Grow More Females from Seed

Marijuana Horticulture

by Jorge Cervantes

Environmental factors start influencing sex the moment the seedling has three pair of true leaves (not counting cotyledons). Environmental factors that influence sex determination of cannabis include but are not limited to:

Increasing the level of nitrogen makes more female plants. Lower the nitrogen level too create more male plants. Increase the level of potassium to increase male tendencies; lowering potassium eves encourages female plants. A higher nitrogen level and a lower potassium level for the first two weeks increases females.

Low temperatures increase the number of female plants. Warm temperatures make more male plants.

High humidity increases the number of female plants. Low humidity increases male plants.

Low grow medium moisture increases males.

More blue light increases the number of female plants. More red light increases male tendencies.

Fewer hours of daylight (e.g. 14 hours) increases the number of females. Longer days (e.g. 18 hours) make more male plants.

Stress: any environmental stress tends t yield more male plants when growing from seed.