How to separate male and female weed seeds

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!

When to Separate Male and Female Cannabis Plants

Cannabis is an annual dioecious genus, meaning the species within the genus produce distinctly male and female plants each year from seed. In today’s cannabis industry, nearly all cannabis jobs and products focus on the female plant—and for extremely good reasons. It is important to learn when to separate male and female cannabis plants.

Female cannabis plants are the sex that produces the highest amount of coveted cannabinoids, which more often than not is tetrahydrocannabinol (THC). Females are undeniably the more exciting of the two sexes. Females produce the fragrant and potent flowers that all cannabis consumers know and love.

In comparison, the male cannabis plant isn’t nearly as enticing. Even the male plant structure is comparatively plain, even ugly.

When it comes to the battle of the sexes in the cannabis space, there’s no denying that females win, hands down. That fact aside, males are really just as important as females, although their usefulness is not as apparent. Without males, there would be no cannabis strains, and the industry would not exist.

Each of the two cannabis plant sexes plays a crucial role – meaning there’s a critical need to properly identify each sex, as well as when and how to keep them separate from each other in all but the rarest of circumstances.

First, A Little History on Male & Female Cannabis Plants

In past decades, cannabis—usually imported cannabis—was smuggled into the United States for the black market from countries such as Colombia, Mexica, Afghanistan, and Thailand. Bags of this type of bud were nearly always seeded in varying amounts, because male or hermaphrodite plants would be found within or in close proximity to grows consisting of females.

This abundance of seed wasn’t necessarily undesirable for the growers, because it ensured a ready supply of seed stock for future grows. The downside of this seeded marijuana was that it was low-quality, because female plants halt the production of resin in the form of frosty, sticky trichomes on their flowers once they become seeded by male pollen—and trichomes contain the highest levels of cannabinoids, including THC, the psychoactive property in cannabis.

Eventually, unseeded cannabis began to enter the black market, referred to as “sinsemilla,” which translates in Mexican Spanish to “without seed” (the word is derived from Latin sine “without” [see sans] + semen “seed” [see semen]). This unseeded cannabis quickly got the full attention of cannabis consumers because it was much higher quality from its high resin content.

Very quickly, sinsemilla was in high demand, and people began to shun heavily seeded flower, referring to it disparagingly as “shwag weed.” No one wanted the seeded stuff anymore.

In today’s cannabis industry, all commercial flower is sinsemilla, and it goes without saying that the flowers don’t contain seed. The term “sinsemilla,” although sometimes still heard, has become a somewhat antiquated colloquialism of the past.

How Modern Growers Keep Male & Female Cannabis Plants Separate

Today’s industry also cultivates cannabis under much more controlled environments that the marijuana fields found in other countries. Except for closely controlled and monitored breeding projects, female cannabis and male cannabis plants are segregated and kept apart from one another.

When a choice male plant (typically one with good structure and heavy resin production) is identified and its pollen collected, breeding it to a prime female is done with strict protocol in place.

For the home grower, the practice of culling male plants is extremely important to the overall success of the cultivation project. Today’s home growers typically acquire their seeds from a seed company or bank and have a choice between feminized seed (seed that will produce only female plants) and normal seed (seed that will produce both female and male plants).

Growing From Feminized Cannabis Seed

If growing only female plants is the ultimate goal, there’s much to be said for the merits of feminized seed. This type of seed comes from specialized breeding practices that only utilize female plants, so this seed lacks the male chromosomes to produce male plants. When the plants begin to reveal their sex, they will all be female.

How to Tell If A Cannabis Plant Is Male or Female

When it comes to growing cannabis, it truly is essential that you learn the difference between male and female cannabis plants. By learning this simple technique, you can easily decide what you want to pollinate and what you don’t.

Understanding Plant Reproductive Morphology

First, let’s take one step back to fully grasp why we need to separate cannabis plants by male and female in the first place. This is commonly referred to as the plant reproductive morphology, which is simply the study of the physical form and structure of a plant’s sexual reproduction parts.

While there are actually many complex forms of morphology, for the sake of keeping it simple, we’re only going to cover three of the most common ones.

Hermaphrodite (bisexual):

This is a type of plant that forms both male and female parts on the same plant. Therefore, this plant will be able to reproduce on its own. However, in cannabis plants, you can discover a “hermied” plant by banana looking shoots, which form on the flowers. While this can be the genetics of the cannabis strain, it may also be an indication of the plant getting too stressed out. When a plant gets too stressed and fears it will die, it may begin to form male reproductive parts. This is to ensure that seeds can drop for its survival (keep reading for more info on detecting “hermied” cannabis plants).

Monoecious:

For this type of plant, it will form both male and female reproductive parts. However, they will not be on the same flower as they are with hermaphrodite plants. Within monoecious plants, you will find one flower has female parts, while another has male parts. In cannabis, this is very uncommon to find. Actually, it’s only been reported a few times in history and something that we’ve never personally seen. If this were to happen, you would find one stalk with definitive male characteristics and other branches of the same plant with definitive female characteristics.

Dioecious:

Now, with a dioecious plant, you will find that the plant either produces all male parts or all female parts. This means that no single plant can reproduce on its own. The female actually needs its male counterpart to continue producing seed for the following year. And, you guessed it, this is the category cannabis falls into and why you must separate your males from females. If you fail to separate them all, you will likely find that the male plants pollinated your females. Therefore, leaving you with a handful of buds chalked full of seeds.

How to Tell the Difference Between Male and Female Cannabis Plants

Now, with an understanding of the various sexual organs within cannabis plants, let’s get to the fun part – separating your lady friends from their male counterparts.

After the seeds have sprouted and the plants have had a chance to grow, it will be time to find out which ones you’ll be keeping to flower out and which ones you will be chopping down to avoid seeded buds.

Usually, when starting from seed, you will need to wait about four to six weeks before the male and female parts will be formed well enough for you to see the difference.