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

of flowering after receiving a week or more of 12/12 day/night photoperiod.

Many receptive female pistils on this ‘Hash Plant’ await pollination from male pollen. Left unfertilized, female plants continue to produce more and more cannabinoids.

‘Purple #1’
Flowering
    Cannabis flowers outdoors in the fall when days become shorter and plants are signaled that the annual life cycle is coming to an end. At flowering, plant functions change. Leafy growth slows, and flowers start to form. Flowering is triggered in most commercial varieties of cannabis by 12 hours of darkness and 12 hours of light every 24 hours. Plants that developed in tropical regions often start flowering under more light and less darkness. Flowers form during the last stage of growth. Left unpollinated, female flowers develop without seeds, “sinsemilla.” When fertilized with male pollen, female flower buds develop seeds.
    Unpollinated, female cannabis flowers continue to swell and produce more resin while waiting for male pollen to successfully complete their life cycle. After weeks of heavy flower and cannabinoid-laden resin production, THC production peaks out in the unfertilized, frustrated sinsemilla!

This pollinated female is packed with seeds. Once fertilized with male pollen, females put the bulk of their energy into producing strong, healthy seeds.
    Cannabis has both male and female plants. When both male and female flowers are in bloom, pollen from the male flower lands on the female flower, thereby fertilizing it. The male dies after producing and shedding all his pollen. Seeds form and grow within the female flowers. As the seeds are maturing, the female plant slowly dies. The mature seeds then fall to the ground and germinate naturally or are collected for planting next spring.

Chapter TWO
Seeds and Seedlings

    Grow out as many seedlings as possible to select the best mothers.

The main bud on this ‘Thai’ plant growing under the tropical sun appears to be much denser that it actually is.

Leaf from the strain ‘Thaitanic’ demonstrates the classic C. sativa characteristics-long, thin blades or fingers.

Cannabis Strains
    Technically and legally, all cannabis, whether rope or dope, is classified as Cannabis sativa. Regardless of origin, all cannabis is considered Cannabis sativa (C. sativa) under international law. However, according to Hemp Diseases and Pests, Dr. J. M. McPartland, R. C. Clarke, and D. P. Watson, CAB International, Cannabis sativa can be further classified as: Cannabis sativa (= C. sativa var. sativa), Cannabis indica (= C. sativa var. indica), Cannabis ruderalis (= C. sativa var. spondanea), Cannabis afghanica (= C. sativa var. afghanica). Each has distinct growth patterns, look, smell, taste, etc.
Cannabis Sativa
    Cannabis sativa (= C. sativa var. sativa), originated predominately in Asia, the Americas, and Africa. Each area of origin has specific characteristics, but all have the following general traits: tall, leggy stature with spacious internodal length, a large sprawling root system, large narrow-bladed leaves, and somewhat sparse flowers when grown indoors under lights. Sativas bloom several weeks to months later than indica strains. While good producers outdoors, often growing to 15 feet (4.5 m) or more, indoors pure sativa strains often grow too tall too fast—some up to ten feet in three months-to be practical for grow room cultivation. An HID bulb is unable to efficiently illuminate tall plants, and the yield-per-watt-of-light or yield-per-square-foot-of-space is very low. Mexican, Columbian, Thai, and Jamaican strains can be very potent, with a high THC to CBD ratio that produces a soaring, energetic, “speedy” high. But potency can also be minimal, with low levels of THC. Most exported Columbian, Mexican, Thai, and Jamaican marijuana is poorly treated throughout life and abused when dried and packed. This abuse causes more rapiddegradation of THC. Consequently, seeds from fair smoke are often more potent than the parent.
    Central African sativas, including the THC-potent ‘Congolese’, grow similarly to Columbian strains, with a tall leggy stature, often growing more than 15 feet (4.5 meters) tall with loosely packed buds.
    South Africa has major seaports. Sailors brought Cannabis sativa from many different places and planted it in South Africa. Consequently, potency of South African weed can be very high or very low, and can grow short, tall, leggy, bushy, etc. The famous ‘Durban