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how to determine marijuana seed gender

Feminized seeds are highly desirable to most growers. They’re efficient. It is almost sure-fire that you’re spending your energy and resources raising ladies. However, some growers accept or even prefer regular (unsexed) seeds! We grow a little of both.

Our goal here today is to learn how to tell the difference between male and female cannabis plants early on, so you can get the males away from the females as soon as possible! It will help protect your lady plants – but also spare you the wasted time, resources, and energy of tending to male plants that you don’t intend to keep.

How are feminized cannabis seeds made?

Please keep in mind that these traits are not guaranteed, and shouldn’t be the only way to sex cannabis plants! Variations among strains and phenotypes can lead to all sorts of crazy things. The general plant structure simply may help give you a clue if you’re on the fence.

However, the culled males don’t need to go to waste! One option is to chop up the male plant and use it to mulch other plants – much like we do with borage, fava bean greens, yarrow, and comfrey. You could also juice the leaves, which are full of nutrients. Heck, you could even steep the plant material in water to create a natural fertilizer as we do with stinging nettle. Finally, I’m sure your compost pile will welcome the male plant with open arms. Or would that be… with open worms?

Like most things in nature, female cannabis plants have a biological drive to reproduce. After the deed has been done, she will sit back and relax. While a pollinated female cannabis plant WILL still develop decent size buds, they are usually lower quality and contain less THC and other desirable cannabinoids. Not to mention, they’ll be full of seeds. When left un-pollinated, a female cannabis plant’s flowers (buds) will continue to swell, develop more trichomes and become increasingly resinous. She is trying to get as sticky and large as possible to catch pollen in the wind. That sweet sinsemilla – aka unfertilized, seed-free cannabis.

Young cannabis plants first begin to demonstrate signs of gender, or pre-flowers, a month after germination while the plant is still in the vegetative stage. Photo by: Gina Coleman/Weedmaps

In the pre-flowering phase, the main giveaway of a female plant is the appearance of fine, white hairs known as stigmas protruding from tiny tear-drop shaped buds. Stigmas form part of the pistil, or the female reproductive organs, that are located at the nodes where the branches meet the central stalk.

Why do growers desire female plants?

Two signs indicate a plant is hermaphroditic. The first and most obvious sign is if the plant grows both male pollen sacs and female buds. The second sign is the appearance of anthers, known colloquially by growers as bananas or “nanners.” Anthers have a curved shape, are typically yellow or lime-green, and appear among buds. Unlike regular male pollen sacs, these anthers can fertilize the female plants as soon as they emerge, so they must be immediately trimmed or removed to protect a female crop.

There is no way to determine the gender of a cannabis seed unless you’ve purchased feminized seeds from a reputable grower. Feminized seeds almost exclusively produce female plants; however, you should still check your crop to ensure no rogue male plants have snuck in. Feminized seeds can also become hermaphrodite plants in times of stress, particularly if they come from dubious genetic lines.

Male plants don’t produce buds. The male sex organs of the cannabis plant instead produce pollen sacs that are designed to fertilize the female bud and form seeds. Seedy female buds are undesirable as they provide lower-quality cannabis. It’s essential to remove the male and hermaphroditic plants from a crop as soon as possible to protect the quality of the female buds.