Sexing Cannabis: How to Tell the Difference Between Young Male vs Female Cannabis Plants
Are you growing cannabis at home, but aren’t sure if your plants are male or female? Then you’ve come to the right place! This article is going to show you how to tell the difference between male and female cannabis plants to properly sex them.
In particular, I want to show you how we determine the sex of our cannabis plants while they are still quite young. It gets significantly more obvious as the plants begin to mature and flower. On the other hand, it can be a bit more tricky to sex cannabis plants in the early pre-flower phase, but it is definitely possible! We’ll also talk a bit about why it is important to determine the sex of cannabis plants, the difference between regular and feminized seeds, how we treat our plants up until the time we know their sex, and what to do with unwanted male plants.
If you’re new to Homestead and Chill, be sure to check out our other cannabis-related articles! We primarily grow outdoors, 100% organic, and aim to provide helpful information that is easy to follow – both for new and experienced growers alike. As a disclaimer, this article is intended for those who can legally grow cannabis at home.
Feminized vs Regular Cannabis Seeds
If you are growing from feminized seeds, you shouldn’t need to worry about sexing your cannabis plants all that much. While not 100% guaranteed, there is only a very slim chance that a feminized seed will produce a male plant. About 1% in fact. In all of our years growing, we have never had a cannabis plant grown from feminized seed turn out to be a male – though we only grow a handful of plants per year. Folks who grow hundreds of plants could potentially end with a rare male now and then.
Feminized seeds are highly desirable to most growers. They’re efficient. It is almost sure-fire that you’re spending your energy and resources raising ladies. However, some growers accept or even prefer regular (unsexed) seeds! We grow a little of both.
Why grow regular cannabis seeds? Well, maybe a particular breeder or strain you want to try only carries regular seeds. Some growers feel that the feminization process is unnatural, and prefer to kick it old school by growing regular seeds only. Some enjoy the gamble and challenge. Whatever the reason, when you grow cannabis from regular seeds, the odds of getting all lady plants are not in your favor. You will end up with some males. Therefore, you need to learn to sex your cannabis plants! Also, we always start several extra “regular” seeds – assuming a 50/50 chance that some will be culled because they are male.
How are feminized cannabis seeds made?
Curious about how feminized seeds are created? In a nutshell: most feminized seeds come from cannabis plants that have been treated and altered in a manner that inhibits male chromosomes. The most common method is to spray the plant repetitively (daily or more) with colloidal silver. Other chemicals and compounds can be used too, but are far less accessible. Colloidal silver is technically “non-toxic”, but you do not want to smoke it! Thus, the plant is sacrificial – used for the production of pollen and seeds only.
Repeated colloidal silver treatments cause repression of the plant’s ethylene, which is the stuff that creates male flowers. Instead, the treated female plant will grow pollen sacks full of FEMALE pollen (XX rather than XY). Then breeders use the female pollen to pollinate female flowers, resulting in the development of all-female seeds.
Another way to create feminized cannabis seeds is called rodelization. It is a more natural but unreliable method, and less frequently used by breeders. Near the end of a growing season, an un-pollinated female cannabis plant will sometimes produce pollen sacks in a desperate attempt to pollinate herself. That pollen can be used to try to create feminized seeds, but because ethylene hasn’t been repressed, may also result in male seeds.
Okay, back to sexing cannabis.
Why Sex Cannabis Plants? The Role of Male and Female Plants
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 strains.
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.
Like most things in nature, female cannabis plants have a biological drive to reproduce. After the deed has been done, she will sit back and relax. While a pollinated female cannabis plant WILL still develop decent size buds, they are usually lower quality and contain less THC and other desirable cannabinoids. Not to mention, they’ll be full of seeds. When left un-pollinated, a female cannabis plant’s flowers (buds) will continue to swell, develop more trichomes and become increasingly resinous. She is trying to get as sticky and large as possible to catch pollen in the wind. That sweet sinsemilla – aka unfertilized, seed-free cannabis.
