Marijuana Grower's Handbook

by Ed Rosenthal

  Pollen remains useable for years when packed with a desiccant and stored in a sealed container in a freezer.

  Once the cuttings have indicated remove the corresponding male plants from the garden and destroy them. They have no use except in breeding programs. Sentimentality should play no part your decision. The indicator cuttings are not worth saving, either.

  (For more on Sinsemilla and Sexing see Flowering.)

  EARLY PLANT GROWTH

  In a few weeks, the plants grow a foot (30 cm) or more in height and develop branches typical of their variety. By now, plants from standard seeds should be sexed, leaving only females in the garden. If the plants have been transplanted to a small container from their seedling or clone container, the plant should be transplanted to their final container or the ground.

  Seedlings and clones that are transplanted into hydroponic units or an un-enriched planting mix need fertilizers to supply them with nutrients. Start both clones and young plants on fertilizer with a nitrogen-phosphorous-potassium (N-P-K) ratio of 1-1-1, 3-5-5, or 3-4-2 with micronutrients on the mild rather than strong side. Limiting the amount of N in relation to P and K increases stem diameter and discourages elongation.

  After transplanting, keep the temperature in the low 70’s F (low 20’s C), if possible. Photosynthesis is limited when the air is kept cool. Since less water and nutrients are required with slower photosynthesis, the roots don’t get stressed and there is less chance of wilting. Keep the CO2 at 500-600 ppm, giving the plants easy access to the gas.

  After three days or so, the plants are entering vegetative growth. Increase the CO2 to 1,200 ppm, raise the strength of the water-nutrient solution to mid-range, and bring the temperature to 80° F (26-27° C). Keep the lights on 24 hours a day if the plants are to be grown indoors. However, if the young plants are destined to be grown outdoors, cut the light regimen to 18 hours of light, 6 hours of darkness. Some varieties, especially indicas, are less likely to be shocked into flowering when moved outdoors if they spend the indoor segment of their lives under a regimen of 16 hours of light, 8 hours of darkness.

  PLANT AND CONTAINER SIZE

  Indoors and out, the size of the container helps to determine the size of the plant and its yield. As mentioned earlier, if two identical plants are given the same conditions except for container size, the plant in the larger container will produce more. For this reason it’s wise to give roots as much room as possible to spread out. Indoors, the container size should be limited only by the space each plant has in the canopy.

  Both planting mix and hydroponically grown plants produce more when they are grown in the largest containers possible. Containers should taper slightly so that plants and medium can slide out easily. Plastic containers are usually the most convenient to use because they are lightweight, do not break, and are inert. Plastic grow bags are convenient containers, especially for outdoor gardeners. They take up little room in a backpack and are easy to set up. They have a square bottom so they balance easily and remain upright. Special woven plastic containers have handles that make moving plants around an easy task.

  Fiber containers are also popular. They are inexpensive, last several growing seasons and are biodegradable. Metal containers are not recommended because they react with the nutrients in the solution.

  CONTAINER SIZES

  These recommended container configurations all assume a garden space 12 to 16 sq ft (1-1.5 sq m) powered by a 600w or 1000w HPS.

  •A single plant can be grown in a container as large as 50 gallons (190 liters or 6.7 cubic feet).

  •Two plants can be grown in two containers as large as 30 gallons each (113 liters or 4 cubic feet).

  •Four plants can be grown in four containers as large as 20 gallons each (75 liters or 22⁄3 cubic feet).

  •Eight plants can be grown in eight containers as large as 10 gallons each (38 liters or 11⁄3 cubic feet).

  •Sixteen plants can be grown in 16 containers as large as 5 gallons each (19 liters or 2⁄3 cubic feet).

  VEGETATIVE GROWTH

  As soon as the roots have adjusted to the new environment, it is time to increase the light and nutrients. Firm, turgid leaves and new growth are indications that the plant is ready for rapid growth.

  Turn the lights to their maximum level for vegetative growth, and change the fertilizer solution to one with nitrogen-phosphorus-potassium (N-P-K) ratio close to 3-1-2, 4-2-3, or 5-3-3. The plants should be kept on a high N fertilizer regimen until they are put into the flowering regimen. “Grow” formulas that include micronutrients support rapid vegetative growth.

  INDOORS

  You can start vegetative growth indoors any time it’s convenient, since you determine the plant’s environment and simulate seasonal variations by adjusting the periods of light and darkness.

  Nonetheless, seasonal conditions can affect your decision about when to plant. In some areas, summer heat or bug infestations make it inconvenient or impractical to grow during the summer. In such areas, indoor gardens may be shut down or downsized to just mothers or clones before being restarted in the fall.

  OUTDOORS

  Gardeners using natural light either as a primary or secondary source must take the seasons into account. Planting time and strategies vary depending on the environment.

