Sexing marijuana is done by several growers for the purpose of early identification and pulling out males from the garden so there is no chance for pollination to occur. For very potent buds with high THC level, do not allow pollination between male and female plants as this will reduce bud potency. Identifying the male weed plants as early as possible and taking them out from the grow area is the best way to do if you do not want pollination to happen.
It is easier to sex marijuana plants grown indoors before they enter the full flowering stage. Cannabis plants can be sexed in a month or so to allow you to identify males and cut them out. Know what are the signs that you are growing males or females in the garden during the pre-flowering period. Marijuana plants that are 28 days old from seeds can already express early pre-flowering.
Identifying the male marijuana plants
Male marijuana plants can be identified through the flowers they will produce. The flowers produced by males will include some balls. About 2 to 3 balls in clusters is an indication that you have a male weed plant. Check on the internodes of the plants and see what kind of flower is produced. Detach the males as soon as you notice them to avoid the release of pollens that can result to reduced potency of the buds produced by females.
Identify the female cannabis plants
Female marijuana plants are easier to identify than the males. Females will produce white pistils or colorless hairs. When these pistils are not pollinated by seeds produced by a male weed plant, they will change their color. The pre-flower of a female cannabis is pear-shaped that produces pistils. In some instances, some female preflowers may not show white pistils while pistillate preflowers are seen at the node, just between the branch and the stipule.
Preflowers usually appear after the 4th week of the vegetative stage. Sexing marijuana plants is not needed if you start your growing project from marijuana cuttings/clones or you are cultivating feminized pot seeds. But if you are growing marijuana and you start from seeds, knowing how to sex the cannabis plants during the early pre-flowering stage and taking the males out of the garden as early as possible will help you proceed to the next growing level faster. To see the preflowers, use a magnifying glass because it is quite hard to differentiate male from female preflowers by just merely looking at them using your naked eye.