When to Sex Cannabis Plants
Our goal here today is to learn how to tell the difference between male and female cannabis plants early on, so you can get the males away from the females as soon as possible! It will help protect your lady plants – but also spare you the wasted time, resources, and energy of tending to male plants that you don’t intend to keep.
Keeping in mind that every strain and grow set-up (e.g. indoors, outdoors, daylight hours) creates varying circumstances, most cannabis plants begin to pre-flower as early as 4 weeks after germination. By week 6, the pre-flowers begin to reveal their gender and you should be able to identify the sex using the tips to follow. Once the plants go into full flower (8 to 10 weeks on average, for a natural outdoor grow) the differences between male and female plants will be glaringly obvious. We’ll talk more about exactly what each sex looks like in a moment.
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.
*Note that our feminized seedlings go from a 4” pot to an 8” pot, and then more quickly into large grow bags, using less soil in the potting-up process.
This little girl (or boy) is far too young to tell, but needs to be potted up soon. The two in plastic pots in the background were determined to be male and culled the next day. The two on the left in grow bags are definite females (one from feminized seed, and one we sexed from regular seed).
How to Tell the Difference Between Male and Female Cannabis Plants in Pre-Flower
In order to correctly sex cannabis plants, you’ll need to become familiar with their anatomy in general. Both males and females produce pre-flowers and flowers in the junctions between stems or branches. The very first pre-flowers show up in the crook between the main plant stalk and a fan leaf stem (petiole), usually near the top of the plant. The good news is, the males usually begin to develop and show sooner than females. I guess the idea is that the dudes want to have their pollen ready and waiting for when the ladies join the party?
Look for plant pre-flowers at the higher stalk/branch junctions, as described above. If needed, use a jeweler’s loupe to get a better look! That is the same magnifying tool commonly used to examine trichomes and determine plant readiness for harvest. Then, locate the stipule, which is a leafy pointed flap that protrudes from the junction. Don’t confuse that for a pre-flower! The cannabis sex parts are located just behind the stipule. Behind the pre-flower sex parts, taller growth tips will emerge – future auxiliary branches that produce buds.
Identifying a Male Cannabis Plant
Very early, the male pre-flower (early pollen sacs) simply looks like a more round version than the female pre-flower part. It is often referred to as a “spade”, like the spade suit in cards – squatty with a bulbous bottom and very slight tip. As it becomes slightly larger, the male pre-flower resembles a ball at the end of a stick. The male pre-flower is called a staminate. Then, the staminate eventually develops into a long hanging sack of baby bananas – the pollen sacs. Hopefully you can ID and cull the males before they get to this stage.
A 4-5 week old male cannabis plant in our garden, showing his stick and ball. Note that this is a really early and obvious example. Most of the other males in this age group show a round ball, but protruding less and more nestled flat against the stalk.
A more advanced male pre-flower, courtesy of Dr. Weedly (We never let our males get this far to photograph)
Did someone order a banana hammock? The male flowers are about to open and shed pollen, if they haven’t already. Photo from Green Cultured
Identifying a Female Cannabis Plant
In contrast, the very early female cannabis pre-flowers are more ovate in shape: pear-like, but with a longer slender pointed tip. That is called her calyx. Extending from the tip of the calyx may be a pair of pistils, or white hair-like protrusions. However, please note that not every female cannabis plant in pre-flower produces pistils.
If you are still unsure of the sex of your cannabis plant, wait to make any drastic decisions! Yet if you’re fairly certain, consider some of these other common differences between male and female plants. Perhaps it will help you more confidently make a decision.
Other Common Differences Between Male and Female Cannabis Plants
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.
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.
My Cannabis Plant is Male! Now What?
I hope you started a few extra seeds, and have plenty of ladies left to grow! Once you determine that you have a male cannabis plant, get rid of it. Again, unless you want pollination and seeds, it is best to cull the males as early as possible. Simply separating the plants isn’t enough. Even if you relocate the male plant to another part of your yard, the pollen can carry in the wind. There are stories of female cannabis plants becoming pollinated from neighbors growing several blocks away.
