Male vs. female cannabis: How to determine the sex of your plant
In the world of plants, reproduction can happen in a variety of ways. Monoecious plants produce two different types of flowers on the same plant, and hermaphrodite plants grow single flowers that have both male and female reproductive organs.
Cannabis is a dioecious plant, meaning male or female reproductive organs appear on different plants.
With cannabis, females are usually isolated away from males—introducing males into a garden will result in pollination, causing females to create seeds.
This is important for a breeder to achieve new genetics, but most growers remove the males to allow females to produce seedless buds, also called sinsemilla. These are the resinous buds that appear on the store shelf; they all come from female plants.
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Seeded buds are generally regarded as low-quality cannabis. When seeds are present, the smoke is harsh and unpleasant.
Female genetics can be guaranteed by obtaining clones and feminized seeds. If, however, you’re working with regular seeds and are unsure of your seed’s sex, knowing how to determine the sex of your plant is vital to developing new genetics, gathering seeds, or growing sinsemilla.
Sexing cannabis plants is easy. Let’s see how to tell.
Check out these additional resources for more info on cannabis seeds:
How to determine the sex of a cannabis plant
Female cannabis pre-flowers grow as tiny bracts with hair-like stigma peeking out. Male plants produce small, round balls at the nodes. (Amy Phung/Leafly)
Cannabis plants show their sex by what grows in between their nodes (where leaves and branches extend from the stalk). Pollen sacs will develop on a male plant to spread seeds and stigma will develop on a female to catch pollen. You can see these differences weeks before they actually start serving their purposes in the reproduction cycle. These are known as “pre-flowers.”
Pre-flowers begin to develop four weeks into growth, but they may take a little longer depending on how quickly the sprouting phase occurs. By the sixth week, you should be able to find the pre-flowers and confidently determine the sex of your plant.
Pre-flowers can initially be extremely small and hard to identify with the naked eye, but you can use a magnifying glass to get a better look. Examine the nodes of the plant and look for either the early growth of small sacs on a male, or two bracts on a female, which will eventually produce the hair-like stigma.
Though there are other methods to determine what sex the plant is, examining pre-flower formation is the most reliable.
Removing males early on is important for two reasons: it frees up space in your garden so females can grow bigger and stronger, and it prevents males from pollinating females.
What are hermaphrodite cannabis plants?
Hermaphrodite cannabis can express both sex organs and self-pollinate. (Amy Phung/Leafly)
When a female plant develops both male and female sex organs, it is considered a hermaphrodite. This means your cannabis plant is now capable of producing pollen that can pollinate your entire garden. “Herming out,” as some call it, is something that generally happens when a plant becomes excessively stressed. Some plant stressors include:
- Plant damage
- Bad weather
- Nutrient deficiencies
There are two types of hermaphrodite plants:
- A plant that develops both buds and pollen sacs
- A plant that produces anthers, commonly referred to as “bananas” due to their appearance
While both result in pollen production, true hermaphrodites produce sacs that need to rupture, while anthers are exposed, pollen-producing stamen.
Because this occurs when cannabis is under stress, it’s important to monitor plants after they have been exposed to stressors—indoors: high temperatures or light leaks are often the cause; outdoors: a snapped branch might be repaired and then turn into a hermaphrodite.
The other primary cause of hermaphrodite plants lies in the plant’s genetics. A plant with poor genetics or a history of hermaphrodite development should be avoided to protect your garden. If you notice any pollen sacs or anthers at any point, remove the plant from your garden immediately to prevent pollination of female plants.
If you’re interested in pollinating portions of your crop, remember that pollen is extremely potent and very good at traveling. Keep your males intended for pollination far from your garden space and work carefully with that pollen.
This post was originally published on September 19, 2017. It was most recently updated on February 11, 2020.
Determining the sex of your cannabis plant is vital to achieving your growing goals. Luckily, sexing cannabis plants is easier than one might think.
Can You Tell if a Cannabis Seed is Male or Female?