  The earliest that seedlings or clones should be planted outdoors is when the soil temperature three inches (7.5 cm) below the surface reaches 65˚ F (18˚ C) in the afternoon and slips no lower than 50˚ F (10˚ C) at night. They can be planted when ground temperatures are lower, but growth will be slow until the ground heats up.

  Marijuana seed is best planted when the minimum soil temperature doesn’t slip below 60˚ F (15˚ C). At lower temperatures the seeds absorb moisture but root and sprout initiation are delayed. This leaves the seed vulnerable to attack by fungi and yeasts. In areas where there are four distinct seasons, clones or starts should be planted outdoors at the same time as tomatoes.

  Plants started or transplanted outdoors from late April through July will ripen between September and November, depending on the variety. No artificial light is needed as long as there is plenty of sunshine.

  As discussed in more detail in the lighting section, supplemental artificial light can be used to help the plants to maturity in the fall. At higher latitudes, the intensity of light plants receive from the sun in September or October is a fraction of the light in June. The amount of UV light also diminishes.

  Plants use light for growth. When they are shaded they don’t get very much light and growth is slowed.

  The sun’s angle changes over the season, too, so plants that were in direct light in spring and summer may be in shadow by autumn.

  If your plants are in containers, you may be able to move them to get more direct sunlight. Plants in the ground that are in shadow require supplemental light to grow and ripen properly.

  On overcast days, clouds absorb most of the light, so overcast periods also delay ripening. Even sunny gardens receiving direct but weak sunlight may require more light for the buds to develop well.

  Supplying the plants with 10-30 watts per square foot (110-330 watts per sq m) of supplemental light, depending on the type of lamp, from HID lights, CFLs, or HO T-5 fluorescents during the brightest part of the day is all that is needed to help the buds mature in September or October. See the lighting section for how to select the appropriate type and wattage of lamp for your needs.

  Gardeners in lower latitudes, such as Mediterranean and sub-tropical regions, can grow outdoors virtually the entire year. These areas include the southern tier of Europe, the southern tier of the United States, and all of Mexico and Central America. In these lower equatorial latitudes, day length and light intensity does not vary as much between summer and winter as in higher latitudes.

  Most indica and indica/sativa hybrids are early ripening, meaning they require the least amount of darkness to flower. Some varieties trigger immediately when placed outdoors; for them, the night length
is long enough in both summer and winter to promote flowering.

  One strategy for taking advantage of this is to grow plants indoors until they reach the desired size, then set them outside to flower. They will grow another 25-50% larger during their flowering period.

  Sativas and sativa/indica hybrids are usually late-season varieties that require a longer dark period to flower. Some equatorial sativa varieties do not start to flower until late September and don’t ripen until December or January. In winter, flowering is induced quickly, but the plants may continue to grow vegetatively for a month or more before they concentrate their energy on flowering. The result is that they can be planted any time of the year. Plants transplanted outdoors in the spring and summer flower in late fall. Sativas set out between August and December ripen within 120 days; indicas ripen in 60 days or less.

  Greenhouses and natural light gardens in temperate areas can be used to grow up to three crops a year using supplemental light. The determining factor is root and air temperature. Plant growth is slow when air temperature is below 60˚ F (15˚ C). It quadruples with adequate light as the temperature increases from 60 to 80˚ F (15˚-26˚ C). At the same time, ground temperature below 65˚ F (18˚ C) hinders root function, which affects the supply of water and nutrients to the canopy. With this in mind, you can plan your garden based on average temperature for your area, which can be found in almanacs or on the Internet.

  In subtropical areas gardens can be planted all year. In some warm areas, where spring comes early, gardens can be planted in early February, as the sun’s intensity starts to increase. Young plants placed outdoors immediately start to flower, because the night period is still longer than 12 hours.

  Indicas and indica-sativas continue to flower as the days get longer. However sativas and sativa-indicas revert to vegetative growth unless flower forcing continues using light deprivation techniques such as blackout covers.

  The size or age of the plant has no effect on the quality of the bud. Small plants are often more convenient because they can be moved around with the sun.

  In some areas, it’s just too cold to plant in February or even in April, but greenhouses move the planting period forward by about three weeks. A heated greenhouse can overcome inclement and cold conditions, but cloudy spring skies may not provide quite enough light to the plants. HID lamps or CFLs can provide supplemental light for 5 or 6 hours during the brightest part of the day.

  Removable tunnels are another way to get a jump on the season. They keep the outdoor garden warm and sheltered from the cold, wind, and rain. They are easily constructed using rebar or metal pipe covered with (6 or 8 ml) clear polyethylene. The plastic is removable, so it is placed over the plants only when there is cold or inclement weather. In early spring, it might be used nightly. The tunnels should be constructed about 6' (1.75 m) high so they can be used for forcing flowering with blackout covers later in the season. They are often 10' (3 m) wide, but can be designed for any width.

  Using a tunnel or a greenhouse, it’s possible to manipulate the light cycle to either prolong vegetative growth or to force the plants to flower. Using these techniques, it takes 90 days or less to produce a crop, depending on the variety.

