Sexing Marijuana Plants – How to see if your cannabis plant is male or female


Sexing cannabis plants is critical to maximizing your harvest. This article will teach you how to sex your marijuana plants (even before they bloom) when they are in bloom, and how to induce flowering.

Sexing marijuana plants helps separate male plants from female plants. Only when the flowering cycle has begun can it be determined whether cannabis plants are male or female.

Cannabis begins to bloom when it receives 12 hours of light and 12 hours of uninterrupted darkness in each 24-hour cycle.

Once this light cycle (or photoperiod) is initiated, the plants will enter pre-bloom as they grow in size as the branch structure prepares to carry and support flowers.

How can you tell if your plant is male or female before flowering?

During pre-flowering, which usually takes around 10 days, it is still not possible to identify the sex of the plant. The first flowers should be visible within two weeks.

Female cannabis plant

Male cannabis plant

The use of feminized seeds or automatic seeds should eliminate this process as they are bred to produce plants that will flower as women.

Induction of flowering for sex of marijuana plants

Indoors, the grower decides when to change the photoperiod and induce flowering. This is achieved by simply setting the timers on the lights.

Outside, the grower will have to wait for the natural hours of daylight to drop to around 12 per day. When exactly this happens, of course, depends on the location. In Northern Europe this happens around mid to late July.

It is possible to induce flowering outdoors by exposing the plants to 12 hours of daylight each day, then covering them or bringing them inside.

However, this must absolutely happen every day. If the dark periods are interrupted by light, this can adversely affect the plants and return them to a vegetative state.

  • Disclaimer:

    Cannabis growing laws and regulations differ from country to country. Sensi Seeds therefore strongly recommends that you check local laws and regulations. Do not act contrary to the law.



Robert Dunfee