Can You Tell if a Cannabis Seed is Male or Female?
W hen it comes to growing cannabis, sex is important. Not that kind of sex! We’re talking about the sex of the plant, and whether it is male or 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.
- Cannabis Seeds Explained
- What to Look for When Buying Cannabis Seeds
- How to Germinate a Bag Seed
- Understanding the Anatomy of a Cannabis Plant
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 as they grow, and flowers that have not been pollinated are much more likely to produce high-potency cannabis. This is the basis of all modern medical and recreational cannabis cultivation, so determining the sex of a plant is highly important. But is there a way to know if a seed is female before growing?
Table of Contents:
- Determining if a Cannabis Seed Is Male or Female
- What Are Feminized Cannabis Seeds?
- Methods for Feminizing Cannabis Plants
- Separating Male and Female Cannabis Plants
- How Important is Your Plant’s Sex?
Determining if a Cannabis Seed Is Male or Female
The straightforward answer is that, if what you’ve got is a handful of unmarked seeds, it’s pretty much impossible to tell which ones are male or female. The only true way to tell the plant’s gender is to plant a seed, then wait for it to mature.
After a period of several weeks, the plant 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. Male plants will instead produce pollen sacs that look rounded with distinct splits running lengthwise, a bit like a tiny crab claw. These are the structures that growers typically look for to determine a plant’s sex.
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 folks that aren’t 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 Cannabis 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 quite popular. Feminized seeds are selectively bred to produce only female plants.
While the process is very effective, it’s not perfect. There’s a chance that a small fraction of the seeds produced via the feminization method will sprout hermaphrodites, which are still capable of producing pollen.
Despite the potential for ‘hermies,’ 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 a 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.
Separating Male and Female Cannabis Plants
As anyone with seasonal allergies can attest, it only takes a little bit of pollen to have a big impact. The reason that growers are so intent on weeding out male cannabis plants is that a single pollinator can negate an entire potential harvest.
How? The reason is that once pollinated, cannabis plants will cease devoting energy to growing flowers and will tell the existing flowers to stop producing resin, which translates to making less buds and less THC. That energy will be devoted to producing seeds instead. Think of the plant as a battery with a set amount of power. When that supply is spent in one area, it won’t be available for another.
Now consider that a single male plant can spread its pollen to an entire room of females.
If a grow is accidentally pollinated, that means the resources that were spent to bring the plants to that stage — the water, soil, electricity, fertilizers, not to mention the price of the seeds themselves — will have been wasted growing weed that can’t be smoked.
All of those male plants will have to be carefully separated from the grow space and destroyed, or else the growers risk another disastrous accidental pollination. It takes minuscule amounts of pollen to pollinate a plant, so growers must take extensive precautions to eliminate potential contamination. In addition to helping mitigate other contaminants, this is one of the main reasons that many workers will don full-body suits when working in a grow room, ensuring that accidental pollen exposure is kept to a minimum.
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 to keep a reliable supply, buying feminized seeds from a trusted seller is the way to go. It may even be worth it to have your plants tested for sex before they mature. However, 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.
Erin’s work and industry insights have been featured on the podcasts The Let’s Go Eat Show, In the Know 420, and she has appeared as a featured panelist on the topic of hemp media. Erin has interviewed top industry experts such as Dr. Carl Hart, Ethan Nadelmann, Amanda Feilding, Mark A.R. Kleiman, Dr. James Fadiman, and culture icons Governor Jesse Ventura, and author Tom Robbins. You can follow her work on LinkedIn, WordPress, @erinhiatt on Twitter, and @erinisred on Instagram.
Marijuana plant anatomy
The cannabis plant has several structures, many of which we can find on any ordinary flowering plant species. Cannabis grows on long skinny stems with its large, iconic fan leaves extending out from areas called nodes.
Cannabis really stands out in its flowers—or buds—where unique and intricate formations occur: fiery orange hairs, sugary crystals, and chunky buds enveloped by tiny leaves.
Parts of the cannabis plant
Seeds are produced in female cannabis plants and carry the genetics of a male and female. Seeds need to germinate to sprout and will grow a taproot, which will become the main root that anchors the plant.
These are the first leaves to grow from the seed after germination. They usually come in pairs, and seeing them is a sign of successful germination and that your plant is on its way to growing healthy and strong.
The roots grow down from the main stalk of the plant into the soil. When growing from a seed, the main root is called the “taproot.” Roots are the lifelines of a cannabis plant, pulling water and oxygen into the plant so it can grow healthy and strong.
