Ask the Budding Botanist: how can you tell between a male and female weed plant?

With more states legalizing cannabis, interest in cultivating the plant continues to rise. And while cannabis may grow like a weed, it takes time, care, and consideration to craft top-shelf buds.

GreenState knows that people have lots of questions about growing cannabis. To help take the guesswork out, professional cultivator Kurt Kinneman, owner of Kinnektion Farms and horticultural engineer at AI Grow, is here to answer your budding queries. From seed to smoke, GreenState has you covered.

Question: how can you tell a female weed plant from a male—and why does it matter?

When you start a cannabis seed, it can either be a male or female plant. The female plant produces the large, smokable buds we all know and love. The male cannabis plant produces the pollen that would “impregnate” the female cannabis plant. 

Female cannabis plants must be kept separate from males. If the females were to be pollinated, the buds would become seeded. Production of active compounds like cannabinoids will go down as the plant will want to spend more of its energy growing seeds. And while you could always take out the seeds and smoke the bud, it’s a less-than-ideal scenario.

How to tell the difference between male and female weed plant

Checking the sex of a cannabis plant must be done as early as possible in the growing cycle. This way, any risk of pollination is reduced.

Male plants will tend to have thicker stems, and the plants will grow taller with fewer sets of leaves. It is important to look for signs of early flowering because male plants tend to flower faster than female plants. Female plants will typically be bushier and have less space between leaf sets, which are the plant nodes where leaves and vegetative flower growth begin. 

Start looking for signs of the plant’s reproductive organs at the plant nodes, where the stem of the leaf meets the main stalk. These new growths will typically begin forming around mid-July when growing outdoors and after one to two weeks into the flower state indoors.

After two to three weeks of flower growth, the plant’s reproductive organs will become more clearly defined. The male pollen sac will form a claw-like structure that will have five distinguishable sides. These structures can develop and open quickly, releasing pollen into your garden. 

It is important to identify and remove male plants from the garden as early as possible to prevent them from releasing any pollen. The female cannabis plant will form what’s called a pistillate calyx at the plant nodes, which will have white, hair-like structures protruding from them. Seeing these white hair protruding from new flower growth is a sure sign you have a female cannabis plant.

When four to six weeks of flower growth have passed, the female cannabis plant will have stopped increasing growth between the nodes and will only focus on pistillate calyx growth. Their white hairs can easily identify these. Plants will be producing leaves with fewer leaflets at this point, and some of the white hair may be starting to turn orange. 

After eight weeks of flowering, the female cannabis plant will be solely focused on growing the staminate calyx and the trichomes that protect it. The cannabis plant produces trichomes throughout its life cycle to help protect itself and its reproductive organs from the environment. The female cannabis plant can continue to grow for over 12 weeks while the flowers mature, but they typically mature within eight to nine weeks of flower growth. 

Hermaphroditism in cannabis plants

Weed plants can grow both female and male reproductive organs. Stresses such as under watering, high heat, nutrient imbalances in the growing media, or other environmental stresses can cause a plant to grow male and female flowers. 

Poor genetics can also cause hermaphroditism to occur. It’s important to get female cannabis seeds from reputable breeders to ensure hermaphroditic genetic traits are being passed on. Breeders like Humboldt Seed Co., Blimburn Seeds, Royal Queen Seeds, and Tangled Roots are great options.

Identify your female weed plants ASAP

Distinguishing a female weed plant from a male is all about visual inspection. Female plants will start to grow white hairs at the nodes. Male plants will mature quickly, with a tiny ball forming instead. 

Begin checking the nodes of your plants early and often, typically within a week of entering the flower stage. Remember to remove male plants from the garden as soon as they are identified to prevent female plants from becoming impregnated and producing seeds! 

This article was submitted by a guest contributor to GreenState. The author is solely responsible for the content.