

As we said before, there are probably as many growing methods as there are marijuana growers. These methods are personal preferences or adaptions to fit particular situations; one method is not necessarily better than any other. However, the value of a garden is often based on the amount of high-quality grass it yields. Since indoor gardens are limited in size, you want the plants to quickly fill the garden with lush growth in order to use the garden efficiently. Otherwise, for the first couple of months, the lights are shining on empty space.

Secondly, the possession of small quantities of marijuana will probably be decriminalized nationally within the next few years. decriminalization for personal possession will open the way for decriminalization for cultivation for personal possession. But small quantities are more difficult to define for cultivation than for simple possession, which is done by weight. Several possible ways to limit the amount for cultivation have been raised: by the number of plants, by the area cultivated, or by the number of plants at a particular stage of development. The outcome may determine whether you try to grow the largest plants possible or the most plants possible in a given area.

There are several ways to increase your garden's yield.

	1.  Pinch or cut back the growing shoots when the plants are young.
            This forces each plant to develop several strong growing shoots
            and generally yield large robust plants.
	2.  Plant a number of plant in each pot.
	3.  Start many plants in small pots and transplant the best plants to
            larger pots when the plants crowd each other.
	4.  Use different light systems to grow plants at different growth

Here are some examples of how to carry out each of these four methods.

1. Fill the growing area with large containers (about five gallons each). Start several plants in each pot but thin the seedlings over a period of six weeks to two months, until one plant is left in each pot. During the fourth or fifth week of growth, pinch back the plants to about equal heights. Cut the growing shoot at about the fourth internode. Each plant will develop a sturdy stem which will support four to eight growing stems and will quickly fill any empty space in the garden. The whole garden is the treated like a hedge. After another month or two, you cut back the growing shoots again to have plants of equal heights. Remove the male plants as soon as they begin to release pollen (or before any male flowers open for sinsemilla). This will leave more space and light for the females to develop. By the time females flower, they've been cut back two or three times or more, and form a dense growth of growing shoots that fill the garden with a cubic layer of flowers. Some growers maintain the plants for up to a year before the final harvest.

2. This method also requires large pots. Instead of thinning the seedlings to leave one per pot, leave at least three. After a few months of growth, remove any plants that lag far behind or any plants that show male flowers. The value of this method is that the odds are at least seven to one that any pot will have at least one female plant. 
Most of the plants you'll grow will fill out with branches by four months at the latest. Often the branches develop young seedlings. The plants may begin to look like small Christmas trees by the second to third months of growth. 
Generally, you don't want to have more than three or four plants in a five-gallon container, because growth will be limited by competition for light and space. 

Some varieties never do fill out. The branches remain small, only two to three inches long, and yield very little grass. We've seen plants like this grown from grass from Vietnam, Thailand, Afghanistan, and Africa. These plants are also quite short, being four to six feet tall fully grown. With varieties like this, it is better not to pinch tops, and to start about six plants per square foot of garden space. At harvest, the garden will be crowded with top stems that are laden with flower clusters. 
Of course, you don't know what varieties will look like until you've seen them grow. For most varieties, each plant will need at least one square foot or space at maturity. It is much less common to find varieties that naturally grow small or especially thin, and, therefore, are those of which you would want to plant more than a few per large pot. 
3. Another popular way to grow is to start plants in a large number of small pots. As the plants crowd each other, some are removed and the rest transplanted to larger pots. 
4. To get the most for your investment requires conservation of light and soil. When the plants are young, a large number fit into a small place. Some growers take advantage of this fact by having several light systems, each with plants at different growth stages. The plants are rotated into larger gardens and pots. This method conserves space, materials, and electricity, and yields a harvest every two months. Using this method, "growing factories" turn out a steady supply of potent grass. 


4.2 Requirements for Germination

Before the seed fell, almost all of its water was sapped to prepare the seed for winter. With only the tiny drop that it holds, the embryo lives a life so slow as to be outside of time as we know it. Cannabis seeds need only water to germinate or sprout. The seeds germinate without light and at temperatures low enough to form ice. Higher temperatures hasten germination. Fresh, homegrown Oaxacan seeds germinated in three days at 70F and in eight days at 33F. Temperatures 70 to 90F are best for germination.

Fresh, mature seeds have a high rate of germination (about 90 to 100 percent) and sprout quickly. Usually sprouts appear three to seven days after planting. Older seeds (over a year, depending on storage) have a lower rate of germination and respond slower. They may take up to three weeks to sprout. To get an idea of what to expect from the seeds follow the procedure in 3.1.

Seeds that do sprout will grow normally, no matter how old they are or how long they take to sprout. From any batch of seeds, most of the ones that sprout will do so within two or three days of each other. A few will continue to come up as many as six months later, but the garden should consist of plants that are basically the same age and size. This makes the garden easier to care for.

Choosing Seeds

Different varieties grow at different rates and attain different sizes and shapes. Under artificial lights, gardens plants from one batch of grass require the least attention, because the plants sprout and grow uniformly and can all be tended at the same time. When several varieties are grown together, some plants are taller than others; you must adjust the height of the plants to keep the marijuana equally illuminated. You may also have to water and fertilize the plants on an individual basis. Some growers start at different varieties under separate light systems. On the other hand, planting several varieties offers you a comparison in potency and yield, and a source for hybrids if you want to develop seed. The next time you plant you'll know which seeds gave the best results and what growing methods will work best for you.

There is no strict correlation between the form and height of the plants and seed size, colour, or pattern. However, some large-seeded varieties grow too tall, with long spaces between leaves. Under artificial lights they yield more stems than leaves. If you have a choice between two equally potent grasses, and one has particularly large seeds (3/16 to 1/4 inch), choose the smaller-seeded variety.


The easiest way to start the plants is to sow the seeds directly into the soil. First, wet the soil with a moderate amount of water, enough to wet the soil with a moderate amount of water, enough to get the soil evenly moist without water running out the bottom. This takes about one-half quart of water for one-gallon containers, and about one quart for three-gallon containers. Plant the seeds a quarter- to half-inch deep. The germination rate is lower when they are planted deeper; and if seeds are planted less then one-quarter inch deep, the sprouts may have difficulty anchoring their roots. Plant about six seeds per pot to assure some sprouts in each pot. Gently press each seed into the soil. Cover the seeds with soil and sprinkle lightly with water. Each day, sprinkle or spray the surface with enough water to thoroughly wet the top half-inch of soil, since the seed must be kept moist for germination.

For most people, germinating the seed is easy. Problems with germination come from either too much or too little water. If you saturate the pots with water, and especially if you continue to saturate the pots after the seeds have sprouted, the seedlings may develop stem rot or root problems. When stem rot develops, the base turns brown, and the seedlings fall over, ending the garden. This can also happen if you keep seedlings in germination boxes or terrariums where the humidity is very high. When the humidity is low, the soil surface dries out quickly and the seeds won't germinate. Sprouts that may come up shrivel and dry at the base of the stem and die.

The key to germination is to keep the soil surface moist after first having moistened the whole pot; then, after the first sprouts have been up for a few days, let the surface of the soil dry between waterings. Don't spray the surface any more. Water with medium amounts of water when the soil in the top couple of inches feels dry. For small pots, water seedlings about twice a week. For larger pots, once each week or two may be enough.

Some growers prefer to plant only seeds they know will sprout, especially when planting seeds which have a low viability. Start the seeds in wet towels or a glass of water. Add one teaspoon of liquid bleach (a three-percent solution) to each cup of water. This will prevent fungus from attacking the seeds, which happens when they are soaked for more than three days. Check the seeds each day. Plant when the radical or roots begins to come out from the pointed end of the seed. Cannabis seed is quite small and has only enough stored food for the embryo to anchor its root and raise its cotyledons. The more developed the root is when planted, the less energy it has to anchor itself in the soil. The sprout may die or growth be delayed until the root is established (transplant shock). In Figure 44, the seeds in a circle are all ready to plant. The centre seed will not survive transplanting.

Some growers prefer to start the plants in a germination box. This extra hassle is not necessary. Transplanting seedlings from one medium to another often causes transplant shock. It is best to plant the seeds directly into the soil.

If you use Soilless mixtures, your seedlings should be started in paper cups, peat pots, or other small pots filled with a soil mixture (see "Transplanting" in Chapter 5 {5.3}). This procedure is also helpful if you have the difficulty starting the plants in large containers. Expandable peat pellets also work very well.

The position of the seed in the soil has a slight effect on germination. The root directs its growth in response to gravity, as shown in Figure 45. However, germination is a little faster when the seeds are planted with the pointed end up. The difference is small, and it's not really necessary to position the seeds in the soil.

If a dry atmosphere presents problems, you can create the moist atmosphere of a germination box and still plant directly in the pot. Cover the seeds with transparent plastic cups or glasses, or cover the pot with plastic kitchen wrap. This creates a greenhouse effect and keeps the soil surface moist without watering. Remove all the covers as soon as you see the first sprouts begin to appear; the sprouts will die if the cover is left on.

4.3 Light Cycle and Distance of Lights from Plants

The seed doesn't need light to germinate. The sprout does need light as soon as it breaks through the soil. Most growers turn the light on when they sow the seeds, though, to warm the soil and encourage germination. Lights may also dray the surface of the soil, especially in large pots or with VHO fixtures. If this is a problem during germination, leave the lights off until you see the first sprout breaking through the soil; or hang the lights about 18 inches above the soil, and lower them to six inches as soon as the sprouts appear.

It is important for normal development that the plants receive a regulated day/night cycle. We emphatically recommend that you use an automatic electric timer (about $8). A timer makes gardening much easier, since you don't have to turn the lights on or off each day. The plants won't suffer from irregular hours or your weekend vacations. Set the timer so that the plants get about 16 to 18 hours of light a day, and leave it on this setting until the plants are well grown (three to six months) and you decide to trigger flowering.

During the seedling and vegetative stages of growth, the plants may be subjected to light during their night period. During flowering, however, the night period must be completely dark.

