Posted on

how to tell male and female cannabis seeds apart

Branches grow out of the main stem and support fan leaves and buds. Growers often train a cannabis plant by topping branches to create more bud sites.

Male cannabis plants grow pollen sacs instead of buds. Male plants are usually discarded because you don’t want them to pollinate the females, which will produce seeds—no one wants to smoke buds with seeds in it.

Cotyledon leaves

There are two types of hermaphrodite plants:

The space between nodes is called “internodal spacing” and will give you a sense of whether a plant will grow tall or short.

The pistil contains the reproductive parts of a flower, and the vibrant, hair-like strands of the pistil are called stigmas. Stigmas serve to collect pollen from males.

A single male pre-flower appears

Male pre-flowers are basically immature pollen sacs. When the plant starts flowering, they will grow and turn into bunches that almost look like grapes.

These tests only require a tiny amount of plant tissue (for example a small punch-out from a leaf, or a single cotyledon leaf), so it won’t hurt or slow down your seedlings to take a test sample!

Variability of Cannabis Plant Sex – How to Increase Ratio of Female Plants with Regular Seeds

Ok, now that you know what male pre-flowers look like, what do female pre-flowers look like?

Female Pre-Flowers

In this pic, you can see white pistils emerging from the calyxes. Female pistils are white and wispy, never green.

I’ve also noticed that sometimes (though not always!) the stipules on male plants seem more “leafy” and less “pointy” than stipules on female plants (the stipules are the green hair-like growths near where pre-flowers show up). However, this is just a generality, and should be used together with other factors to determine if a plant is male! There are definitely male plants with pointy stipules and vice versa, but it’s sort of a general difference.

For the most part, the average home grower wants female cannabis plants. The ladies are the ones that produce the fattest, most resinous and most potent flowers – aka buds. Male cannabis plants are only desirable if someone wants to breed cannabis and save seeds (which is a whole other topic for another day). Even then, the grower will want to spot the difference between the male and female plants and separate them early on, unless they want free cross-breeding and pollination between many types of stains.

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.

When to Sex Cannabis Plants

Until we can tell the sex for sure, we continue to treat the plants equally. We start our seeds in small 4-inch nursery pots. About two weeks after germination, we pot the seedlings up into an approximately two-gallon (trade size) “sexing pot” like these BPA-free nursery pots. This enables everyone to continue to grow in a happy and healthy manner for several more weeks*. Then, once we can surely tell the difference between the male and female cannabis plants, only the ladies move into their forever home – 15 to 25 gallon grow bags full of recycled organic living soil. To learn more about our soil recipe and how we maintain it, see this article.

Aside from the clear-cut flower differences, there are a few (potential) trending characteristics between male and female cannabis plants. In many cases, male cannabis plants tend to be more gangly. They may be tall, narrow, have fewer fan leaves, and longer spacing between branches – also referred to as greater inter-nodal spacing. On the flip side, female cannabis plants are usually more compact and bushy than males.

Not only are the males less desirable, but male cannabis plants interfere with the quality and production of your female plant. Males grow pollen sacks, and produce pollen. When a female cannabis plant becomes pollinated by a nearby male, her energy shifts into producing seeds.