The gender of a cannabis plant can be determined throughout its life cycle. The stages tend to be short in duration, so determining the difference at the optimal time is sometimes challenging. Distinguishing the sex of a cannabis plant is often crucial to successful propagation and cultivation of the species because breeding both genders in close proximity can cause the whole crop to go to seed too quickly, preventing the harvest of intermediate axillary buds of the plant. It is important to determine the male and female plants so that they can be separated at the right times for the purpose of cultivation. Watching the whole cycle of a crop of cannabis helps you to distinguish the gender at each of these stages for identification with the next crop.
Note the pattern of leaf distribution in each plant of the crop. The plant grows up to 40 inches high, starting from its seedling or clone and then developing successive nodes on the initial stalk. The first indication of sex is visible when the leaves begin to sprout at these nodes. Female plants have significantly more branching and leaf growth than their male counterparts, which display only a few leaves in a seemingly random pattern. Determining the plant’s gender at this early stage in the reproductive process allows you to separate male from female plants and ensure that the crop does not go to seed.
Note the shape of the flowers when they bloom. This is the stage in which the gender difference is most clear. Male plants develop tight clusters of ball-shaped flowers, whereas female plants produce V-shaped pistols that are covered in patches of fine white hairs.
Watch the behavior of the plants after they flower. Both of male and female plants look very similar until after they produce their flower. At this stage, the male plants have successfully engaged in their reproductive capabilities, tend to turn yellow and eventually die. Before they start to change color, the male plants can be harvested for their fiber. The female plants, in contrast, remain green for about a month after they produce their flower; this is the time when the seed ripens.
- Consult a botany field guide for a visual representation of leaf distribution.