The plants grow more slowly with less than 16 hours of artificial light a day, and they may flowers prematurely. Some growers leave the lights on up to 24 hours. A cycle longer than 18 hours, may increase the growth rate, especially if the plants are not saturated with light. A longer cycle is helpful in small gardens, such as under standard four-foot fixtures.

No matter what the light source, place the lights as close to the tops as possible without burning the plants. Pay no attention to the manufacturer's instructions for the distance of the plants from the lights; these instructions don't apply to a high-energy plant such as Cannabis. With standard-wattage tubes, keep the lights from two to six inches above the plant tops. With VHO tubes, allow four to eight inches. Maintain the lights at these distances throughout the life of the garden. In most cases you will have to raise the lights once or twice a week as the plants grow.

Standard fluorescents don't get hot enough to burn the plants unless they are in direct contact with leaves for several hours. VHO tubes will burn leaves before they touch them. But you do want to keep the lights as close to the plants as possible. This encourages stocky, robust growth. Incandescents and floodlights get very hot; place them at a greater distance from the plants. Test the distance by feeling for heat with your hands. Place the bulb at the distance where you begin to feel its heat. For a 75-watt incandescent lamp, this is about eight inches.

4.4 Water

Water, the fluid of life, makes up more than 80 percent of the weight of the living plant. Within the cells, life processes take place in a water solution. Water also dissolves nutrients in the soil, and this solution is absorbed by the roots. About 99 percent of the water absorbed passes from the roots into the conduits (xylem) of the stem, where it is distributed to the leaves via the xylem of the leaf veins. Transpiration is the evaporation of water from the leaves. The flow of water from the soil, through the plant to the air, is called the transpiration stream. less then one percent of the water absorbed is broken down to provide electrons (usually in the form of hydrogen) which, along with carbon dioxide, are used to form carbohydrates during photosynthesis. The rest of the water is transpired to the air.


Water provides hydrogen for plant growth, and also carries nutrients throughout the plant in the transpiration stream. However, it is not true that the more water given a plant, the faster it will grow. Certainly, if a plant is consistently under-watered, its growth rate slows. However, lack of water does not limit photosynthesis until the soil in the pot is dry and the plant is wilting.

The amount of water, and how often to water, varies with the size of the plants and pots, soil composition, and the temperature, humidity, and circulation of the air, to name a few variables. But watering is pretty much a matter of common sense.

During germination, keep the soil surface moist. But once the seedling are established, let the top layer of soil dry out before watering again. This will eliminate any chance of stem rot. Water around the stems rather than on them. Seedlings are likely to fall over if watered roughly; use a hand sprinkler.

In general, when the soil about two inches deep feels dry, water so that the soil is evenly moist but not so much that water runs out the drainage holes and carries away the soil's nutrients. After a few trials, you will know approximately how much water the pots can hold. Marijuana cannot tolerate a soggy or saturated soil. Plants grown in constantly wet soil are slower-growing, usually less potent, and prone to attack from stem rot.

Over-watering as a common problem; it develops from consistently watering too often. When the plants are small, they transpire much less water. Seedlings in large pots need to be watered much less often than when the plants are large or are in small pots. A large pot that was saturated during germination may hold enough water for the first three weeks of growth. On the other hand, a six-foot plant in a six-inch pot may have to be watered every day. Always water enough to moisten all the soil. Don't just wet the surface layer.

Under-watering is less of a problem, since it is easily recognized. When the soil becomes too dry, the plant wilts. Plant cells are kept rigid by the pressure of their cell contents, which are mostly water. With the water gone, they collapse. First the bottom leaves droop, and the condition quickly works its way up the plant until the top lops over. If this happens, water immediately. Recovery is so fast, you can follow the movement of water up the stem as it fills and brings turgor to the leaves. A plant may survive a wilted condition of several days, but at the very least some leaves will drop.

Don't keep the pots constantly wet, and don't wait until the plant wilts. Let the soil go through a wet and dry cycle, which will aerate the soil and aid nutrient uptake. Most growers find that they need to water about once or twice a week.

When some soils get particularly dry, the water is not absorbed and runs down the sides and out the bottom of the pot. This may be a problem the first time you water the soil, or if you allow the soil to get very dry. To remedy, add a couple of drops of liquid detergent to a gallon of water. Detergent acts as a wetting agent and the water is absorbed more readily. First water each pot with about one cup of the solution. Allow the pots to stand for 15 minutes, then finish watering with the usual amount of pure water.

Use tepid water; it soaks into the soil more easily and will not shock the roots. Try to water during the plant's morning hours. Water from the top of the pot. If you do want to water from the bottom with trays (not recommended), place a layer of pebbles or gravel in the trays to insure drainage. Don't leaves the pots sitting in water until the pot is heavily saturated. The water displaces the soil's oxygen, and the plants grow poorly.

Tap water in some areas highly chlorinated, which does not seem to harm Cannabis; and many fine crops are raised with water straight from the tap. But chlorine could possibly affect the plants indirectly, by killing some beneficial micro-organisms in the soil. Chlorine also makes the water slightly acidic. However, neither effect is likely to be serious. Some growers have asked whether they should use pet-shop preparations that are sold to remove chlorine from water in fish tanks. These preparations generally add sodium, which removes the chlorine by forming sodium chloride (table salt). This solution does not harm the plants, although repeated use may make the soil too saline. Probably the best procedure is to simply allow the water to sit in an open container for a few days. The chlorine is introduced to water as the gas Cl2, which dissipates to the air. The water temperature also reaches a comfortable level for the plants.

Hard (alkaline) water contains a number of minerals (e.g., Ca++, Mg++, K+) which are essentially nutrients to the plants. Water softeners remove these minerals by replacing them with sodium, which forms slightly salty water. It is much better to water with hard water, because artificially softened water may prove harmful after some time. Occasionally, water may be acidic (sulfurous). Counteract this by mixing one teaspoon of hydrated lime per quart water and watering with the solution once a month.

Water and Potency

We've seen no studies that have evaluated potency in relation to water. A few studies have mentioned the fact that plants that received less water were slightly more potent. Water stress has been practiced by several marijuana-growing cultures. In parts of India, watering is kept to a minimum during flowering.

To limit watering, water with the usual amounts but as infrequently as possible. To encourage good growth, yet keep watering to a minimum, wait until the plants are a few months old before you curtail watering. Give the plants their normal water and note the number of days before they begin to wilt. As the plants get larger, the water needs increase, but this generally stabilizes by the time of flowering.

4.5 Air

The properties of the air seldom present any problems for indoor gardeners. The plants grow well under the ordinary conditions that are found in most homes and can withstand extremes that are rarely found indoors. The plants can survive, in fact thrive, in an atmosphere many house plants can't tolerate. For plant growth, the most important properties of the air are temperature, humidity, and composition.

Temperature and Growth Rate

Temperature control should be no problem. The plants can withstand temperatures from freezing to over 100F. Plant growth is closely related to temperature. Marijuana varieties are, in general adapted to warm if not hot climates. Different varieties will reach their maximum rate of photosynthesis at different temperatures. For almost all marijuana varieties, the rate of photosynthesis will increase sharply with increases in temperatures up to about 70F. Some strains reach their peak rate of growth at about &%F. Others, especially from areas near the equator, such as Colombia, may not reach their peak rate until the temperature is about 90F. However, for all varieties, increases in the growth rate will be slight with increased temperatures over 75F. The average temperature for maximum is about 75 to 80F. In other words, normal household temperatures are fine for growing marijuana and no special temperature control is necessary for most gardens.

Don't set up the garden right next to, or in contact with, a heat source such as a radiator or furnace. If the garden is nearby, the plants should do quite well. The plants are most susceptible to cool temperatures during germination and the first few weeks of growth. In basement gardens, the floor temperature is often lower than the air. It is a good idea to raise the pots off the floor with pallets or boxes. The seeds will germinate quicker, and the plants will get off to a faster start.

If heating is necessary, propane catalytic heaters work well, are safe and clean, and increase the carbon-dioxide content of the air. Electric and natural gas heaters also work well. Do not use kerosene or gasoline heaters. They do not burn cleanly, and the pollutants they produce may harm the plants. Any heater that burns a fuel must be clean and in good working order. Otherwise, it may release carbon monoxide, which is more dangerous to you than to the plants.

Temperature and Potency

Since marijuana varieties are most often grown in semi-tropical and tropical areas, the idea that high temperatures are necessary for potent marijuana is firmly entrenched in marijuana lore. This myth, like many others, is slowly disappearing as marijuana farmers and researchers accumulate more experience and knowledge. There are only a few published papers on the effects of temperature on potency. The best study we've seen 19 grew four different varieties in a controlled environment under artificial lights on a 15-hour day-length. Two temperature regimes were used: a "warm" regime, with temperatures of about 73F during the day and 61F at night (about average for most homes); and a "hot" regime, set at 90F daytime and 73F at night. In all four varieties, the concentration of THC and of total cannabinoids was higher under the "warm" regime. For instance, a Nepalese strain was 3.4 times higher in concentration of total cannabinoids, and 4.4 times higher in THC, when grown under the "warm" regime than the same strain grown under the "hot" regime. Although we agree with the findings in principle, these figures are higher than our experience tells us.

Interpretation of the data does show one point clearly. In all four varieties, the amount of THC lost as CBN was higher under the "hot" regime (see Table 16 - currently excluded from this guide), even though the concentration of THC was higher under the "warm" regime.

Another research group in France has looked at the relationship of potency to temperature. The most recent paper 79 compared four temperature regimes, given in descending order of potencies found: 75F day, 75F night (highest potency); 72F day, 54F night; 81F day, 81F night; and 90F day, 54F night (lowest concentration of THC). In each, the day period was 16 hours and the night period eight hours.

Interestingly, this same research group in an earlier paper 20 reported that the concentration of THC was higher for male plants grown at 90-72F then for those grown at 72-54F. For the female plants, the differences in THC concentration were small. The variety used was a propyl variety (type IV) containing about half as much THCV as THC. For both the male and female plants, the concentration of THCV were high under the 90-72F regime.

