Gender Determination for Growing Marijuana Plants


Determining the gender of your marijuana plant is an essential part of growing. Only female marijuana plants will produce the high quality smokable buds desired. Male plants grow pollen sacs instead, which eventually burst and spill forth pollen. This can be useful for growing seeds, but not for growing high quality bud. When growing marijuana plants, it’s the female that we want, but unless we are specifically purchasing female seeds, we will need to understand how to perform an analysis for gender determination.

V-shape calyx indicates a female cannabis plant.

A plant’s gender can be identified both during the ‘vegetative’ stage and the ‘flowering’ stage. The ‘vegetative’ stage is when the plant is still growing and developing and the ‘flowering’ stage occurs when it reaches adulthood and buds or pollen sacs sprout forth.

Gender Determination at the Vegetative Stage

Four to six weeks after a seed has been planted, during the vegetative stage, gender determination is possible by looking at a plant’s internodes, the place where the leaf stem meets the main stem. Usually around the fourth or fifth internode up the plant, a pre-flowering begins that allows a visual analysis to decide the gender of the organism.

Telltale Gender Signs

In female plants, a pear shaped ball called a calyx develops and 2 wispy white hairs called pistils grow forth from the calyx in a V shape. These hairs are never green, they are only ever white. This plant will flower high quality buds. Make sure you give your plants enough time to grow the white wispy hairs, before deciding they are male and removing them from your crop. The female calyx can sometimes look like the beginning of a pollen sac and needs a few days to grow pistils.

Pollen sacs indicative of a male marijuana plant.

In male plants, balls form in the internodes but they have no white wispy hairs. The balls form pollen sacs and will eventually fill with pollen and burst, spreading the pollen. These plants are not generally used for smoking and when smoked, generally produce headaches. One male plant can be used to pollinate your female plants if you intend on breeding seeds, but otherwise these plants can be removed from your crop.

Occasionally hermaphrodite plants may also grow in your crop. These plants contain both the male and female parts. They will grow both pollen sacs and the calyx and pistils. These produce a weaker bud and also should generally, also be removed from the crop.

Gender Determination at the Flowering Stage

Sometimes gender determination is difficult in the pre-flowering stage. If this is the case for you, the adult ‘flowering’ stage is the best time to assess the gender of your plant. This stage begins 2-3 weeks after your plant has been switched to 12 hours light, 12 hours dark. At this stage gender determination is clear, based on whether the plant is growing buds (female) or balls (male).

TIPS: Female plants are more likely to grow when nitrogen levels are increased and potassium levels are decreased. Also it is advised that only blue light and low temperatures┬ábe used in the first two weeks of the ‘vegetative’ stage.


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