Marijuana Grower's Handbook

by Ed Rosenthal

  PLANT TISSUE CULTURE CLONING

  Tissue culture cloning, or micropropagation, is an alternative to traditional cloning techniques. It eliminates mother plants and the resources they require. Instead, new plants are grown and rooted in small jars on a nutrient gel made of sugar, agar and plant hormones. Tissue culture clones can be prepared at home without a formal laboratory.

  Tissue culture is being used by the agriculture, floriculture and horticultural industries. Rather than breeding to create a variety, generations of new plants are based on a “best plant” model. Once a particular specimen with superior characteristics is developed, it is regenerated asexually. Tissue culture is used to create millions of copies in a short time, very inexpensively.

  Plant tissue culture is gaining popularity as a way to make rooted clones because of the availability of prepared kits and lab-quality supplies. Commercial greenhouses use this technique to clone their plants by the hundreds of millions. Most crops including houseplants, pineapples, fruit trees and agave plants begin life in these small jars and grow into full-size plants.

  The plants start from small node cuttings put into a culture. Typical tissue culture cloning jars produce five to eight new plants every four to six weeks. When plants reach 0.75” (2 cm) or larger they are removed for rooting.

  Smaller immature plants are put into fresh multiplication jars to grow all over again. These are called mother jars because they are like mother plants that don’t wear out. The clones are rooted in tissue culture using the same hormones growers use to take cuttings. The difference is that the clones are smaller and many more are produced in a small area. Once in the jars the plants have all of the resources they need to grow by themselves.

  Tissue culture clones grow in sterile culture so they are pest-and disease-free. Only a small part of the mature clump of shoots is needed to grow a brand new jar full. When new plants fill the jar the contents are moved to a sterile plate where the largest plant pieces, the microclones, are cut from and planted in a larger rooting tub to give the plants room to spread out and grow.

  The remaining base of undeveloped plants is planted in a new multiplying jar, where it continues to grow. The “deflasked” clones are treated like regular clones; they are kept under a humidity dome for a few days until they develop a protective waxy coating, or cuticle. The plants root over a few weeks until they are ready to transplant.

  There are only two steps in the process to create tissue culture clones. First, the media is prepared in a process similar to making Jell-O® and then sterilized in a pressure cooker. The important second step is to ensure 100% sterile conditions. Handling is done with a scalpel and forceps in a protective plastic storage tote. All tools and surfaces are cleaned with alcohol.

  The containers keep the plants small because they grow only to the size of their container. Sugar provides energy directly to the plant and supports growth; the hormones steer the growth towards branching or rooting; and the preservatives keep it all clean. It is an ideal automatic growing system not only for cloning and storing plants, but also for sharing and transporting crops. Tissue culture clones are shipped around the world every day by the thousands; tissue culture creates opportunities to improve cannabis crops genetically. For instance, tissue culture has the potential to induce polyploidy, a naturally occurring mutation that increases the number of chromosomes in a plant or animal. Polyploid plants tend to be larger and more vigorous; they may also reveal hidden genetics, create seed-like embryos without pollination, and even generate “synthetic” seeds.

  The scale of tissue culture can be increased to create a tissue culture bioreactor, a vat of plants that multiplies like yeast in beer.

  Chromosome doubling can be induced in tissue culture by adding chemicals such as colchicine or sulfluran. Although colchicine is the most commonly used, the chemical sulfluran is less toxic and can be purchased in farm supply and some hardware stores. The chemicals disrupt the cell division process. Instead of dividing as normal into two new cells after the chromosomes duplicate, the division pauses and the cell begins growing again but with twice as much DNA as it should have.

  Plants that grow from polyploid cells have the potential to be bigger and stronger than their parents. Many cannabis plants have hidden genetics in them that may be revealed by polyploid tissue culture.

  FEMINIZING SEED

  Feminized seeds produce only female plants, and when they germinate there will be few males among them if they are produced correctly. The threat of accidentally pollinating crops by misidentifying a male is minimized. A male-free crop is only one reason to use all-female seeds: another might be the preservation of a particular characteristic or plant type.

  The predominant way to preserve the exact genetics of a plant is by cloning. However, a plant crossed with itself produces seeds that retain its parent’s favorable characteristics. Another reason to use this technique is to create a hybrid of two female plants. If a branch of one female is turned “male,” there will be pollen to fertilize the other plant, and to create seed when no male is around. Feminized seeds are produced by inducing a normal female, not a hermaphrodite, to grow male flowers with viable pollen. The pollen contains only female, or X, chromosomes because the plant has no Y, or male, chromosomes. The progeny will inherit an X from the male flower’s pollen and an X from the egg donor female flower. The resulting seeds can only inherit two X chromosomes, which means that almost all the resulting seeds will be girls! Congratulations!

  With the help of gibberellic acid 3 this female plant is expressing male flowers.

  Male and female flowers on a treated plant.

  FEMINIZED SEEDS | BY HENK VAN DALEN*

  I started growing cannabis for myself outdoors in the Netherlands in 1972, and in 1987 I founded Dutch Passion Seed Company. Inspired by Ed Rosenthal and Mel Frank’s Marijuana Grower’s Guide, I dreamed of creating seeds that would produce only female plants. It wasn’t until 1995 that I began developing a technique to produce feminized seed strains.