The simplest interpretation of all these results is that mild temperatures seem to be optimum for potency. Temperatures over 90F or below 60F seem to decrease the concentration of THC and total cannabinoids. Also, at higher temperatures, much more THC will be lost as CBN. And last, propyl varieties may produce less THCV under a cool regime. Bear in mind that none of these papers accounted for all of the many variables that could have affected the findings. For instance, the concentration of THC was 18 times higher at 75-75F than at 90-54F. We've never seen differences of this magnitude, and sampling error undoubtedly influenced the findings.

In terms of growth rate and potency, daily temperatures of about 75F, give or take a few degrees, are roughly optimum. Normal household temperatures are in the low 70's during daytime and the low 60's at night. The heat from a light system will raise the garden's temperature a few degrees. In most gardens temperatures will be near 75F during the day. Night-time temperatures drop about 10 to 15 degrees. When night-time temperatures drop into the 50's or below, set the light cycle to turn on during the early morning, when the temperature will be lowest. In a small room, the light system will generate enough heat to warm the garden without any need for a heater. Whenever you wish to raise the temperature by, say, five or 10 degrees, it is better to add more lights than a heater. The plants will benefit from the additional light, as well as from the heat they generate. And an electric heater, watt for watt, doesn't generate much more heat than a lamp and its fixture.

Composition of the Air

Air provides two essential ingredients for the living plant: oxygen and carbon dioxide. The plant uses oxygen for respiration in the same way we do. The oxygen is used to burn carbohydrates (CH2O) and other food, yielding energy (ATP; see section 4) for the organism, and releasing carbon dioxide and water into the environment.

During photosynthesis, CO2 is used to form carbohydrates. As part of photosynthesis, light energy is used to split water molecules, releasing oxygen into the environment. In plants, the net result from respiration and photosynthesis is that much more oxygen is released than consumed, and more carbon dioxide is consumed than released. The oxygen in the Earth's atmosphere is formed by photosynthetic organisms.

The similarity between plant and animal respiration ends at a cellular level. Plants don't have lungs to move the air. The passage of gases, whether oxygen or carbon dioxide, is primarily a passive process. The gases diffuse through microscopic pores called stomata, found in Cannabis on the undersides of the leaves. The plants can open and close their stomata, allowing moderate control of the flow of air. However, for good exchange of gases, the plants require adequate ventilation for air circulation. {Cannabis is a C3 plant}

Cannabis is not particularly susceptible to a stuffy or stagnant atmosphere. A garden in the corner of a room that is open to the house will be adequately ventilated. Ventilation is not a problem unless the garden is large and fills a quarter or more of the space in a room. Gardens in small, confined spaces such as closets, must be opened daily, preferably for the duration of the light period. Plants growing in a closed closet may do quite well for the first month, but they'll need the door opened as the plants begin to fill the space. The larger the plants get, the greater the need for freely circulating air.

When the weather is mild, an open, but screened, window is the best solution for ventilation. In large indoor gardens where there isn't much air circulation, a small fan is helpful. After germination, make spaces in the surrounding reflectors to allow air to circulate freely. Leave the spaces at the bottom, ends, and the tops of the garden. The higher the temperature or the humidity, the more the plants need good ventilation.


CO2 is a natural, non-poisonous gas present in the atmosphere, which plants absorb and use during photosynthesis to synthesis sugars and organic compounds for energy and growth. Plants can effectively use CO2 up to about .15 percent concentration, about five times the concentration (.03) naturally present in the atmosphere. Increasing the CO2 dramatically increases the growth rate, often up to twice the rate of growth in plants in a natural atmosphere. Supplemental CO2 systems are an inexpensive way serious gardeners dramatically increase a garden's yield. {And decrease fire risk.} {Picture Common emitter systems are safe, inexpensive, easy to setup, and may double the rate of growth in a garden.}

There are two good ways to increase the concentration of CO2. Greenhouse growers use CO2 generators which produce CO2 by burning a clean-burning fuel such as propane or butane. The problems with CO2 generators are that they require a fuel, operate with an open flame, and produce a lot of heat. These are not necessarily problems if the grow room needs to be heated, and if the room is constantly monitored.

For home-growers, the emitter system is more efficient, relatively cheap, safe, and easy to use. Many suppliers who advertise in High Times and Sinsemilla Tips offer complete emitter systems that come with a regulator, solenoid valve, flow-meter, timer, (sometimes distribution tubing), and detailed, yet simple instructions. You must rent compressed CO2 gas tanks from a local compressed gas supplier or beverage company. The setup is not complicated or expensive, and a walk through the Yellow Pages should show several suppliers.

Since the CO2 in the atmosphere is about .03 percent, and the maximum CO2 concentration that your plants use is about .15 to .2 percent, set your emitter system to regulate a concentration of .12 to .17 percent CO2 in the room. Don't worry if you don't understand. All systems are easy to install and come with easily understood instructions.

4.6 Humidity

Marijuana flourishes through a wide range of relative humidity. It can grow in an atmosphere as dry as a desert or as moist as a jungle. Under ordinary household conditions, the humidity will rarely be too extreme for healthy growth. The effects of the humidity on plant growth are closely tied to temperature, win speed, and the moisture of the soil.

The relative humidity affects the rate of the plant's transpiration. With high humidity, water evaporates from the leaves more slowly; transpiration slows, and growth slows also. With low humidity, water evaporates rapidly; the plant may not be able to absorb water fast enough to maintain an equilibrium and will protect itself from dehydration by closing its stomata. This slows the transpiration rate and growth also slows. There is a noticeable slowing of growth because of humidity only when the humidity stays at an extreme (less then 20 percent or over 90 percent).

Cannabis seems to respond best through a range of 40 to 80 percent relative humidity. You should protect the plants from the direct outflow of a heater or air conditioner, both of which give off very dry air. During the first few weeks of growth, the plants are especially susceptible to a dry atmosphere. If this is a problem, loosely enclose the garden with aluminum foil, white sheet plastic, or other materials. This will trap some of the transpired moisture and raise the humidity in the garden. Once the seedlings are growing well, the drier household atmosphere is preferred.

Where the humidity is consistently over 80 percent, the plants may develop stem rot or grow more slowly. Good air circulation from open windows or a small fan is the best solution.

As long as the air is freely circulating, the plants will grow well at higher humidities. Dehumidifiers are expensive (over $100) and an extravagance.

Humidity and Potency

As far as we know, there has been little work done correlating the relative humidity with potency. In the two related cases we've seen, 85, 117 neither study was intended to examine the effects of relative humidity and potency. However, a lower humidity (50 to 70 percent) produced slightly more potent plants than a higher relative humidity (80 percent and over).

A dry atmosphere seems to produce more potent plants. When the humidity is about 50 percent or less, plant development is more compact, and the leaves have thinner blades. When the atmosphere is humid, growth is taller and the leaves luxuriant with wider blades. The advantage to the plant is that wider blades have more surface and hence can transpire more water. The converse is that thinner blades help conserve water. Higher potency may simply be due to less leaf tissue for a given amount of cannabinoids and resin glands.

The temperature also influences the form and size of the leaves. At higher temperatures, the leaves grow closer together; under a cool regime, the leaves are larger, have wider blades, and are spaced farther apart 77. Possibly, cool temperatures yield slightly lower potency for much the same reason that a moist atmosphere does.

However, differences in potency caused by any of the growth factors (light nutrients, water, temperature, humidity, etc.) are small compared to differences caused by the variety (heredity) and full maturation (expression of heredity). For example, the humidity in Jamaica, Colombia, Thailand, and many other countries associated with fine marijuana is relatively high and averages about 80 percent.

However, try to keep the atmosphere dry. The atmosphere in heated or air-conditioned homes is already dry (usually 15 to 40 percent). For this reason, many growers sow so that the plants mature during the winter if the home is heated or in mid-summer if it is air-conditioned. As we mentioned, there should be no need to use dehumidifiers. Good air circulation and raising the temperature to 75 to 80F are the simplest means of dealing with high humidity.


5.2 Thinning

Depending on the viability of the seeds, there should be several plants growing in each pot. Most growers thin to one plant per pot, but the plants don't have to be thinned until they crowd each other and have filled the garden with foliage. The longer you let them grow, the more potent they'll be.

It is virtually impossible to tell the gender of the plants when they are young. The normal ratio of males to females in Cannabis is one to one. Some farmers end up wit more male plants because of their thinning practices. When the plants are less than a month old, the male plants often appear taller and better developed than the females. The male seedling uses more of its energy to develop its aboveground parts than the female. The female devotes more energy to establishing a strong root system. During the first few weeks, don't thin the plants by leaving only the tallest, or you'll wind up with a higher ratio of males. Try to leave seedling that are healthy and vigorous and that are roughly at the same point of development.

To thin your garden, remove any plants with yellow, white, or distorted leaves. Remove the less vigorous and those that lag far behind in development. Cut the unwanted plants near the base; the root system can remain in the pot.

These harvested seedlings will be your first taste of homegrown grass. Usually they produce a mild buzz, but if you separate the growing tips from the large leaves, they may be more potent.

5.3 Transplanting

However you transplant, try to disturb and expose the roots as little as possible. If you transplant carefully, the plants will not exhibit delayed or slowed growth due to transplant shock.

Transplanting Seedlings

When the plants are a week to two weeks old, transplant to any pot that has no plants. First, moisten the soil in the pot from which you will remove the transplant and let is sit for a few minutes. Take a spade or a large spoon, and insert it between the transplant and the plant that will be left to grow. Try to leave at least one inch of space from spoon to stem. Lever the spoon toward the side of the pot, in order to take up a good-size wedge of soil. Place the transplant in a prepared hole at the same depth that it was growing before. Replace the soil in both pots and moisten lightly again to bond the new soil with the original. If you are careful, a wedge of soil can be removed intact. The root system will not be disturbed and the plant will survive with little or no transplant shock. Do not fertilize a transplant for two weeks.

