Sexing Cannabis – How to distinguish Male vs Female Marijuana Early

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Male cannabis plants are marked with flags in this field owned by CBD grower, Steve Rogers from Singing Pig Farm near Salem, Oregon. He will remove the male plants from the field and add them to the compost pile. Learning to identify male and female cannabis plants early is essential for a heavy harvest.

In nature cannabis plants grown from seed are either male or female. These cannabis plants and seeds are often called “regular”. The average male:female ratio for regular seeds is 50% male and 50% female. Regular and regular auto-flowering cannabis require sexing to distinguish male plants from female plants. Once the sex of the plants is distinguished, male plants, unless used for breeding, are removed from the garden so that pollen from flowers do not pollinate females. And male marijuana plants contain few cannabinoids. Unpollinated female plants are desirable because they produce more and higher levels of cannabinoids including CBD and CBD.

Sexing regular cannabis discovers whether plants are male or female. Regular cannabis can be sexed during the pre-flowering growth stage. Male plants can be removed from the garden before they release pollen and to allow more growing room for females.

The easiest way to distinguish male from female cannabis grown from regular seed is when marijuana plants are about two months old. This is when cannabis pre-flowers appear on marijuana plants.*

*Feminized cannabis plants should not need sexing. Feminized cannabis plants have been treated or altered to produce all female plants. However, feminized cannabis plants have a higher insidense of intersexuality (AKA hermaphrodite) when both male and female flowers appear on the same plant. Always be on the lookout for male cannabis flowers on female plants. If a few male flowers appear, they are easy to pinch off and remove before pollen releases. If many male flowers appear, remove and issolate the plant from the garden so that it does not pollinate other females.

What is the difference between regular, feminized, photoperiod and auto-flower cannabis?

Regular cannabis – individual plants with either male or female flowers. Regular cannabis can be photoperiod or auto-flower.

Feminized cannabis – are treated and altered so that only female flowers grow. Feminized seeds can be either photoperiod or auto-flower.

Photoperiod cannabis – typically requires 12-hours of complete darkness and 12 hours of light to flower. AKA Short day plants. Photoperiod cannabis can be regular or feminized.

Auto-flowering cannabis – flowers about three weeks after seed germination regardless of day and night length. Auto-flowering cannabis can be regular or feminized.

When does cannabis pre-flower?

Regular and feminized pre-flowers on cannabis grown from seed appear about the fourth week of vegetative growth, eight weeks from seed emergence. Pre-flowers on regular and feminized cannabis generally appear between the fourth and sixth node from the bottom of the plant. Cannabis plants are normally either all male or all female. Cannabis is predominantly dioecious with imperfect flowers – satminate “male” and pistillate “female” flowers occur on separate plants. Each sex has its own distinct flowers. Pre-flowers will distinguish a plant as male or female.

What do male cannabis pre-flowers look like?

Little male cannabis flower pods full of pollen are developing on the stem at the base of a leaf and a new growing shoot. A low-power hand-held microscope makes identifying male flowers easier. Keep a vigilant eye out for the little male flowers. When you spot them at first, watch them develop for a few days so that you become very familiar with the way they look. Make sure to pinch off the little male flowers with your fingernails.

What do female cannabis pre-flowers look like?

Female stigmas grow from seed bracts and appear as a pair of white fuzzy hairs. The first female pre-flowers appear after about 8 weeks of vegetative growth under normal conditions.

When does auto-flowering cannabis pre-flower?

Auto-flowering cannabis starts flowering after about 21-25 days of chronological growth. Pre-flowers set and soon flowers develop. After 60-70 days the flowers are ready for harvest. The entire auto-flower plant life cycle, sprouted seed to harvest, is complete 70-90 days regardless of daylength. Branches on auto-flowering cannabis plants are often fairly close together on the stem.

What is a hermaphrodite cannabis plant?

Photo courtesy Second Generation Genetics.

Intersex cannabis is often called hermaphrodite marijuana. Intersex plants contain both male and female flowers on the same plant. Male flowers shed pollen that fertilizes female flowers. Once fertilized, female flowers develop seeds in a few weeks. Seeds produced are not stable genetically and will be of inferior quality. I do not advise to plant seeds from an intersex plant.

Intersex plants typically have unstable genetic traits. They will continue to produce male and female flowers on the same plant. The pollen from male flowers pollinates female flowers of all nearby plants. Once pollinated female plants stop rapid cannabinoid-rich resin production and put their remaining resources into seed production.

What does a male cannabis flower look like?

Flowers on this male plant should open in less than a week. Once open male pollen will pollinate female flowers. Growers remove and destroy the males (or use them for breeding stock) because they have negligible levels of cannabinoids (THC, CBD, CBG, etc.) and produce little foliage.

Male cannabis plants like this Diablo from Spain, produce a fraction of the cannabinoids that female marijuana plants produce. Male marijuana flowers also pollinate female cannabis flowers which causes them to produce seeds and less cannabinoid-potent (CBD and THC) resin.

Botanical drawing of male cannabis flowers.

This botanical image of a male cannabis plant shows each flower part including the location of the pollen in the male flower.

What does a female marijuana flower look like?

Cannabis typically flowers from 6-12 weeks. This beautiful early flower image is courtesy of my friend Macky in the UK. Female plants are cultivated for their high cannabinoid content, including CBD, THC and more recently, CBG.

Female cannabis flowers are desirable and male marijuana plants are undesirable. Female cannabis flowers contain about 10 times more cannabinoid-potent resin (CBD or THC) than male plants. Unpollinated female plants (sinsemilla) develop more resin than seeded plants.
Female marijuana plants grow much bigger and stronger than male plants.

Botanical drawing of female cannabis flowers.

This botanical drawing of a female cannabis plant shows each flower part including the location of the fertilized seed inside the seed bract.

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