Mycorrhizae, a beneficial fungus, can be added to soil to improve root systems.
The main stem, or stalk, of a cannabis plant grows straight up from the root system and supports all lateral branches. The stem gives a plant structure and stability.
Often, growers will top, or cut off, the stem after about five nodes, which forces the plant to grow out laterally more, creating more bud sites.
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.
A node is a point at which a branch grows off of the main stem, or one branch from another branch. Fan leaves and buds can grow on some nodes, but not necessarily all.
When determining the sex of a cannabis plant, pre-flowers, or the beginnings of male and female sex organs, will appear at the nodes.
The space between nodes is called “internodal spacing” and will give you a sense of whether a plant will grow tall or short.
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
Fan leaves are the large, iconic leaves of the cannabis plant. They capture light for the plant and typically have little-to-no resin and are usually discarded when trimming.
Sugar leaves are the small, resin-coated leaves that buds form around. Sugar leaves are usually saved as “trim” during harvest and can be used for pre-rolls, extracts, and other cannabis products.
Also known as “buds,” the flowers of a cannabis plant are the fruits of your labor. They contain the cannabinoids and terpenes that get you high or offer health benefits. Flowers only grow on female cannabis plants and must be dried before consumption.
A cola, also called a “bud site,” refers to a cluster of buds that grow tightly together. While smaller colas occur along the budding sites of lower branches, the main cola—sometimes called the apical bud—forms at the top of the plant.
Bract and calyx
A bract is what encapsulates the female’s reproductive parts. They appear as green tear-shaped “leaves,” and are heavily covered in resin glands which produce the highest concentration of cannabinoids of all plant parts.
Enclosed by these bracts and imperceptible to the naked eye, the calyx refers to a translucent layer over the ovule at a flower’s base.
Stigma and pistil
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.
The stigmas of the pistil begin with a white coloration and progressively darken to yellow, orange, red, or brown over the course of the plant’s maturation. They play an important role in reproduction, but stigmas bring very little to the flower’s potency and taste.
Despite their minute size, it’s hard to miss the blanket of crystal resin on a cannabis bud. This resin is secreted through translucent, mushroom-shaped glands on the leaves, stems, and calyxes.
Plants originally developed trichomes to protect against predators and the elements. These clear bulbous globes ooze aromatic oils called terpenes as well as therapeutic cannabinoids like THC and CBD. The basis of hash production depends on these trichomes and their potent sugar-like resin.
Male vs. female marijuana plants
Cannabis is a dioecious plant, meaning it can be male or female, and the male and female reproductive organs appear on different plants. What’s in your stash jar now are the flowers of a female marijuana plant.
Female plants produce the resin-secreting flower that is trimmed down into the buds you smoke, and males produce pollen sacs near the base of the leaves. Male plants pollinate females to initiate seed production, but the buds we consume come from seedless female plants—these are called “sinsemilla,” meaning “seedless.”
Growers can ensure the sex of their plants by growing clones or the genetically identical clippings from a parent strain. Feminized seeds are also made available through a special breeding process.
How to determine the sex of a marijuana plant
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.
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.
Female marijuana plants
Females are the prizes of cannabis plants—they are the ones that grow the buds that we all know and love. Anytime you see a picture of a cannabis plant with buds, you are looking at a female plant.
Female cannabis plants receive pollen from males to produce seeds, which will carry on the genetics of both plants to the next generation.
However, cannabis is primarily cultivated for buds, not seeds, so the practice of growing sinsemilla, or “seedless” cannabis, is prevalent today: Females and males are grown separately, or males are even discarded, to prevent pollination. This allows female plants to focus their energies on bud production instead of seed production.
Males and females are usually only pollinated when crossbreeding plants or creating new strains.
Male marijuana plants
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.
Males are important in the breeding process, but that is generally best left to expert breeders. When pollinating females, males provide half of the genetic makeup inherited by seeds.
Because of this, it’s important to look into the genetics of the male plants. Their shape, rate of growth, pest and mold resistance, and climate resilience can all be passed on to increase the quality of future generations.
Male plants can also be used for:
- Hemp fiber—males produce a softer material, while females produce a coarser, stronger fiber. The soft fiber from males is more desirable for products like clothing, tablecloths, and other household items.