To prevent possible drop-off and wilting from shock, you may want to use Rootone or Transplantone. These safe powders, available at nurseries, contain root-growth hormones and fungicides. They won't be necessary if you transplant carefully.

Transplanting to Large Pots

Transplanting from smaller to larger pots is a simple procedure. The marijuana root system quickly fills small pots. To transplant, moisten the soil and let it sit to become evenly moist. Pick the potted plant up, and, while holding the base of the stem, rap the pot sharply against something solid. You might cover the soil surface with a piece of newspaper or aluminium foil, which makes the job cleaner. When it is done at the right time, the root system, with all the soil adhering, will pop out of the pot intact.

An approximate time guide for transplanting is shown in Table 17(currently excluded from this guide). At these times, give or take a week, the plants should be root-bound and all the soil will adhere to the roots, making the transplanting clean and easy.

If the root system has not filled the pots by this time, wait a few weeks and the process will be easier. If the root system comes out in a small ball and much of the soil is empty of roots, then soil conditions are poor (usually poor drainage and over-watering) or you are transplanting much too seen.

If the root system doesn't easily pop out, run a knife around the sides of the pot. Sometimes the roots stick to the sides, particularly is paper and clay containers. Check to see if the drainage holes are plugged. Plugged holes stop air from displacing the soil, and the vacuum pressure prevents the soil from sliding out of the pot.

	Table 17
	Guide for Transplanting
Transplant				During
Six-ounce cups				Second to third week
Four-inch pots				Third to fourth week
Six-inch pots (half gallon)             Fourth to fifth week
Eight-inch pots (one gallon)            Seventh to eighth week
Two-gallon containers                   About the tenth week

Transplant into a soil mixture that is the same as (or is very like) the one in the original pots. Otherwise, the soils may have different osmotic properties, and the water may not disperse evenly. (This doesn't apply to small pots that are used for germination and are filled with vermiculture, Jiffy Mix, or other mediums.) Don't bury the stem. Keep the stem base at the same depth that it was growing.

Transplanting in Plastic Bags

To transplant plants that are in plastic bags, place the old bag into the larger-size bag. Put some soil mixture underneath, to bring the base of the stem to where the new soil surface will be. Cut the old plastic bag away and fill the side spaces with soil mixture. Two people make the job easier.

5.4 Supports for Plants

Under natural conditions, stems undergo stress from wind, rain, and animals. These stresses, which indoor plants do not ordinarily face, strengthen the stem. Indoor stems grow sturdy enough to support their own weight and not much more. Plant energy is used to produce more light-gathering leaf tissue, rather than wind-resistant stem tissue. Stems remain slender, usually about one-half to three-quarter inches at maturity. Since you are growing the plants for their leaves and flowers, this does not present a problem.

Healthy plants do not ordinarily need support. If many of your plants have weak or spindly stems, there is a deficiency in either light or nutrients (notably potassium). Simply not having enough light will cause the plants to elongate, with sparse foliage and weak growth. Too much red light will cause elongation, too, so make sure you include a strong blue light, if you are using incandescents or floodlights.

Hanging the lights higher than the recommended distances will cause the plants to elongate by rapidly growing up to the lights. Unlike sunlight, the intensity of artificial light diminishes dramatically with the distance from the lights. The plants respond by growing toward the light, seeking the higher intensity.

Under artificial light, some plants may need support during the seedling stage or because of accident. Depending on plant size, use straws, pencils, dowels, or standard plant stakes such as cane sticks. Set them in the soil and affix the stem with string, masking tape, or wire twists such as those that come with plastic trash bags. Do not tie string or wire tightly around the stem; make a loose loop. The stem will grow in girth and can be injured by a tight loop.

Probably the simplest method of support is to take a rigid piece of wire, form a "C" at one end and bend it to a right angle to the stem. Set the straight end in the soil and place the stem inside the "C." Pipe cleaners are ideal for seedlings. With larger plants, straighten a coat hanger and use the same method.

A common practice in greenhouses where tree seedlings are raised is to shake each plant once or twice daily. This practice simulates natural vibrations from the wind, and the plant reacts by increasing the growth around the stem. The stem grows thicker and stronger, and the tree can better fend once it is transplanted. It works the same way with marijuana. A fan blowing on the plants will also work. These practices are useful if you plan to move your plants outdoors. Otherwise, healthy indoor plants that will remain indoors need no special stem strengthening.

5.5 Uniform Growth

The light intensity from artificial lights drops dramatically as the distance from the light source increases. When the plants are not of equal height, the shorter ones receive less light and consequently grow slower than the taller ones. This compounds the situation and, left to themselves, the shorter plants will stop growing and eventually die from lack of light.

It is important to keep all of the plants close to the lights. This encourages stocky, full growth and can make the difference between harvesting stems and harvesting smoking material.

One way to deal with uneven height is to line the plants up to the line of the plant tops. As the plants grow, move them to different spots in the garden to accommodate their different sizes. Or raise the shorter plants up to the lights by placing them on milk crates, tin cans, bricks, etc.

The quality and quantity of light emitted by a fluorescent is strongest in the middle and weaker toward the ends of the tube. Female plants require more light than males. Once the genders of the plants become clear, move the males to the ends of the system, thus leaving the stronger middle light for the females.

5.6 Pruning

Probably the easiest way to deal with uneven growth is to cut back the taller plants to the average height. You may find this emotionally difficult, but pruning will not harm the plant. Cutting off the growing shoot forces the plant to develop its branches. Some growers cut back all of their plants when they are three to four weeks old. Any horizontal space is quickly filled with growing branches and the plants grow full and robust.

The growing shoots are the most potent plant parts until the flowers appear. Generally, the potency increases with growth. By three months' age, most shoots will be high-quality smoke. You can cut shoots at any time; just don't overdo it. Give the plant a chance to grow and fill out to a good size. Severe pruning will slow growth. New growth may be distorted and abnormal, with a drop in potency.

Each time you cat a growing shoot, whether it is the stem tip or a branch tip, two shoots being to grow from the nearest leaf axils. However, don't think that cutting all the growing shoots of a plant twenty times over the course of a season will yield a plant bearing over a million new shoots, or even that the plants will double their size if pruned. Pruning simply allows the plant to develop its branches earlier. The branches present more area to gather light and, hance, can grow to fill a larger space. However, the plant's size is basically determined by the seed's potential within the limitations of the environment.

Cutting the growing shoots or removing some leaves does not harm the plants. Plants are well adapted to the loss of parts to predators, wind, etc., in the natural world. When leaves are damaged or lost, the plant plugs the wound. The leaf isn't replaced or repaired, but new leaves are continually being formed from the growing shoots. The stem, since it connects all parts of the plant, is more important to the plant as a whole. When the stem breaks or creases, it is capable of repair. You can help the plant repair its stem by splinting the wound or somehow propping the stem up straight. Stems take about four or five days to heal.

When you cut the stem or leaves, you may see the plant's sap momentarily spurt before the wound is plugged. The sap contains primarily the products of photosynthesis, in the form of sucrose (table sugar). Smaller amounts of materials associated with the living organism such as minerals, amino acids, and enzymes are also present. In marijuana, the sap is usually colourless, although a bright red colour - it looks like blood - is not uncommon in later life. The red colour is due to haematin compounds and anthocyanin pigments that naturally build up in some varieties. The red colour may also indicate a nutrient deficiency, notably of nitrogen, phosphorus, potassium, or magnesium.

5.7 Training

Plants grow from the tips of their stems and branches. The growing tip (apical meristem) of the plant contains a hormone that acts as a growth inhibitor. This prevents the branches (lateral buds) from growing. The further a branch is from the growing tip, the less effect of the inhibitor. This is why some species of plants form a cone or Christmas-tree shape with the longest branches toward the bottom of the stem. This is also why the branches grow from the top of the plant when the tip is removed. Once the growing tip is removed, the next highest growing shoot(s) becomes the source of the inhibitor. Under artificial light, the bottom branches may not receive enough light to grow even though they are far away from the inhibitor. Usually the longest branches are toward the middle of the plant.

Some growers hate to cut the growing shoots on the main stem, since it forms the largest and most potent buds by harvest. But you can neutralize the effects of the inhibitor, without cutting the growing shoot, by bending the tip. This allows you to control the height of the plants, and forces them to branch. The top two to six inches of the stem are flexible. Bend it in an arc and secure it to the stem with a wire twist or string. Remove the wire twist in a few days so that the growing tip does not break itself as it twists up to the light. Don't bend the stem too far down. Keep it in the strong light or else it will stop growing. If you accidentally break the tip, you can splint it with matchsticks or ice-cream sticks secured with wire twists or tape until it heals.

To develop large, full plants with well-developed branches, secure the growing tip once or twice for a few days while the plants are young (one to three months).

It is possible to train the tip so that the stem will form a series of "S" shapes or even circles. During flowering, train the tips so that they grow horizontally. This method encourages thick, dense growth. The branch tips can also be trained. Keep bending any tips that grow above the others. This creates a garden filled with a cubic layer of vigorous flower clusters rather than a lot of stems.

We want to emphasise that when you get the knack of training the tips, you can more than double the yield of the most potent plant parts.

NUTRIENTS AND fertilizing

6.2 Nutrients

There are about 15 elements known to be essential to plant life. Carbon, hydrogen, and oxygen are absorbed from air and water. The remaining 12 elements are absorbed primarily from the soil, in mineral (inorganic) forms such as NO3- and K+. They constitute a natural part of soil that becomes available to the plant os organic matter decays and soil particles such as sand and clay dissolve.

Soil elements that are necessary for normal growth are called nutrients. The elements nitrogen (N), phosphorous (P), and potassium (K) are considered major nutrients. The three numbers that appear on all fertilizer packages give the available percentage of these three nutrients that the fertilizer contains; and always in the order N-P-K. For example, 10-2-0 means 10 percent N, 2 percent P (actually, 2 percent P2O5), and no K (actually, no K2O). Fertility is often measured by the amounts of major nutrients a soil contains. Relatively large amount of N-P=K are needed for lush growth.