  It became evident that almost all unpollinated female plants would inevitably produce some male pollen. This is a survival mechanism: when a female plant is not pollinated by a male plant, it generates male pollen to fertilize itself. After self pollination, the female plant bears seeds.

  By systematically collecting pollen produced by these hermaphroditic female plants and fertilizing flowers on other females, I was able to produce feminized seeds. Seeing them all grow into female plants was a rewarding experience. I soon started selling feminized seeds on the German market, which was legal in the mid-90’s. Customers were pleased with the results, and we sold out. But we couldn’t produce more.

  The process we were using meant that we were only able to produce and harvest a small amount of female pollen, which seriously limited production. It took a lot of effort to produce a few thousand seeds. The question then was, how do we get abundant “female” pollen to produce as many feminized seeds as the market demands?

  I found the answer at the Agricultural University at Wageningen. Researchers there had done similar work with other plant species, such as cucumbers. They had discovered that plant hormones and less complex agents can drastically change the physiology and morphology of the cucumber. It then took us about two years to check which hormones and other agents could enhance pollen production in female cannabis plants without disrupting their normal growth pattern.

  Feminized seeds are now the standard for all seed companies, which shows that feminized seeds work—which was widely doubted at first. Feminized seeds are an excellent choice for marijuana cultivation.

  Close-up of plant treated with silver thiosulfate.

  Getting only female plants was the motivation for creating feminized seeds, but they offer other advantages. Feminized varieties are more uniform (homogenous) than “regular” seeds. Plants from feminized seeds tend to look more like each other and produce a more uniform harvest.

  Even when using feminized seeds, there is
still a small chance that you will have a few plants that are hermaphrodites (truly both male and female) or males. You should monitor all your plants through the entire growth stage to check for these oddities. Maintaining stable growing conditions is the best way to prevent male or hermaphroditic plants. Environmental stresses such as light, disruption, or overpruning will encourage female plants to produce pollen. If you do find a male or a hermaphrodite, remove it.

  Feminized seeds are not as mysterious or weird as they might seem. In mature human females, taking male hormones causes masculinizing changes such as breast shrinkage, muscle bulking, and a lowering in voice pitch. The primary sex organs have already been formed, but they shrink.

  A similar thing happens when female plants are treated with masculinizing chemicals. The difference is that while a mature human has already formed her sex organs, every time a plant produces a new flower, it is growing a new sex organ. Plants under chemical influence grow viable male flowers, even though the plant is still a female with two X chromosomes, the pollen has only female chromosomes.

  There are several methods used to produce feminized seed. By far, the noted breeder Soma developed the easiest method. He noticed that when colas of many varieties reached late ripeness (which, by the way, I prefer as the harvest-time) a few viable male flowers appear. This is also a sign that the buds are ripe. Harvest the pollen using a fresh watercolor brush and brush it directly on the flowers or store it in a small glass or metal container. Not all varieties produce male flowers at the end of ripeness, but many do, and they do it reliably. Very small amounts of pollen are produced using this method, but a little pollen applied properly goes a long way.

  Some varieties flower normally outdoors but experience indoor growing conditions as stressful and produce hermaphrodite flowers. The pollen from these male flowers can be used for breeding, provided that the resulting plants are going to be grown outdoors, where they won’t exhibit the unwanted hermaphroditism. Plant stresses such as irregular light cycles and heat sometimes induce hermaphroditism. However, stress techniques are not reliable. They only seem to work when you don’t want them to, and I haven’t found a stress regimen that ensures masculinization. Should this happen accidentally in a garden with a valuable variety, be opportunistic and collect the pollen, even if you have no plans to use it.

  Several light sprays of gibberellic acid (GA 3) induce hermaphroditism and stretch the plant.

  Laboratories and commercial seed producers use three chemicals to induce male flowers in female plants: gibberellic acid, silver nitrate, and silver thiosulfate. They each inhibit the plant’s production of ethylene, a hormone that promotes female flowering. Without ethylene, female flower production is reduced or stopped. The actions of these chemicals are localized. If only one branch of a plant is sprayed, that branch will be the only one affected. The rest of the plant will continue growing female flowers, not males.

  Gibberellins are hormones that plants produce to regulate many phases of their growth. Several of the gibberellins, such as GA3, 4, 5 and 7, induce male flowers when they are sprayed on female plants before they begin flowering. GA3, which is the gibberellin most commonly available commercially, is the most effective. For best results, use a solution of 0.01% (0.1 gram GA3 in a liter of distilled water). Gibberellin must be used carefully. Lower doses result in fewer male flowers. Higher amounts have an inhibitory effect. Lightly spray the tops of the plant for five consecutive days and then force the plants to flower by increasing the uninterrupted dark period to 12 hours a day. The sprayed area will stretch a bit, but within two weeks, the first signs of male flowers will appear. They will be ripe and ready to release pollen in another two weeks.