- Concentrate production—males do have some THC and can be psychoactive, but much less so than females. Small amounts of cannabinoids can be found in the leaves, stems, and sacs, which can be extracted to produce hash and other oils.
What are hermaphrodite cannabis plants?
The rare hermaphroditic plant contains both female and male sex organs. These plants can sometimes self-pollinate, but this is typically bad as it will create buds with seeds and also pass on hermaphroditic genes.
“Herming out,” as some call it, is something that generally happens when a plant becomes excessively stressed. Some stressors include:
- Plant damage
- Bad weather
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 hermaphrodite cannabis plants produce sacs that need to rupture; 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 its genetics—a plant with poor genetics or a history of hermaphroditic 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.
The Difference Between Male and Female Weed Plants
Cannabis plants have evolved enormously over the past couple of decades, mainly thanks to human kind. We’ve spent years combining different species from all over the planet. Every strain has its own specific characteristics, such as structure, type of buds, flavor and effects. When you combine male and female weed plants that are different strains, the new creation takes on characteristics from both, allowing us to create totally new plants.
One of the biggest achievements has been the appearance of feminized plants; after years and years of work, cannabis seeds can be created to have a 99% chance to be female. You need to know how to tell male from female plants when growing regular seeds, as you’ll only get actual psychoactive weed from the female flowers. Male plants pollinate female plants, which fills their flowers up with seeds so if you’re looking to make the most of your plants you’ll want to keep them away from each other. Hopefully we can help you to tell the difference between male and female weed plants by the end of this article; it’s not that hard, but if it’s not explained correctly it can be a bit confusing.
What’s the difference between male and female weed plants?
Male plants essentially produce pollen which is needed for cannabis plants to naturally reproduce; seeds occur when there are male plants in the mix. If you want to make your own seeds you will need a male plant However, if you’re growing regular plants and want to harvest flowers, we recommend getting rid of any males as soon as possible. You won’t be able to tell them apart until they begin to flower, which is when plants begin to show their sex. Male weed plants grow “balls” that open up to let their pollen out, ending up looking like a small bunch of flowers. You’ll need to get rid of them way before this happens. If they manage to release their pollen it’ll be too late. They can take up to three weeks to burst. If you’re still not sure how to tell them apart, male flowers do not have any pistils on them at all.
Female plants are basically what everyone is after when growing cannabis, as these are the ones that make buds, which is the part of the plant that contains the most THC. With just one male plant and a minuscule amount of pollen, your plants might end up filling their flowers with seeds. If you have male and female plants in the same growing area, the buds grown there will only produce seeds so you won’t be able to smoke any of it. You can tell females apart due to the fact that their flowers don’t fully close, they’re actually quite open and they produce little hairs called pistils. They’re incredibly easy to recognize, as the first thing they produce are their pistils, which male plants do not have at all.
Hermaphrodites are a type of plant that contains both male and female flowers, so they will produce buds but they will also pollinate those buds and the rest of your plants. Plants may naturally become hermaphrodites or be turned into one due to stress. Both female and male plants can turn. Thai strains are more genetically inclined to become hermaphrodites, although any strain can turn when stressed enough. There are many factors that can stress out your plants and end up turning them, such as extra light when they’re supposed to be in the night cycle, too much or not enough water, certain insects or pathogens, watering with cold water, or even a badly done transplant. Hermaphrodites aren’t the best type of plants to keep around, as they can produce buds but it’s definitely a risk because they might pollinate the rest of your plants. We recommend getting rid of them; it’s not worth it just for a little bit more weed.
It may seem confusing, but it really isn’t hard to tell male and female weed plants apart; they are quite different. Planting regular seeds has its benefits, as well as feminized has its inconveniences; you can get much larger yields with feminized plants as you’re guaranteed no male plants. Although, keep in mind that feminized seeds haven’t been through a 100% natural process to become female, which may affect the quality of your weed. This is why many cannabis connoisseurs haven’t made the leap from regular to feminized yet; they prefer to harvest slightly less yield that’s more potent and delicious.
However, feminized strains are a great option for rookie growers. Some seed banks, such as Nirvana seeds, Seedsman, Barney’s Farm, Ministry of Cannabis, Exotic Seeds or GB Strains offer amazing and affordable seeds that will provide fantastic results. If you are on a budget, check out our Cheap Seeds section. CBD Seeds are a great alternative for users interested on cannabis therapeutic uses.
Hemp Seeds, on the other hand, are perfect to produce sustainable fibers and make CBD products.