Three other elements - calcium (Ca), sulfur (S), and magnesium (Mg) - are called secondary nutrients. Plants require less of these nutrients, and most cultivable soils contain adequate amounts for good growth.

Six remaining elements are called trace elements or micronutrients. As their name implies, they are needed in very small amounts. Commercial soils contain enough trace elements to sustain normal growth. The trace elements are also present in manures, humus, ash, and limestone.


The amount of nitrogen a soil can supply is the best indication of its fertility. Nitrogen, more than any other soil nutrient, is inextricably linked with the living ecosystem. Nitrogen is continually cycled through living systems: from soil to plants and back to the soil, primarily by the activity of soil microorganisms. Nitrogen is essential to all life. Nitrogen is a key element in the structure of amino acids, the molecules which make up proteins. These, and all other biomolecules, are synthesisd by the plant. Chlorophyll, genetic material (for example, DNA), and numerous enzymes and plant hormones contain nitrogen. Hence, N is necessary for many of the plant's life processes.

Cannabis is a nitrophile, a lover of nitrogen. Given ample N, Cannabis will outgrow practically and plant. Ample nitrogen is associated with fast, lush growth, and the plant requires a steady supply of nitrogen throughout its life. Marijuana's requirements for N are highest during the vegetative growth stages.


P is a constituent of energy-transfer compounds such as NADP and ATP, and molecular complexes such as the genes. The energy compounds are necessary for photosynthesis, respiration, and synthesis of biomolecules. Cannabis takes up large amounts of P during germination and seedling stages. During flowering and seed set, Cannabis' need for phosphorous is also high.


K influences many plant processes, including photosynthesis and respiration, protein synthesis, and the uptake of nutrients. Just as with P, K uptake is highest during the earliest growth stages. K is associated with sturdy stems and resistance to disease in plants.


Ca functions as a coenzyme in the synthesis of fatty compounds and cell membranes, and is necessary for normal mitosis (replication of cells). Plants take up much more Ca than the small amount necessary for normal growth. Ca is not added to soil as a nutrient; is added to adjust the soil's chemistry or pH.


S is a constituent of certain amino acids and proteins. It is an important part of plant vitamins, such as biotin and thiamine, which are necessary for normal respiration and metabolism. (Plants synthesis all vitamins they need.) Most soils suitable for growing marijuana contain plenty of S.


Mg is involved in protein synthesis and metabolism of carbohydrates. Mg is the central element in the structure of chlorophyll molecules and hence has an important role in photosynthesis. Most mineral soils and commercial soils have a good supply of Mg.

Trace Elements

The trace elements (Fe, Mn, Mb, B, Cu, Zn) are particularly important in the coenzymes and catalysts of the plant's biochemistry. Many life processes, particularly the synthesis and degradation of molecules, energy transfer, and transport of compounds within the plant, depend on trace elements. Trace elements are not used in large quantities to spur growth, but are necessary in minute amounts for normal growth. Indoor soils rarely require an addition of trace elements.

All the nutrients are needed for normal growth. However, most of them are supplied by the potting soil. Ca, S, and the trace elements rarely present any problems. For most growers, fertilizing will simply require periodic watering with a complete fertilizer, one that contains N, P, and K.

6.3 Application: fertilizing

To grow to a large size, marijuana requires a steady supply of nutrients. These can be added to the soil before planting or anytime during growth. Bulk fertilizers are added while the soil is mixed, as described in section 6. These include manures, composts, humus, and concentrated fertilizers, such as rose food. Once the plants are growing, never condition or mulch indoor soils with bulk fertilizers. they promote moulds and fungi and attract other pests to the garden. Concentrated fertilizers can damage the plants if they come in direct contact with the stem or roots.

While the plants are growing, nutrients are given in solution; they are dissolved in water, and the plants are watered as usual. Soluble fertilizers can be either organic or inorganic (chemical), and come in a wide range of concentrations and proportions of nutrients. Two organic fertilizers are liquid manure (about 1.5-1.0-1.5) and fish emulsion ((Some fish emulsion may contain whale by-products.)) (about 5-1-1). Chemical fertilizers commonly may have 20-20-20 or 5-10-5, or may contain only one nutrient, such as 16-0-0.

A 10-5-5 fertilizer is 20 percent soluble nutrients and 80 percent inert ingredients. a 30-10-10 has 50 percent available nutrients and 50 percent inert ingredients. There is approximately the same amount of N in one tsp. of 30-10-10 as in three tsps. of 10-5-5.

Actually, you can almost use any fertilizer, but the nitrogen content should be proportionately high, and there should be some P and L also present. For example, a 20-20-20 would work fine, as would a 12-6-6 or a 3-4-3, but not a 2-10-10 or a 5-10-0.

How much fertilizer to use and how often to fertilize depend primarily on the fertility of the soil and the size of the container relative to the size of the plant. Small plants in large pots usually do not need to be fertilized. Even in small pots, most plants do not need to be fertilized for at least the first month.

As the plants grow, they take nutrients from the soil, and these must be replaced to maintain vigorous growth. During the vegetative stage, even plants in large pots generally require some fertilizing, particularly with N.

The rate of growth of indoor plants is usually limited by the amount of light and space, once adequate nutrients are supplied. At this point, an increase in nutrients will not increase growth. Your goal is to supply the plants with their nutritional needs without overfertilizing and thus toxifying the soil.

Most fertilizers are designed for home use and have instructions for fertilizing houseplants. Marijuana is not a houseplant, and it requires more nutrients than houseplants. The extra nutrients that it needs may be supplied by the use of large pots and a fertile soil mixture. In many cases, you will need to fertilize only in the dosages recommended on fertilizer packages for houseplants. For instance, Rapid-Gro (23-19-17) is popular among marijuana growers; use one tablespoon per gallon of water every two weeks.

A typical program for fertilizing might be to fertilize during the fifth week of growth and every two weeks thereafter until flowering. Then discontinue fertilizing (or give at one-half concentration) unless the plants show a definite need for nutrients. It is better to fertilize with a more diluted solution more often than to give concentrated doses at longer intervals. (For instance, if instructions call for one tablespoon of fertilizer per gallon once a month, use one-quarter tablespoon per gallon once a week.)

Make sure that a fertilizer is completely dissolved in the water before you apply it. Put the recommended amount of fertilizer in a clear glass bottle and mix with about one cup of water. Shake vigorously and then allow it to settle. If any particles of fertilizer are not dissolved, shake again before adding the rest of the water. If you have difficulty getting all the fertilizer to dissolve, first add hot top water. If the fertilizer still does not completely dissolve, you should use another fertilizer.

Never fertilize a dry soil or dry Soilless medium. If the medium is dry, first water with about one-half quart of plain water per pot. Let the pots sit for about 15 minutes so that the water is evenly dispersed in the pot. Then fertilize as usual.

It is difficult to give instruction for fertilizing that will cover all garden situations. You want to supply the plant with its nutritive needs, but overfertilizing con toxify the soil. fertilizing according to instructions for houseplants (both in frequency and concentration) should not toxify the soil. However, the plants may sometimes require more frequent or more concentrated fertilizing. A good way to judge the plant's needs is not to fertilize one plant, double the fertilizer of another plant, and give the rest of the plants their normal dose. If the unfertilized plant grows more slowly, or shows symptoms of deficiencies, then probably all the plant are depending on soluble fertilizers and must be fertilized regularly. If the plants receiving the double dose grows faster than the other plants, increase the other plants' supply also. On the other hand, if there is little difference among the plants, then the soil is providing the plants with enough nutrients, and they either should not be fertilized or should be fertilized with a less-concentrated solution.

Because they are grown in a relatively small area, it is easy to overfertilize indoor plants. When plants are vigorous, look healthy, and are growing steadily, don't be anxious to fertilize, particularly if you have already fertilized several times with soluble fertilizers. Slow growth or symptoms of deficiencies clearly indicate the need for fertilizing.


In an effort to do the best for their plants, some people actually do the worst. Overfertilizing puts excessive amounts of nutrients in the soil, causing toxic soil conditions. Excessive amounts of one nutrient can interfere with the uptake of another nutrient, or change normal plant-soil relations. Since it takes time for a build-up to occur high concentrations of nutrients generally encourage excellent growth until the toxic level is reached.

It takes less N than other nutrients to toxify the soil; hence there is less margin for error when using N. Too much N changes the osmotic balance between plant and soil. Instead of water being drawn into the plant, water is drawn away and the plant dehydrates. The leaves feel limp even though the plant is well watered. The plant will soon die. This tips of the leaves die first and very rapidly the leaves change colour, usually to gold, but sometimes to a brown or green-gray. This change in the plants is faster, more dramatic, and more serious than for any kind of nutrient deficiency.

You can save the plants by immediately leaching the pots as soon as the condition is recognized. Place the pots outdoors or in a sink or bathtub. Discard the top inch or two of loose dirt. Run lukewarm water through the soil until a gallon of water for each two gallons of soil has passed through each pot. The leaves recover turgor in one or two days if the treatment works.

Foliar Feeding

Foliar feeding ((Nitrogen fertilizers are usually NO3 (nitrate) or NO2 (nitrite), substances which are also used to preserve food. They have been shown to undergo reactions to form carcinogenic substances (nitrosamines). As with eating food treated with nitrates and nitrites (hot dogs, sandwich meats, etc.), there is a possibility that such substances might be ingested by eating or smoking foliar-fed plants.)) (spraying the leaves with fertilizer) is a good way to give the plants nutrients without building up the amount of soluble substances in the soil. After the first month, foliar feed the plants with, for example, fish emulsion or a chemical fertilizer. Use any fertilizer that states it can be used for foliar feeding even if it says "not recommended for foliar feeding houseplants." Use a fine-mist sprayer, such as a clean Windex or Fantastik bottle. Dilute the fertilizer according to directions (fish emulsion at one tablespoon per gallon) and spray both sides of the leaves. When foliar feeding, you should spray the plants with plain water the next day, to dissolve unabsorbed nutrients and clean the plants.