Friday August 17, 2018
W hen it comes to growing cannabis, sex is important. Not that kind of sex! We’re talking gender, as in being able to discern male from female. The reason for this is simple enough: only female seeds produce flower, also known as the buds you might have in your stash as we speak.
When it comes to growing cannabis, seeds can be male, female or hermaphrodites. Females produce the resin-secreting flower, and males make small sacs of pollen near the base of the leaves. Over the years, cultivators have learned that un-pollinated females (remember, males produce pollen) continue to make resin and flowers that have not been pollinated are much more likely to produce high-potency cannabis. But is there a way to know if a seed is female before growing?
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Determining if a Seed is Male or Female
If what you’ve got is a handful of seeds, it’s pretty much impossible to tell which ones are male or female. The only way true way to tell the plant’s gender is to plant some seeds, then wait. After a period of several weeks, it will begin to pre-flower, or form a small bud in the crux of a branch. One of the first signs your cannabis plant is female is the appearance of pistillates that are wispy and generally white in color.
If you’re looking for more precise, science-based methods to tell your plant’s gender, there are several labs that can sex your plant right after germination – eliminating the lengthy (usually around 6 weeks) wait to learn its gender. Portland, Oregon start-up Phylos Bioscience is in the business of studying cannabis genetics, and they sell a “plant sex kit” that’s pretty simple to do, even for the not scientifically-inclined. Simply press a cotyledon, or embryonic leaf, onto the kit’s filter paper and send it to their lab. They then test the leaf for the “Y” chromosome to determine its gender, just as would happen for a human male.
What are Feminized Seeds?
While it’s basically not possible to determine the sex of a seed from a random bag of seeds, a practice known as feminizing is becoming quite popular. Feminized seeds are selectively bred to produce female plants, however, some growers do worry about some feminized seeds turning into hermaphrodites.
Despite the potential for hermies, if growing cannabis is more hobby than full-time endeavor, and you want to guarantee you’ll have some consumable product, knowing your seeds are female from the beginning is probably your best bet.
There are many companies that sell feminized seeds, but, buyer beware, do your research to make sure the seller is reputable, especially if purchasing online. Thanks to modern technology, most feminized seeds from reliable brands will be 100% female as advertised – but that doesn’t mean there aren’t people selling low-quality seeds out there.
Methods for Feminizing Cannabis Plants
If you have some experience growing cannabis and would like to bend a crop to your will to ensure that the seeds will be female, there are a few feminizing methods you might try. One such technique is to literally stress out a healthy female plant by interrupting the light cycle during flowering, called Rodelization Feminizing.
In the colloidal silver feminizing method, distilled water is mixed with pure silver and sprayed on female plants. This method works best when the plants are flowering. This results in pollen sacs being formed, which will allow the seeds to produce female plants.
Feminizing via the silver thiosulfate technique involves carefully selecting a nearly mature female plant, then spraying it with 50/50 mix of sodium thiosulfate and silver nitrate. This triggers a gender change, from female to male. Place this plant back with the others to pollinate other female plants, and female seeds are created.
How Important is Your Plant’s Sex?
How much time you want to spend figuring out the sex of your cannabis plants really depends on how much time and energy you’d like to devote to growing your own marijuana. If you are a medical cannabis patient or caregiver, for example, and need to know what kind of cannabis you are getting every time, buying feminized seeds from a trusted seller is the way to go. But, if you have some time, consider yourself a green thumb, and want to experiment with your grow, you could simply plant your seeds and see what comes up. Happy growing!
What are your thoughts on feminized seeds? If you’ve used them before, how did it go? Share your experiences in the comments below!
Erin Hiatt is a New York City-based writer who has been covering the cannabis industry for more than six years. Her work – which has appeared in Hemp Connoisseur Magazine, PotGuide, Civilized, Vice, Freedom Leaf, MERRY JANE, Alternet, and CannaInvestor – covers a broad range of topics, including cannabis policy and law, CBD, hemp law and applications, science and technology, beauty, and psychedelics.
If you're interested in growing cannabis, determining the sex of your plant is a critical aspect in the cultivation process. Learn whether or not you can tell if a marijuana seed is male or female and more information about feminized seeds.