Cannabis Sensei

Sexing Marijuana Plants: How to Tell Males & Females Apart

By Jake Willhoite · · Updated

how to sex marijuana plants
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When I was about to become a cannabis grower, I didn’t even know I was supposed to tell the differences between male and female marijuana plants.

Then I found out, and it was kind of intimidating; I didn’t want to mess up my harvest either! With a few years of experience under my belt, I will help you overcome that rookie fear and get the most out of your harvest.

In this article, we’ll talk about sexing marijuana plants, how to tell the males from the females, and everything else you need to know about your plants’ sex.

First, check the law. Home growing is legal only in some states, with limits; California, for example, lets adults 21 and older grow up to six plants. Marijuana is still a Schedule I drug under US federal law, outside a 2026 rescheduling rule that covers only FDA-approved and state-licensed medical products.

The Importance of Sexing Marijuana

Cannabis is a dioecious species. That means plants normally carry either male or female flowers, though some plants end up with both (more on hermaphrodites below).

Why Know The Difference Between Male And Female Marijuana Plants?

Most home growers want high-quality, seedless buds.

Cannabinoids are concentrated in the resinous trichomes on female flowers, which is why growers want female plants.

That’s why we need to remove male plants as soon as we identify them, before they release pollen. “Well, I’ll just let them sit around and use the female plants,” you might say. No!

Why Do We Need To Remove Male Plants As Soon As Possible?

When you have both male and female plants in your grow room, they’re wired to reproduce.

Once female plants receive pollen, Oregon State University Extension notes that the flowers decline as the plant sets seeds. You end up with seedy buds instead of the seedless flower most growers want.

On top of that, male plants take up space, light and nutrients that your females could use.

Without further ado, let’s get down to business.

Male Cannabis Plants

In the early stages, male pre-flowers look like small, round balls at the nodes, where the leaf stems meet the main stalk. These grow into pollen sacs.

As flowering goes on, male flowers hang in loose clusters on slender stalks, a bit like tiny bunches of bananas. When they open, they release pollen.

close-up of growing male marijuana plant with pollen sacs on stem

Female Cannabis Plants

Instead of pollen sacs, the female plants start as individual pistils or white hairs (occasionally, these may be yellow or pink-tinged) protected at the base by a membranous layer, the calyx.

As flowering progresses, more and more of these pistils will form until they produce the sticky clusters that make up the bud.

top of growing female marijuana plant with pistils

Hermaphrodite Cannabis Plants

Hermaphrodite plants show both male and female flowers. They can pollinate themselves and the rest of your crop.

Some strains are more prone to this than others. Stress can also trigger it: OSU Extension notes that genetically female plants can produce pollen structures at any point in the season, possibly due to environmental stress.

You can’t change a strain’s genetics, but you can keep stress low and check your plants regularly through flowering.

Common stressors to watch:

  • Disruption in flowering photoperiods (light leaks, etc.)
  • Temperature dropping too low or going too high
  • Too much or too little water
  • Incorrect fertilization
  • pH imbalance
  • Physical stress (training during flowering stage)

How to Sex Marijuana Plants

There are three main ways to determine the sex of your cannabis plant.

1. Visual Inspection

The easiest and least expensive way is to spend time with your plants and inspect the nodes closely. Pre-flowers often show up several weeks into growth, though timing varies by strain and conditions. A jeweler’s loupe helps.

Before any flowers form, males and females look the same. OSU Extension says vegetative male and female plants are visually indistinguishable, so don’t rely on height or leaf shape alone.

Once flowering starts, males tend to stretch and become slender at the top, and they often show their sex before females.

Females show fine white hairs (pistils), sometimes tinged orange or pink, coming out of a small calyx. These develop into dense, resinous buds.

2. Forced Flowering

Forcing cuttings to flower is another way to learn each plant’s sex. It works best for small grows, since it takes extra time and space.

Take a labeled cutting from each plant, root it, and give the rooted cuttings 12 hours of uninterrupted darkness a day in a separate space.

Once the cuttings show their sex, usually within a couple of weeks, you can remove the matching male plants from your grow.

3. Chemical Testing

The third method costs more but works before any flowers appear. OSU Extension notes that to determine the sex of hemp before flowers are present, tissue samples must be sent for DNA testing.

These lab tests need only a small piece of leaf, so they don’t harm the plant. Check the lab’s instructions for how old seedlings should be before sampling.

Regular Seeds vs Feminized Seeds

I know, that’s a lot of info for someone who’s just starting out. The good news is that there’s an easier way.

If you want to mostly skip the sex-determining process, you can learn how to feminize seeds or buy feminized seeds from a legal, trusted source.

What are feminized seeds?

Feminized seeds come from a female plant that was made to produce pollen. The goal is all-female offspring, but OSU Extension describes the result as “mostly female plants,” so keep scouting for males and hermaphrodites.

They are popular with beginners because they cut most of the guesswork.

Are regular seeds better than feminized seeds?

It depends on your needs. Feminized seeds cost more, but they save space and cut the risk of pollination. You’re also limited to the strains sellers offer in feminized form.

Regular seeds produce a mix of males and females. OSU Extension says seed from open-pollinated fields typically gives about 30% to 50% male plants, so plan for extra plants and culling. In return, you can use the males to breed your own strains.

You’ll need to learn how to tell the sex of your marijuana seeds before they become full-grown plants.

Other Uses of Male Cannabis Plants

Culling male plants doesn’t mean males are useless.

Their main use for home growers is breeding: keep a male in a separate space to pollinate chosen females and make your own seeds, where the law allows.

Male plants also hold nutrients, so you can chop them and add them to your compost pile instead of throwing them out.

Wrapping Up

It’s vital to spot male plants on time if you want seedless buds. Moving them to a different corner of the same grow room is not enough to avoid pollination.

Pollen travels on air, insects and clothing, and there is no known distance that will completely eliminate the chance of pollination via wind. If you keep males for breeding, use a separate room, and change clothes after handling them.

Happy growing!

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