However, the culled males don’t need to go to waste! One option is to chop up the male plant and use it to mulch other plants – much like we do with borage, fava bean greens, yarrow, and comfrey. You could also juice the leaves, which are full of nutrients. Heck, you could even steep the plant material in water to create a natural fertilizer as we do with stinging nettle. Finally, I’m sure your compost pile will welcome the male plant with open arms. Or would that be… with open worms?
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And that is how you determine the sex of cannabis plants.
In closing, I hope this article is interesting and useful in your homegrown adventures. Please feel free to ask questions in the comments below, and spread the cannabis sex love by sharing this article. Even if you like to grow mostly feminized seeds, don’t you find this stuff fascinating? I sure do. Thanks for tuning in and nerding out with me a bit. Best of luck this growing season!
Can You Tell the Sex of Cannabis Seeds from Their Appearance
Of all the things that can trip a grower up, sexing marijuana plants may just be the trickiest. Sexing plants is so important because growers are typically after the female plants, that produce the huge THC covered buds. Or the medicinal relief that CBD strains can bring. With such opposite effects of male and female plants, it’s easy to see just how important sexing plants is. But what if growers didn’t have to wait to sex their plants? While it would certainly make life easier, is sexing cannabis seeds possible?
Can you determine the sex of cannabis seeds?
This has been a question that has become a very hot topic online these days. After a quick search, growers can find multiple charts and explanations on how to sex cannabis seeds.
Unfortunately, there’s not much truth to any of these interpretations. It’s simply impossible to tell just by looking at them what the sex of any cannabis seed is. If it was that easy, feminized marijuana seeds would not be as popular as they are. People could simply buy regular seeds and look at them themselves.
Typically, marijuana plants cannot be sexed until they have already begun to grow. Cannabis seeds will look somewhat identical and plants in the vegetative stage will also look identical,. As the plants move into their flowering stage, they will start to show very clear signs as to what sex they are. While it would be much more convenient for growers to be able to determine sex before this point. The sad truth is that it’s just not possible.
So where do all the myths from sexing cannabis seeds come from?
Common myths on identifying the sex of a cannabis seed
One of the biggest myths of sexing cannabis seeds comes from a popular chart online.
The chart states that one can determine the sex of a cannabis seed by just looking at them. Within the chart, five cannabis seeds are shown. Three of these are female and two are male, supposedly. This chart says to look for a crater at the bottom of the seed. It explains that females will have a depression that is perfectly round. While males will have a crater that is misshapen and not uniform. However, this is simply not true. The craters found in cannabis seeds have nothing to do with the sex of a seed.
This same chart states that females will also roll easily across a table or surface, while males will not. While it does say that a magnifying glass and pair of tweezers is needed to examine the seeds. neither of these tools will make it any easier to determine the sex of cannabis seeds.
While growers may not be able to determine the sex of a seed, does the environment have anything to do with it? This is something else that has been hotly contested online.
Environment determines sex debate
We know that determining the sex of cannabis seeds cannot be done. However, it’s unclear as to whether environmental factors have any place in determining the sex of marijuana plants.
Research is carried out all the time to determine if a plant’s environment has anything to do with the sex it will turn out to be. And while there’s research stating that it does not, there’s just as much research stating that certain species do have their sex determined by the environment. This same research also states that using certain chemical treatments can also reverse the sex of a plant.
While environmental factors may not necessarily determine the sex of marijuana plants or cannabis seeds, it is known that certain environments can change the sex of a plant.
This will mostly happen when a plant is stressed by its environment. When this happens, the plant may think it’s going to die and as a result, will change itself into a hermaphrodite plant. By doing so, it will be able to self-pollinate itself and survive.
Growers know that hermaphrodite plants can be just as harmful to crops as male plants. Therefore, it’s very important that every grower understand how to sex marijuana plants. Particularly if they’re not using feminized marijuana seeds that will give them only females.
While it would be much easier for growers to be able to sex their cannabis seeds, the simple fact is that there’s no way to do it. However, sexing plants early on during their growth period is not only essential, it’s completely possible. Growers can even do it before their plants enter the flowering stage if needed. Then male plants can be removed and growers can enjoy a nice, full crop.
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