Cannabis Sativa

Marijuana Horticulture

by Jorge Cervantes

Cannabis sativa (= C. sativa var. sativa), originated predominately in Asia, the Americas, and Africa. Each area of rigin 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 or more, indoor 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 rapid degradation 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 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 Poison yields potent, pale green, early buds and is the best-known South African strain.

Asian sativas, including Thai, Vietnamese, Laotian, Cambodian, and Nepalese, have diverse growth characteristics and vary significantly in potency. While Thai and other sativas from the area are often super THC-potent, they are some of the most difficult to grow indoors and the slowest to mature. Thai strains produce very light, wispy buds after flowering for about four months on plants with large, sprawling branches. Thai, Vietnamese, Cambodian, and Laotian sativas are more prone t grow into hermaphroditic adults.

Nepalese sativas can grow oversized leaves and tall leggy plants that produce sparse, late-blooming buds, but other strains from this region develop into short, compact plants that bloom earlier. Tetrahydrocannabinol (THC) production and potency is often quite high, but can also be second-rate.

Hemp strains are all considered to be Cannabis sativa. Hemp, affectionately referred to as “rope”, is Cannabis sativa grown for fiber content. Hemp is often seeded and contains very, very low levels of THC.