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

temperatures make more male plants.
    High humidity increases the number of female plants. Low humidity increases male plants.
    Low growing-medium moisture increases males.
    More blue light increases the number of female plants. More red light increases male tendencies.
    Fewer hours of daylight (e.g. 14 hours) increases the number of females. Longer days (e.g. 18 hours) make more male plants.
    Stress: any environmental stress tends to yield more male plants when growing from seed.
    Henk, owner of Dutch Passion Seeds, http://www.dutch-passion.nl , was kind enough to allow us to adapt this information from his archives.
    See Chapter Sixteen, “Breeding,” for information on producing feminized seeds.

Seedlings
    When a seed sprouts, the white taproot emerges. Soon afterward, the cotyledon, also known as seed or seedling leaf, appears. The seed leaves spread out as the stem elongates. Within a few days, the first true leaves appear, and the little plant is now officially a seedling. This growth stage lasts for three to six weeks. During seedling growth, a root system grows rapidly while green aboveground growth is slow. Water and heat are critical at this point of development. The new, fragile root system is very small and requires a small but constant supply of water and warmth. Too much water will drown roots, often leading to root rot and damping-off. Lack of water will cause the infant root system to dry up. As the seedlings mature, some will grow faster, stronger, and appear healthy in general. A little heat now will help nurture small seedlings to a strong start. Other seeds will sprout slowly and be weak and leggy. Cull sickly, weak plants, and focus attention on the remaining strong survivors. Seedlings should be big enough to thin out by the third to fifth week of growth. Thinning out seedlings is very difficult for growers who pay $300 dollars for a few seeds!
    Seedlings need at least 16 hours of light daily. They require less intense light now and grow well under fluorescent tubes for the first two to three weeks. Compact fluorescent and HID light can also be used. The compact fluorescent should be 12-18 inches (30-45 cm) and the HID 3-4 feet (90-120 cm) above seedlings for best growth.
    The seedling stage is over when rapid foliage growth starts. Rapid growth above ground is the beginning of the vegetative growth stage. Plants need more room to grow; transplanting into a larger container hastens development.

Seedlings emerging from peat pots develop seed (cotyledon) leaves before growing their first set of “true leaves.”

‘Blue Satellite’ seedlings are flourishing in this Styrofoam cup. They were transplanted the day the photo was taken.

Strong, healthy seedlings like this ‘White Widow’ are the key to a heavy harvest.

Small ‘Thaitanic’ is at the end of the seedling stage of growth.

Deep plugs grow a deeper root system. This seedling was transplanted outdoors and grew very well.

Storing Seeds
    Store seeds in a cool, dark, dry place. Make sure to label containers! Some seeds will remain viable for five years or longer when stored properly. When 50 percent of the stored seeds do not germinate, the average storage life is over. But seeds a year old or older often take longer to sprout and have a lower rate of germination.
    Seed hormones–ABA, cytokinins, and gib-berellins–are primed to respond to moisture, which is the first signal to germinate. Prevent moisture from signaling seeds to germinate by keeping them dry. Small amounts of moisture in the form of condensation can give seeds a false start on germination and cause them to expend all their stored energy. Avoid moisture levels above five percent to ensure viable seed. Moisture levels above five percent will cause germination levels to decrease rapidly. Seal seed in an airtight container, and place silicon crystal packages in the container to absorb excess moisture.

Seeds store for a long time when humidity is less than 5 percent and temperature is 35-40° F (2-5° C).
    Cannabis seeds need enough moisture to initiate this process within 48 hours.
    Hit our site, www.marijuanagrowing.com for updated information about seeds.
    Dry seeds are temperature-sensitive; they can be disinfected with a short application of heat. Low temperatures slow internal seed activity so are best for preserving seeds. You can use super-cold liquid nitrogen and cryogenics to store seeds for a long time.
    Air, once it enters the outer seed shell, signals