Foliar spraying is also a good way to treat plants suffering from nutrient deficiencies. Some nutrient deficiencies actually are caused by the soil's chemistry, rather than by the absence of the nutrient in the soil. Addition of the necessary nutrient to the soil may not cure the plants' problem, because the nutrient becomes locked in the soil, or its uptake may be limited by high concentrations of other elements present in the soil. Foliar feeding is direct, and if the plant's deficiency symptoms do not begin to clear up, then the diagnosis is probably incorrect.

6.4 Nutrient Deficiencies

Before Diagnosing

Before you assume the plant has a nutrient deficiency, make sure the problem is not due to other causes. Examine the plant leaves, and along the stem and in the soil.

Even under the best conditions, not all leaves form perfectly or remain perfectly green. Small leaves that grew on the young seedling normally die within a month or two. Under artificial lights, bottom leaves may be shielded from the light, or be too far away from the light to carry on chlorosynthesis. These leaves will gradually turn pale or yellow, and may form brown areas as they die. However, healthy large leaves should remain green at least three to four feet below the plant tops, even on those plants under small light systems. Under low light, the lower-growing shoots as well as the large leaves on the main stem are affected. Some symptoms of nutrient deficiencies begin first at the bottom of the plant, but these symptoms generally affect the lower leaves on the main stem first, and the progress to the leaves on the branches.

Although some deficiency symptoms start on the lower, older leaves, others start at the growing shoots or at the top of the plants. This difference depends on whether or not the nutrient is mobile and can move from the older leaves to the active growing shoot. Deficiency symptoms of mobile nutrients start at the bottom of the plant. Conversely, deficiency symptoms of immobile nutrients first appear on the younger leaves or growing shoots at the top of the plant. N, P, K, Mg, B, and Mb are mobile in the plant. Mn and Zn are less mobile, and Ca, S, Fe, and Cu are generally immobile.

A dry atmosphere or wet soil may cause the blade tips to turn brown. Brown leaf tips also may indicate a nutrient deficiency, but in this case, more tissue will turn brown than just the end tips.

Chlorosis and necrosis are two terms which describe symptoms of disease in plants. Chlorosis means lacking green (chlorophyll). Chlorotic leaves are pale green to yellow or white. Chlorotic leaves often show some recovery after the necessary nutrient is supplied. Necrosis means that the tissue is dead. Dead tissue can be gold, rust, brown, or gray. It is dry and crumbles when squeezed. Necrotic tissue cannot recover.

Symptoms of deficiencies of either N, P, or K have the following in common: all involve some yellowing and necrosis of the lower leaves, and all are accompanied by red/purple colour in stems and petioles. The simplest way to remedy these deficiencies is to fertilize with a complete fertilizer containing nearly equal proportions of three nutrients.


N is the most common deficiency of Cannabis indoors or out. Nitrogen deficiencies may be quite subtle, particularly outdoors, where the soil may continuously provide a small amount of nitrogen. In this case the opt of the plant will appear healthy, and the plant will grow steadily, but at a slow pace. The deficiency becomes more apparent with growth, as more and more of the lower leaves yellow and fall. The first sign is a gradual, uniform yellowing of the large, lower leaves. Once the leaf yellow, necrotic tips and areas form as the leaves dry to a gold or rust colour. In small pots, the whole plant may appear pale (or lime colour) before many bottom leaves are affected to the point that they yellow or die. Symptoms that accompany N deficiency include red stems and petioles, smaller leaves, slow growth, and a smaller, sparse profile. Usually there is a rapid yellowing and loss of the lower leaves that progresses quickly to the top of the plant unless nitrogen is soon added.

Remedy by fertilizing with any soluble N fertilizer or with a complete fertilizer that is high in N. If your diagnosis is correct, some recovery should be visible in three or four days. Pale leaves will regain some colour but not increase in size. New growth will be much more vigorous and new stems and petioles will have normal green colour.

Indoors, you should expect plants to need N fertilization a few times during growth. Once a plant shows N deficiency, you should fertilize regularly to maintain healthy and vigorous growth. fertilize at about one-half the concentration recommended for Soilless mixtures. Increase the treatment only if the plants show symptoms again. Once the plants are flowering, you may choose not to fertilize if the plants are vigorous. They will have enough N to complete flowering and you don't want to chance toxifying the soil at this late date.


P deficiency is not common indoors, but may appear outdoors, particularly in dry, alkaline soils or in depleted soils, or during cool weather. Phosphorus deficiency is characterized by slow and sometimes stunted growth. Leaves overall are smaller and dark green; red colour appears in petioles and stems. The leaves may also develop red or purple colour starting on the veins of the underside of the leaf. Generally the tips of most of the leaf blades on the lower portion of the plant die before the leaves lose colour. Lower leaves slowly turn yellow before they die. Remedy with any soluble P-containing fertilizer. Affected leaves do not show much recovery, but the plant should perk up, and the symptoms do not progress.


K deficiencies sometimes show on indoor plants even when there is apparently enough supplied for normal growth. Often, potassium-deficient plants are the tallest ((Potassium is associated with apical dominance in some plant species.)) and appear to be the most vigorous. Starting on the large lower leaves, the tips of the blades brown and die. Necrotic areas or spots form on the blades, particularly along the margins. Sometimes the leaves are spattered with chlorotic tissue before necrosis develops, and the leaves look pale or yellow. Symptoms may appear on indoor plants grown in a soil rich in organic material. This may be due to high salinity (Na) of some manures or composts used in the soil. Red stems and petioles accompany potassium deficiencies. K deficiencies that could seriously affect your crop rarely occur with indoor soils. However, mild symptoms are quite common. Usually the plants grow very well except for some necrotic spotting or areas on the older leaves. (This condition is primarily and aesthetic problem, and you may choose not to fertilize. See 19.3.)

K deficiencies can be treated with any fertilizer that contains potassium. Wood ashes dissolved in water are a handy source of potassium. Recovery is slow. New growth will not have the red colour, and leaves will stop spotting after a couple of weeks. In a K-deficient soil, much of the added potassium is absorbed by the soil until a chemical balance is reached. Then additional potassium becomes readily available to the plant.


Ca deficiencies are rare and do not occur if you have added any lime compound or wood ash. But calcium is added primarily to regulate soil chemistry and pH. Make sure that you add lime to soil mixtures when adding manures, cottonseed meal, or other acidic bulk fertilizers. An excess of acidic soil additives may create magnesium or iron deficiencies, or very slow, stunted growth. Remedy by adding one teaspoon of dolomitic lime per quart of water until the plants show marked improvement. Periodically fertilize with a complete fertilizer. Foliar feeding is most beneficial until the soil's chemistry reaches a new balance.


S is plentiful in both organic and mineral soils. Liming and good aeration increases S availability. Hence S deficiencies should not occur in soils that are suitable for growing marijuana. However, sulfur deficiencies sometimes can be confused with N deficiencies and may also occur because of an excess of other nutrients in the soil solution. Sulfur-deficiency symptoms usually start at the top of the plant. There is a general yellowing of the new leaves. In pots, the whole plant may lose some green colour. Both sulfur and Mg deficiencies can be treated with the same compound, epsom salts (MgSO4). Epsom salts, or bathing salts are inexpensive and available at drug stores.


Mg deficiencies are fairly common. They frequently occur in Soilless mixtures, since many otherwise all-purpose fertilizers do not contain Mg. Magnesium deficiencies also occur in mixtures that contain very large amounts of Ca or Cl. Symptoms of Mg deficiency occur first on the lower leaves. There is chlorosis of tissue between the veins, which remain green, and starting from the tips the blades die and usually curl upward. Purple colour builds up on stems and petioles.

A plant in a pot may lose much of its colour in a matter of weeks. You may first notice Mg symptoms at the top of the plant. The leaves in the growing shoot are lime-coloured. In extreme cases, all the leaves turn practically white, with green veins. Iron deficiency looks much the same, but a sure indication of Mg deficiency is that a good portion of the leaf blades die and curl. Treat Mg symptoms with one-half teaspoon of epsom salts to each quart of water, and water as usual. The top leaves recover their green colour within four days, and all but the most damaged should recover gradually. Continue to fertilize with epsom salts as needed until the plants are flowering well. If you are using soilless mixtures, include epsom salts regularly with the complete mixture. Because Mg deficiencies may indicate interference from other nutrients, foliar-spray with Mg to check your diagnosis if the plants are not obviously recovering.


Fe deficiency rarely occurs with indoor mixtures. Iron is naturally plentiful in most soils, and is most likely to be deficient when the soil is very acid or alkaline. Under these conditions, which sometimes occur in moist eastern soil outdoors, the iron becomes insoluble. Remedies include adjusting the Ph before planting; addition of rusty water; or driving a nail into the stem. Commercial Fe preparations are also available. If the soil is acidic, use chelated iron, which is available to the plants under acidic conditions.

Symptoms of iron deficiency are usually distinct. Symptoms appear first on the new growing shoots. The leaves are chlorotic between the veins, which remain dark green and stand out as a green network. To distinguish between Mg and Fe deficiencies, check the lower leaves for symptoms. Iron symptoms are usually most prominent on the growing shoots. Mg deficiencies will also show in the lower leaves. If many of the lower leaves have been spotting or dying, the deficiency is probably Mg. Mg deficiencies are much more common than iron deficiencies in marijuana.