  Silver thiosulfate is more effective than silver nitrate; that is, it induces more male flowers. Sometimes the two chemicals are used together. Spray the plant until the liquid drips off the leaves. Then immediately change the light regimen from vegetative to flowering. The leaves will droop and stop growing for a few days, yellow a bit and then regain turgidity. Male flower growth will become apparent in a couple of weeks. The flowers will ripen a few weeks later.

  Silver thiosulfate is made by combining two water solutions, one containing silver nitrate and the other, sodium thiosulfate. Silver nitrate alone can also be used to induce male flowers. Spray a solution of 0.02-0.03% on the plant, and then turn the lights to a 12-hour flowering cycle. The leaves will droop for a day or so and then resume turgidity. Male flower growth will become apparent in a couple of weeks and ripen a few weeks later. To make a 0.02% solution, add 0.1 gram of silver nitrate in 0.5 liters of distilled water.

  Because of market demand, almost all the seed companies offer most of their popular varieties as feminized seed. They are the best choice for most gardeners. The exception is gardeners interested in breeding.

  POST HARVEST

  TRASH BASICS

  Leaves and trim, the natural byproduct of growing buds present an interesting paradox. The bud is the plant’s crown jewel with 5-20% THC. However, cannabis produces THC throughout the plant. Sticky resin glands coat the leaves and bracts, creating a natural protective barrier against insects, disease, herbivores and the sun’s UV rays.

  Glands on the leaf and trim contain one-fifth to one-half the THC found in the buds. The fan leaves have a THC content of only 1-3%, and they are a harsh smoke. Trim, with 2-6% THC content, commands only a little more respect than the leaves.

  Buds typically weigh four times as much as the leaf on a mature female marijuana plant, although this varies tremendously by variety and gardening technique. Still, when trim and leaves are tossed, 10-20% of the plant’s total THC production may be thrown away.

  Collecting and using the trash does not add greatly to the complexity of harvest. Leaves and trim are already being trimmed and bagged. Preparing to dry and store this material in advance makes the collection almost as simple as bagging it for the trash can. Once the trash is saved and stored properly, transforming the leaves and trim into stash can wait until the rush of the harvest is complete.

  KNOW YOUR TRASH/COLLECT FOR STASH

  When tossing it out, trash is everything that isn’t bud. If you are going to use it, it should be sorted. Stems and woody parts of the plant are not salvageable. The sticks and stems have little THC, so they really are trash.

  GRADES OF TRASH

  All leaves from mature female plants contain retrievable THC. Male plants contain THC as well, and are most potent at the budding, pre-flowering stage. In both cases, the small leaves near the flowers are the most potent, followed by the younger and then older fan leaves.

  It may be useful to get a magnifying glass or photographer’s loupe and take a close-up look at the plant material. The glands on the fan leaves are often small and hug the surface of the leaf, while the glands on the flowers are stalked and look like mushrooms with bulbous caps. Material with visible glands is worth keeping. While immature material can also be collected, it is best to use leaf that has been collected from mature plants to get the intended results. In a recycling effort, a gardener may opt to trash material with the sparsest glands, such as the large fan leaves, while saving the smaller leaves, trim and buds for use.

  Processing the leaf and trim for use as kief, hash, tincture, butter or food requires additional effort that may not seem worth it to a person floating on good weed. It creates another task at harvest time, when there is already a lot of work to be done. Danger of rip-offs or busts may limit the marijuana gardener from adding another step to the harvesting process. Perhaps it's best to transfer the job to a professional processor.

  KIEF

  Kief is an easy process, but a controversial word. Alternatively spelled as kif, kief, kef, and kiff, it appears in many languages around the world. Kief is a powder that consists of the loose glands removed from marijuana buds and plant material. It looks like minute grains of sand.

  Some marijuana enthusiasts debate the use of the word kief, because this term was originally used i
n cultures such as Moroccan to mean a mixture of grass and tobacco. In Amsterdam and other parts of Europe, kief is sometimes called pollen or polm. In French and Afrikaans, the word kief is also a slang term that means cool or great.

  Countries close to the 30th parallel, including Afghanistan, Lebanon, Morocco and Nepal have traditionally made kief as the first step to making hashish.

  There are many techniques for removing the THC holding trichomes from the vegetative material to which they are attached.

  The simplest way to make it is to use a silk scarf stretched tightly over a bowl. The fine weave of the cloth allows the THC glands to pass through, separating them from the vegetative material.

  Screening works because glands are consistently within a certain size range and pass through the pliable holes in the silkscreen weave.

  The gland heads are measured in microns, which is a metric measurement equal to one millionth of a meter. Glands range between 75-125 microns in size. Maturity, variety and environmental conditions determine gland size. Moroccan varieties’ glands are usually under 80 microns. Sativa glands are also small. “Hash plant” varieties’ glands are often 120 microns or larger. Most sinsemilla have glands in the mid-range, between 80-110 microns.

  " Talk about your plenty Talk about your ills One man gathers what another man spills"

  Lyrics: Robert Hunter The Grateful Dead, "St. Stephen"

  THE LEAF HIERARCHY

  This list prioritizes salvageable material according to its THC content.