  One example of greenhouse strategy is to plant April 1st. The plants will ripen June 15th or earlier. Immediately after harvesting the June crop, the next crop is planted and will ripen by August 30th. A third crop is then started. It will flower immediately and is ready by November 15th.

  Even if you’re not trying to squeeze in multiple crops, there are several advantages to forcing an early harvest.

  •The crop is less vulnerable to thieves or law enforcement, who look for gardens primarily during the fall harvest season.

  In tropical and sub-tropical areas where plants can be grown outdoors in winter such as parts of the Southern United States, Hawaii, and portions of the Mediterranean, pure sativas have the time to flower under short days. In more northerly areas plants in greenhouses have the same opportunity; however, the plants may need supplemental lighting to produce grade A buds.

  •Second, plants harvested in summer are not vulnerable to mold or the vagaries of weather that plague farmers in the fall.

  •Third, the bud quality is higher when plants flower and are harvested under the strong UV rays of summer.

  During early spring, plants usually require an interruption of the night cycle so they do not go into the flowering stage prematurely. Lights on a timer can be used to interrupt the dark period briefly during the night. For instance, a 400w HPS covers an area of about 600 sq ft (55 sq m) with enough light to stop flowering. Or you can use CFLs at a ratio of one 24w bulb per square yard or square meter. Flash the lights on for 10 minutes using a multi-cycle timer at least once during the middle of the dark period. Gardeners with large spaces sometimes stagger the timing of the night lights.

  Night and day are each 12 hours long two days a year: the spring and fall equinoxes. After March 22, the Northern hemisphere spring equinox, nights continue to grow shorter until June 22, the first day of summer. The summer solstice has the longest day and shortest night, though the number of hours varies depending on latitude. After that, the night starts to lengthen again until it reaches 12 hours of sunlight and 12 hours of night on the fall Equinox, September 22. The longest night is December 22, the winter solstice.

  HPS reflectors are available that oscillate a 1000 watt lamp, which covers 1,500 sq ft (130 sq m).

  Incandescent bulbs are not very efficient or as effective as fluorescents because they emit far-red light, which counters red light’s inhibitory effect. HPS lamps and warm white fluorescents emit a high percentage of red light, the spectrum used by plants to prevent flowering.

  REGENERATION

  Regeneration is the technique of using mature plants, whose ripened buds have been harvested, to produce a second harvest. It can be used indoors or out, but is most frequently used outdoors.

  Since marijuana grows and flowers based on the number of hours of light and darkness, manipulating its light cycle can convince a flowering plant to return to vegetative growth.

  When the buds are harvested, leave undeveloped flowers and many of the leaves on the plant. Increase the light regimen to support vegetative growth; indoors leave the light on continuously; outdoors use night cycle interruption. The plant may start re-growing vegetatively, a process known as regeneration. Leaves start to grow and the plant exhibits renewed vigor.

  This can also happen under natural light conditions when flowering was induced early in tunnels or a greenhouse. Spring crop plants often revert back to vegetative growth under the long days of June and early July. Some varieties require an interruption of the dark period using artificial light. As the nights get longer, the plants revert back to flowering, producing buds that will be ready for harvest in the fall.

  Gardeners can use this to their advantage in several ways. Plants that were grown indoors under lights and harvested can be placed outdoors to generate a second harvest. Indoor plants that were grown to a large size to satisfy legal restrictions on plant numbers can be harvested, regenerated, and then induced to flower again. Because they already have an infrastructure of roots and stem, they can be forced to flower faster, shortening the time between harvests. Outdoor plants that were forced to flower early for harvest in July or early August can be regenerated and re-flowered to produce a second harvest. In warm areas, plantings can be timed for three harvests, at least two of which are from the same plant. Spring plants that were flowered and harvested indoors can be placed outdoors without treating them to continuous light. The long days of early summer combined with the increased intensity of the sun’s light push them back into vegetative growth.

  When most varieties receive light for long periods they revert back to vegetative growth. Harvested plants can be placed outdoors to regenerate and produce a fall harvest.

  This plant signals its crossover back to vegetative by growing a swirled leaf. This trait was first not
iced by the famous breeder Soma.

  The regeneration process starts with harvest. Instead of harvesting the whole plant by cutting the stem off, or cutting off all the branches, leave parts of some branches intact, including green leaves and small parts of buds. Then place the plant under continuous light. In 7-10 days the plant will start to grow vegetatively again. At this point, the light can be cut to 18 hours. When the plants have grown enough new vegetation to support heavy flowering on colas, change the light cycle back to flowering: 12 on, 12 off. The plants will start to flower as usual.

  Use HPS lamps to supplement natural light when it has a low intensity and to increase the length of the lighted period.

  Shading was used to induce these plants to flower during the summer.

  This greenhouse is heated passively using dark, water-filled wine bottles placed along the north wall. The bottles absorb and store heat from sunlight and the warm air during the day and release it at night.