Other Trace Elements

The following deficiencies are quite rare. Trace elements are needed in extremely small amounts, and often enough of them are present as impurities in fertilizers and water to allow normal growth. Many houseplant fertilizers contain trace elements. Trace-element deficiencies are more often caused by an extreme pH than by inadequate quantities in the soil. If a deficiency is suspected, foliar-spray with the trace element to remedy deficiencies. Our experience has been that trace-element deficiencies rarely occur indoors. We advise you not to add trace elements to indoor soils, which usually contain large amounts of trace elements already because of the addition of organic matter and liming compounds. It is easy to create toxic conditions by adding trace elements. Manufacturers also recommend using amounts of trace elements that may be too high for indoor gardens; so use them at about one-fourth of the manufacturer's recommended dose if an addition is found to be necessary.


Mn deficiency appears as chlorotic and the necrotic spots of leaf tissue between the veins. They generally appear on the younger leaves, although spots may appear over the whole plant. Manganese deficiencies are not common. Manganese is present in many all-purpose fertilizers. Mn deficiencies may occur if large amounts of Mg are present.


B deficiency may occasionally occur in outdoor soils. The symptoms appear first at the growing shoots, which die and turn brown or gray. The shoots may appear "burned," and if the condition occurs indoors, you might think the lights have burned the plant. A sure sign of boron deficiency is that, once the growing tip dies, the lateral buds will start to grow but will also die. B deficiency can be corrected by application of boric acid, which is sold as an eyewash in any drugstore. Use one-fourth teaspoon per quart of water. Recovery occurs in a few days with healthy growth of new shoots.


Mb deficiency occurs in outdoor soils, but rarely indoors. Mb is readily available at neutral or alkaline pH. Mb is essential for nitrogen metabolism in the plant, and symptoms can be masked for a while when N fertilizers are being used. Usually there is a yellowing of the leaves at the middle of the plant. fertilizing with nitrogen may remedy some of the yellowing. However, Mb symptoms generally progress to the growing shoots and new leaves often are distorted or twisted. Mb is included in many all-purpose fertilizers.


Zn-deficiency symptoms include chlorosis of leaf tissue between the veins. Chlorosis or white areas start at the leaf margins and tips. More definite symptoms are very small, new leaves which may also be twisted or curled radially. Zn deficiencies may occur in alkaline western soils. Galvanized nails can be buried or pushed into the stem. Commercial preparations of zinc are also available.


Cu deficiencies are rare; be careful not to confuse their symptoms with the symptoms of overfertilization. The symptoms appear first on the younger leaves, which become necrotic at the tips and margins. Leaves will appear somewhat limp, and in extreme cases the whole plant will wilt. Treat by foliar-spraying with a commercial fungicide such as CuSO4.

6.5 Soilless Mixtures

Soilless mixtures are an alternative to using large quantities of soil. Their main advantage is complete control over the nutrients that your plants receive. Soilless mixtures are also inexpensive and easy to prepare. They have a near-neutral pH and require no pH adjustment.

Soilless mixtures are made from soil components such as vermiculite, sand, or perlite. Soilless mixtures should be blended in such a way that they hold adequate water, but also drain well and do not become soggy. A good general formula is two parts vermiculite to one part perlite. About 10 percent coarse sand or gravel can be added to give weight and stability to the pots. Instead of vermiculite, you can use Jiffy-Mix, Metro-Mix, Ortho-Mix, Pro-Mix and other commercial soilless mixtures, which are fortified with a small amount of necessary nutrients, including trace elements. You can also substitute coarse sand for perlite.


It is best to use solid containers with soilless mixtures rather than plastic bags. Grow the plants in one- to three-gallon containers. There won't be much difference in the size of the plants in one-gallon or in three-gallon sizes, but you will have to water a large plant every day in a one-gallon container. (The plants can always by transplanted to a larger container.) The pots must have drainage holes punched in the bottoms. Pot as usual, and add one tablespoon of dolomitic lime or two tablespoons of wood ash to each gallon of mixture.


Plants may have problems germinating in soilless mixtures. The top layer of mixture often dries rapidly, and sprouts may die or not germinate. Young seedlings also seem to have difficulty absorbing certain nutrients (notably potassium), even though adequate amounts of nutrients are being added. Since this difficulty may retard growth, it is best to start the plants in small pots with soil. Use eight-ounce paper cups, tin cans, or quart milk containers cut in half. Mix three parts topsoil or potting soil to one part soilless mixture. Fill the starting pots and germinate as usual. When the plants are two to three weeks old, transplant to the soilless mixture. First moisten the soil, and then remove the soil as intact as possible. You might handle the transplant like making castles, by carefully sliding the moist soil out of the pot. Or you can cut away the sides of the container while you place the transplant in the soilless mixture. When watering, make sure you water around the stem to encourage roots to grow into the soilless mixture.

Peat pellets that expand are also good for starting seedling. Plant several seeds in each pellet, and place it in the soilless mixture after the sprouts appear.


Soilless mixtures can be treated with a trace-element solution. We have grown crops with no special addition of trace elements, and the plants completed their lives without showing symptoms of trace-element deficiency. In these cases there were apparently enough trace elements in the lime and the fertilizers that were used to provide the major nutrients. Many all-purpose fertilizers also contain trace elements. However, it is a good idea to treat soilless mixtures with a mild solution of trace elements before planting. Large plants can be treated a second time during the third or fourth month of growth. Do not use trace elements more often unless plants show definite trace-element deficiencies.

Iron is the only trace element that is needed in more than minute quantities. Iron can be supplied by mixing a few brads or nails into the soilless mixture.

Use any soluble fertilizer that is complete, that is, that contains some of each of the major nutrients. Choose one with a formula that is highest in N but contains a good portion of both P and K. For example, Rapid-Gro is 23-19-17 and works well for soilless mixtures.

Table 18 gives a formula that has worked well for us. The figures in it are a guide for estimating the amounts of fertilizer to use. When choosing a fertilizer by means of this chart, use N for a guide. For example, suppose the only fertilizer you can find that has good proportions of the major nutrients as a 20-15-15. Divide 5 (the figure for N in the table) by 20 (the figure for N in the fertilizer), and get the result 1/4. That is, the fertilizer if four times as concentrated in N as you need; so you would use one-fourth the amount of fertilizer shown in Table 18. For instance, during the vegetative stage, you would give the plants one-half to three-fourths of a level teaspoon of fertilizer per gallon of water each time you water.

Table 18 - Guidelines for Fertilizing Soilless Mixtures

Growth Stage  N        P2O5     K20      Amount
Seedling      5        3        4        1.5 to 2 tsp/gal
Vegetative    5        2        3        2 to 3 tsp/gal
Flowering     5        5        3        0.5 tp 1.5 tsp/gal

It is also not necessary to fertilize in these ratios. You could use a 10-10-10 fertilizer throughout growth; you would use half the amounts listed in Table 18. The most important point is that the plant receive enough of each element, not that they receive specific proportions.

fertilizing according to volume of fertilizer is not very accurate, and also does not take into account other variables (such as variety, light, temperature, etc.) that determine the amounts of nutrients your plants can use. However, it is a simple and useful way of estimating the plant's needs. You can more accurately gauge the plants' needs by giving a sample plant twice the concentration of fertilizer, and another half the concentration. Their performance will give you an idea of whether you are using too much or too little fertilizer. Too much fertilizer is the most damaging condition; so when in doubt give the plants less rather then more. Do not continue to give the plants the recommended amounts of fertilizer if the sample plant that is receiving less nutrients is growing as well as the other plants.

Another way of monitoring the plant's growth is to grow a few plants in a standard soil mixture. This will show you whether the plants in the soilless mixture are growing as fast as they should, and will give you a reference for diagnosing deficiencies.

Besides providing N, P, K, and the trace elements, you must also give your plants secondary nutrients. Ca is added by mixing a tablespoon of lime or two tablespoons of wood ash when preparing the soilless mixture. (Calcium is usually present in water and in many fertilizers as part of the salts that contain nutrients, for example, Ca(NO3)2.) Magnesium and sulfur are both found in common epsom salts, MgSO4. Use one-eighth teaspoon of epsom salts to each teaspoon of 5 percent N. For example, if you are using a 20 percent N fertilizer, you would use half a teaspoon of MgSO4 to each teaspoon of fertilizer. (Actually, enough sulfur is often present, either as part of the soilless mixture or as part of nutrient salts to allow growth.) Magnesium can also be supplied by using dolomitic limestone.

Soilless mixtures are something between soil mixtures and water cultures (hydroponics). With hydroponics, the plants are grown in a tank of water. The fertilizers are added in solution, and the water solution is periodically circulated by a pump.

Another variation on soilless mixtures is to add a small amount of soil or humus to the soilless mixture. Some examples are:

        1. 4 parts soilless mixture to 1 part soil;
	2. 8 parts soilless mixture to 1 part humus;
	3. 15 parts soilless mixture to 1 part limed manure.

Overfertilizing is less a problem with soilless mixtures then with soil, because of higher concentrations of salts are tolerable in soilless mixtures and because excess salts are easily flushed out of the mixture. A good idea is to flush each pot once after two months of growth, again after four months. Any time the plants show symptoms of overfertilization, leach the pots immediately. Flood each pot with plain water so that it runs out the drainage holes. Continue flooding the pots until a couple of gallons of water have run through the pot. Don't fertilize for at least a week. Then fertilize with a more dilute solution that was used before.


Plants are considered diseased when their health or development is impaired enough that the adverse effects become visible to the eye. Disease may be caused by infectious microbes, such as bacteria or viruses, by pests such as insects, or by nutritional deficiencies or imbalances. However, for diseases that might affect your plants, there should be no need for a plant doctor. You'll be able to diagnose the symptoms after careful observation.

Leaves naturally drop from plants during the course of their lives. Not every leaf will develop perfectly or so. The small leaves that are formed during the first few weeks of growth normally die within three months. Leaves at the bottom of healthy plants often die because they are shielded by the upper instance, in a garden receiving only 80 watts of fluorescent light, the plants may stay green only up to three or four feet away from the lights. Lower leaves may turn pale and yellow and then dry to gold or rust colours.

