Comparing genders is a dangerous topic in most circumstances, but among Cannabis plants there is little argument that the females are the most sought-after. Only female marijuana plants produce flowers with an abundance of trichomes, the glands that generate the resins that give marijuana its recreational and medicinal effects. Male plants contribute pollen necessary to produce seeds in female flowers, but this is often not wanted. Creating seeds diverts the females’ resources from creating the maximum amount of cannabinoids, and the seeds themselves “dilute” otherwise potent buds. When growing high quality cannabis for medicinal or recreational use, most growers aim to cultivate entirely seedless female cannabis plants, known as sinsemilla.
To prevent seed production, strict segregation of the sexes is required. Unlike some other flowering plants which require animals to pollinate them, Cannabis pollen is carried on the wind. A single male plant in a room with females will be able to pollinate most or all of the female flowers. By isolating the female flowers from any male pollen, no seeds will grow. Desirable varieties of female plants can be propagated through cloning, without the need for seeds.
Luckily for growers, Cannabis plants have a visual tell that allows a plant’s sex to be known, usually before the threat of pollination has arrived. During the initial vegetative growth period, male and female plants will develop different structures near the nodes where the leaf stems meet the stalk. Male plants grow a small cluster of bell-shaped objects that will eventually form the male flowers which release pollen, while females develop a calyx (small, wrapped, leaf-like and teardrop shaped) with two hair-like protrusions from inside the calyx called pistils. As soon as these hairs are visible, the plant can be confirmed as a likely female. Occasionally, plants will be a hermaphrodite with both male and female flowers can arise, but they are relatively rare and will eventually be given away by the presence of pollen-releasing structures. Even strict female plants gen generate male flowers if they are severely stressed; this is an evolutionary survival strategy that allows cannabis plants to reproduce in the absence of male plants if necessary.
By identifying and segregating the Cannabis genders, you too can grow seedless, high-quality buds!