Hydroponic Marijuana Sexing Marijuana sexing simply means determining the gender of your marijuana. While cannabis occasionally may be hermaphroditic (having both pistils and stamens), generally, Learn how to tell the difference between male and female cannabis plants, so you can properly sex your cannabis in the early pre-flower stage. Sex Detection Screening Identify and Eliminate Male Plants, Days After Germination With DNA-based testing, it is possible to identify male cannabis plants weeks before they show any visual sex
Hydroponic Marijuana Sexing
Marijuana sexing simply means determining the gender of your marijuana. While cannabis occasionally may be hermaphroditic (having both pistils and stamens), generally, plants are wholly male or female. After four or five weeks you will start to have a chance at sexing the plants. Although generally considered one of the trickiest parts of growing your own marijuana. Marijuana sexing is quite straightforward and will become easier as you gain more experience. The reason for sexing your plants is so that you can remove male plants before they have a chance to pollinate the females. If this occurs the females will start to develop seeds and this will divert their energy from THC production. Which if course is not cool. Left to their own devices plants will develop pre-flowers after around 4 – 6 weeks. This is the right time to remove the males and commence the flowering stage. Marijuana is a dioecious plant which simply means that the males will produce pollen and the females will produce seeds. Although, as in other forms of life, hermaphrodites do occur. Unless you are a breeder or otherwise growing for seed stock, it is preferential to have all female plants as it is the unfertilized calyx or buds which are the most psychoactive and potent part of the plant, the THC, CBN and CBD. So your seedless buds (sinsemilla) are the most preferred harvest for smoking as no energy or weight has gone into making seeds. Therefore, to use energy, time and space on male plants is wasteful of limited resources; thus they should be identified as early as possible and either segregated (for breeding) or destroyed before they release their pollen. Occasionally marijuana will show pre-flowers (immature indicators of the sex of the plant) while still in the vegetative state, but generally require the shift to the flowering phase (shortening the light regimen to 12/12 – 12 hours of light and 12 hours of total dark).
Flowering is the only true way to sex your plants
Although you may get a clue from their growth patterns before flowering. Male cannabis plants tend to be leggier than female plants with a longer internodal length. Female plants are squatter with more leaves and a bushier aspect. Male pre-flowers should be clearly visible to the eye, although a magnifying glass will make your job easier. Male flowers form at the junctions of the branches and stem and the pollen sacs form little balls. Female pre-flowers will also form at the junction of branches and stem but will normally start to form at the fourth or fifth branches up from the base. They are easily distinguished by the appearance of pairs of tiny white hairs, known as pistils. Some growers force flowering by changing the light cycle before the appearance of pre-flowers. They then watch their plants closely for the appearance of flowers and remove the males. However, others believe that this can stress the plants and is not a proven way of speeding up the process as plants forced in this way may spend longer in the flowering phase, cancelling out the advantage.
A magnifying glass is helpful though not necessary. Look near the top branches right where they fork from the stalk. The male sex organ will look like a small playing card-type club. The female sex organ will display a calyx with two small white hairs protruding from the top. If you are unsure or unable to determining the sex, then simply wait a few more days until the organs are more mature and easier to identify. The males are still way too young to create pollen so there is no danger in waiting.
- Force flowering by putting the plant under 12/12 light cycle. The drawbacks of this are that two separate rooms or grow spaces are required. More importantly the plant gets hormonally confused being switched between vegging to flowering, then back to vegging and finally flowering once again. This method allows you to cull your males early, but most likely will delay your harvest for a few weeks.
- Cover a lower branch with black plastic cut from a garbage bag. Do not use a thin bag that allows light to pass through. This must be put on every 12 hours and removed every 12 hours at the same time. The branch will show its sex long before the rest of the plant while still allowing it to ‘veg’ otherwise normally.
Occasionally a plant will exhibit both sexes. This usually occurs when a female plant is late into flower and remains unpollenated. In a last ditch effort to create seeds, marijuana plants have an emergency back-up plan: they sometimes create a small number of male flowers in an attempt to pollinate themselves. Some growers pinch off the few visible ‘bananas’; others may remove and/or destroy the plant so as not to pollenate a whole crop. Marijuana sexing is not difficult once you familiarize yourself with some basic plant physiology.
Cloning marijuana is a great method to use as all shoots are genetically identical to the parent. Thus if you find a donor parent plant that you like (one with desirable genetic traits) and is large and healthy enough to remove branches for cuttings, you may skip the whole sexing ritual as they are 100% the same sex as the parent.
Feminized marijuana seeds
These are a relatively new phenomenon on the cannabis culture scene, and while looked down upon by some old-timers, purists and large-scale growers, are a great boon to the small grower with limited space and time. It is currently not possible to tell the sex of a cannabis seed by examining it (though many untested myths abound), but the mix of males and females is roughly half and half. The larger the amount of seed purchased and/or planted, the closer the ratio will be to 50%. However, if you purchase a small quantity such as five seeds, it is possible to get all males, all females or any mix in between. Feminized marijuana seeds are not foolproof nor 100% guaranteed, but ratios of 90%+ female are quite common.
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!
Sex Detection Screening
Identify and Eliminate Male Plants, Days After Germination
With DNA-based testing, it is possible to identify male cannabis plants weeks before they show any visual sex features. DNA is extracted from one of the plant’s leaflets, as early as the second set of true leaves. Males can then be removed from a grow in order to maintain female flowers rich in cannabinoids. This method is an improvement over traditional visual inspection because it allows growers to identify male plants earlier, more accurately, and with less labor.
Save Weeks Worth of Resources
It takes approximately 6 weeks for a cannabis plant to show signs of sex. By eliminating male cannabis or hemp plants early, cultivators can make better use of their resources, canopy space, and labor.