7.2 Microbial Diseases

Because Cannabis is not native to the Americas, most of the microbial diseases that attack the plant are not found in this country. Homegrown Cannabis is remarkably free of diseases caused by microbes, and there is little chance of your plants suffering from these diseases. Fungal stem and root rots seem to be the only ones of consequence. These occur only because of improper care. Watering too often, coupled with a stagnant, humid atmosphere, encourages stem rot to develop. Stem rot appears as a brown or black discoloration at the base of the stem and is soft or mushy to the touch. Allow the soil to dry between waterings, and be sure to water around the stem, not on it. Wipe as much of the fungus and soft tissue away as possibly. If the rot doesn't disappear in a few weeks, treat it with a fungicide.

7.3 Nutrient Diseases

Diseases due to nutrient deficiencies (see section 9), are common indoors, and their symptoms usually worsen with time, affecting more and more of the plant. Whole leaves may be pale, or turn yellow or white; the condition may first afflict the bottom, or top, or the entire plant at once. Deficiency symptoms often appear as spots, splotches, or areas or chlorotic (lacking green) tissue. Sometimes necrotic (dead) tissue appears that is copper, brown, or gray. However, before you search to section 9, carefully inspect the plants for any signs of plant pests.

7.4 Plant Pests

The indoor garden is an artificial habitat where the plants live in isolation from the natural world. For this reason, few of you will have any problems with plant pests. However, indoor plants are particularly susceptible to pests once contaminated. In nature, the pest populations are kept in check by their natural enemies, as well as by wind, rain, and changing temperatures. Without these natural checks, pests can run rampant through the indoor garden.

The most common and destructive pests are spider mites and whiteflies. Spider mites are barely visible to the naked eye; they are ovoid-shaped. Juvenile mites are transparent and change to green as they suck the plant's tissue. Adults are tan, black, or semitransparent. False spider mites are bright red. Mites are usually well-established before you discover them, because they are so difficult to see.

Whiteflies are white (obviously) but look like tiny moths rather than flies. The adults are about 1/16 inch long, and you may not see one unless if flutters by the corner of your eye. Then shake the plants. If the result looks like a small snowstorm, the plants are infested with whiteflies.

The symptoms of infection by mites and whiteflies are similar. Symptoms usually appear on the lower leaves and gradually spread to the top of the plant. The first indications are that the plant loses vigor; lower leaves droop and may look pale. Look closely at the upper surfaces of the leaves for a white speckling against the green background. The speckles are due to the pests sucking the plant's chlorophyll-rich tissue. With time, the leaf loses all colour and dies.

Pests are easiest to find on the leaves that are beginning to show some damage. You can usually see mites and whitefly larvae as tiny dots looking up at the lights through the undersides of the leaves.

To find out which pest you have, remove some damaged leaves and inspect the undersides under bright daylight. With spider mites, if you discover them early, a leaf may show only one or two tiny dots (adults) and a sprinkling of white powder (eggs) along the veins. In advanced cases, the undersides look dusty with the spider mites' webbing, or there may be webbing at the leaf nodes or where the leaflets meet the petioles. With whiteflies, you usually see the adults first. On the undersides of the leaves the whitefly larvae look like mites, but there is no webbing, and there are tiny golden droplets of "honeydew" excreted by the adult whiteflies.

Take quick action once you discover plant pests. If the plants are less than a month old, you will probably be better off to clean out the garden, in order to eliminate the source of the pests, and start over. As long as the plants are healthy they can withstand most attacks. The more mature the plants are, the less they are affected by pests. Whiteflies and mites sometimes disappear from flowering plants, particularly the female flowers. Mites are difficult to eliminate completely. Often a holding action will save a good crop.

If only a few plants in your garden are infected, remove them. Or else, remove any leaves that show damage. If the plants are three or more months old, you might consider forcing them to flower while they are still healthy. Plants that are good-sized and still vigorous will usually stand up well to mites once they are flowering.

If you don't want to use insecticides, there are several alternative ways to keep the pests in check until flowering. Mix 1/8 to 1/4 pound of pure soap (such as Ivory flakes) thoroughly in one gallon of lukewarm water. Then cover each pot with foil or newspaper, invert it, and dip and swish the plant around several times in the soapy solution. Let is drip dry and rinse with clear water. Use the dunking procedure every week or two until the plants are larger. This is often enough to get the plants growing well and into flowering before the pest population can become a serious problem.

Two homemade sprays that can be effective are dormant oil sprays ((See "Insects and Pests" in the Outdoor Section.)) and hot pepper sprays.

To make hot pepper spray, mix four hot peppers with one medium onion and on clove garlic (213). Grind or chop and mash them along with some water. Cover the mash with water and allow it so stand a day or two. Add enough water to make two quarts. Strain through a coffee filter or paper towels in a funnel. Add one-half teaspoon of detergent and spray as you would an insecticide.

No one wants to use insecticides; yet they seem to be the only way to eliminate mites. There are a number of insecticides on the market that are relatively safe. Insecticides such as pyrethrum, rotenon, and malathion are relatively non-toxic to warm-blooded animals when used as directed. These are effective against many different plant pests besides mites and whiteflies. Additionally, they break down into harmless compounds such as carbon dioxide and water in a matter of days; so they do not persist in the environment.

Safe insecticides are used for vegetables. Follow all the package precautions. Do not use more, or more often, than recommended. Overuse can kill the plant. The label will list the number of days to wait before you can safely ingest the plant, usually from two to 35 days after spraying.

Both mites and whiteflies generally complete their brief life cycles in about one to two weeks. Because sprays are not effective against the eggs, repeat the spraying about once a week for three successive weeks to completely eliminate the pests. Since their generations are short-lived, some pests may become resistant to the spray. This can be a problem with whiteflies. Try a different insecticide if the first one does not seem to be working.

Add a couple of drops of liquid detergent to each quart of insecticide solution. Detergent acts as a wetting agent and helps the insecticide to contact the pests and stick to the plant. Small plants can be dunked directly in the solution, the surest way to kill pests.

To spray the plants, start at the back of the garden so that you are working away from the plants already sprayed. Spray the entire plant and soil surfaces, paying special attention to the undersides of the leaves where pests tent to congregate. Stay out of the garden and keep the room closed that day.

Sulfur dusts can also be effective against mites and many other pests, and are safe to use. The easiest way to apply them is with a plastic "squeeze" bottle which has a tapered top. Make sure you dust the underside of the leaves.

Before using any insecticide, remove all damaged leaves. Do not use any insecticide during flowering. Rinse the plant with a clear water spray about one week after applying any insecticide, and once more before you harvest. Otherwise there may be residues left which will affect the taste of the grass.

There are several other pests that can be a problem, although they rarely seriously affect marijuana. Aphids are about 1/16 inch long and are black, green, red, or pink. They have roundish bodies with long legs and antennae. Some species have wings. They congregate on the undersides of leaves which may then lose colour and become curled or distorted. Aphids excrete honey-dew droplets on the undersides of the leaves which can attract ants. If ants are also present, set out ant traps, because the ants will spread the aphids to other plants. A few successive washings in soapy water or one or two sprayings of the insecticides mentioned above should eliminate aphids.

Mealy bugs are white, about 3/16 of an inch long, and look like small, flat sowbugs. They don't seem to like marijuana and avoid it of other plants are present. Mealy bugs can be removed individually with cotton swabs and alcohol.

Gnats are attracted to moist soil that is rich in partially decayed organic matter such as manures. To discourage gnats when using manures, cover the top few inches in the pot with the soil mixture and no manure. Drench the soil with malathion solution for gnats or any other soil pest. Flypaper will also help against gnats as well as whiteflies.

Some people don't mind having a few pests on their plants. Whether you want to eliminate the pests completely or simply keep them in check may come down to whether you mind hearing the snap, crackle, and poop as their little bug bodies heat and explode when the harvest is smoked. Commercial marijuana, or any marijuana grown outdoors, will contain innumerable bugs and other small lifeforms.


Whiteflies and spider mites are extremely contagious. Mites can be carried to the plant on hands, clothing, or an animal's fur. Many houseplant pests can fly or float to the garden through open windows. Mites crawl through cracks in walls and foundations during autumn, seeking warmth.

Many houseplants are popular because they can withstand abuse and infections by common plant pests. Your houseplants may harbor mites for years without your knowledge. You can find out if your houseplants have mites by placing some marijuana seedlings among the houseplants. Mites seem to enjoy young marijuana plants so much that the plants show symptoms of mites in a matter of weeks of any are nearby.

Hopefully, you'll never have to deal with pests. Prevention is the best policy. Use soil that has been pasteurized or sterilized to avoid bringing pest eggs and larvae into the garden. Keep the garden isolated from other plants. Use separate tools for the marijuana garden and for other plants. Screen windows in the garden with wire screen or mesh fabrics such as nylon.


To start a new crop, it is best to begin with a fresh soil. This is especially true if the plants were in small pots or were root-bound.

If you have fertilized regularly, the soil may contain near-toxic amounts of salts. Most of the salts build up in the top two-inch layer of soil. To salvage large quantities of soil, discard the top three-inch layer of soil from each pot. Add fresh soil and bulk fertilizers. Thoroughly mix and repot in clean containers.

It is generally not advisable to use the same soil for more than two crops. Although the used soil may not support healthy growth for potted plants, it is an excellent addition to any garden soil. Spread the soil as you would a mulch. The salt concentration is quickly diluted and benefits, rather than harms, garden soil.

Periodically clean the tubes and reflectors to remove dust and grime. As with windows, this dirt substantially decreases the amount of light the plants receive. Fluorescents lose approximately 20 to 40 percent of their original output within a year's use. Generally the higher-wattage tubes decline more rapidly than standard-output tubes. Vita-lite tubes last the longest, followed by standard fluorescents. Gro-tubes are the shortest-lived, and most growers replace them after two crops. Older tubes can be used to start seedlings and during the first month of growth. Since the plants are small and the light system is low, the old tubes generate enough light for healthy growth. Replace incandescent bulbs after 500 light hours.

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