Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

Netherlands, the United Kingdom, Canada, France, Switzerland, Spain, etc., has given way to more strains of cannabis than ever before. Most popular strains of cannabis are a combination of two or more of the following: C. sativa, C. indica, C. ruderalis, and C. afghanica. But there are also many seeds with the genes from just one of the above. These strains of cannabis are bred to grow best indoors. Others grow best in greenhouses, and still others outdoors in specific climates. See Chapter Sixteen, “Breeding,” for information about hybrid seeds including F1, F2, F3, etc., hybrids.
    A seed contains all the genetic characteristics of a plant. Seeds are the result of sexual propagation and contain genes from each parent, male and female. Some plants, known as hermaphrodites, bear both male and female flowers on the same plant. The genes within a seed dictate a plant’s size; disease and pest resistance; root, stem, leaf, and flower production; cannabinoid levels; and many other traits. The genetic makeup of a seed is the single most important factor dictating how well a plant will grow under artificial light or natural sunlight and the levels of cannabinoids it will produce.
    Strong, healthy parents and proper care yield strong seeds that germinate well. Strong seeds produce healthy plants and heavy harvests. Seeds stored too long will germinate slowly and have a high rate of failure. Vigorous seeds initiate growth within seven days or sooner. Seeds that take longer than a month to germinate could always be slow and produce less. However, some seeds take longer to germinate even under the best conditions.
    The cask, or outer protective shell, on some seeds never properly seals, which allows moisture and air to penetrate. It alsocauses hormone concentrations to dissipate and make seeds less viable. Permeable seeds signal diseases and pests to move in. Such seeds are immature, white, fragile, and crush easily with slight pressure between finger and thumb. These are weak seeds and do not have enough strength to grow well.

The cutaway drawing in the center shows how the seed will develop into different plant parts.
    Typically, a grower who acquires a bag of ten quality seeds from a reputable seed company germinates them all at once. Once germinated, the seeds are carefully planted and grown to adulthood. By and large, of the ten seeds, some will be male, some will be weak and grow poorly, and two or three seeds will grow into strong, super females. Of these “super” females, one will be more robust and potent than her siblings. This super female is selected to be the mother of countless super clones.
    A simple picture of a seed reveals an embryo containing the genes and a supply of food wrapped in a protective outer coating. Mature seeds that are hard, beige to dark brown, and spotted or mottled have the highest germination rate. Soft, pale, or green seeds are usually immature and should be avoided. Immature seeds germinate poorly and often produce sickly plants. Fresh, dry, mature seeds less than a year old sprout quickly and grow robust plants.

Germination

Seeds in this seeded female swell and break open the seed bract
    Cannabis seeds need only water, heat, and air to germinate. They do not need extra hormones to germinate. Seeds sprout without light in a wide range of temperatures. Properly nurtured seeds germinate in two to seven days, in temperatures from 70-90°F (21-32°C). Temperatures above 90°F (32°C)impair germination. At germination, the outside protective shell of the seed splits, and a tiny, white sprout (radicle) pops out. This sprout is the root or taproot. Cotyledon, or seed leaves, emerge from within the shell as they push upward in search of light.
     
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Timeline for germinating seeds
    At 55-72 hours
    Water is absorbed
    Root tip (radicle) is visible
    At 10-14 days
    First roots become visible
    At 21-30 days
    At least half of seeds are rooted by day 21. Seeds not rooted by day 30 will probably grow slowly.
    Once seeds are rooted, cell growth accelerates; stem, foliage, and roots develop quickly. Seedlings develop into full vegetative growth within four to six weeks of germination.
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    Seeds are prompted to germinate by:
    Water
    Temperature
    Air (oxygen)
Water
    Soaking seeds in water allows moisture to penetrate the protective seed shell within minutes. Once inside, moisture continues to wick in to activate the dormant hormones. In a few days, hormones activate and send enough hormone