It is critical that you know how to identify which of your plants are male vs female. This guide will explain cannabis gender & reproduction. Male vs Female Cannabis Cannabis is a dioecious plant, which means it has male and female flowers on separate plants. When the male plant enters the reproductive stage, it will develop male pollen sacs. The female plant will produce flowers ready to accept the pollen. This also means that cannabis is not true to seed, Save up to 8 weeks and reduce operational costs by up to 20% with the LeafWorks Cannabis & Hemp DNA Sex Test. Identify male cannabis & hemp plants as early as 7 days post germination. The LeafWorks Cannabis & Hemp DNA Sex Test is 99% accurate.
Sexing marijuana plants & reproduction
Understanding marijuana gender and reproduction is essential to achieving the best possible harvest. However, it can be confusing.
For marijuana growing success you need to know what feminized seeds are and how to identify your plant’s gender.
This guide will explain these cannabis reproduction topics, as well as other important fundamentals such as what are hermies, and why so many people love sinsemilla.
We’ll also share some ideas on how to make a male plant female.
Cannabis gender identification & reproduction guide
Cannabis plant reproduction
First, let’s talk gender. Unlike most flowering plants, cannabis plants are dioecious, meaning there is a separate male and female plant, similar to humans.
Every plant possesses two pairs of sex chromosomes, X-chromosomes and Y-chromosomes.
Male plants have XY chromosomes, while female plants have XX chromosomes. Also, like humans, there is a natural 50/50 split between males and females.
There is a significant difference between the gender of marijuana and humans, however.
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This is because a marijuana plant can also be hermaphroditic. This means a single plant can have both male and female genitalia (a pistil and stamen).
Unlike humans, a cannabis plant’s gender depends not just on its genetics but also on environmental factors.
That is one reason why, when growing marijuana, you should be familiar with the different traits of female versus male plants.
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Each gender has unique qualities that may or may not be desirable in your garden.
Identifying males and females
It is critical that you know how to identify your male and female plants. However, it can be a bit tricky because cannabis plants do not start with gender.
Plus, they won’t truly reveal their gender until they start receiving 12 hours of darkness every 24 hours. In some cases, that is too long to wait.
Why do you need to know?
The simple reason is this:
Females produce THC and males distract them from it. Therefore, you want to determine the sex as soon as possible so that the males do not fertilize the females.
To explain it further:
Females without seeds (sinsemilla) have higher levels of THC, whereas males produce significantly less THC.
Preventing pollination, therefore, is the best way to ensure the highest quality buds.
Knowing what to look for
In terms of identifying between the two, in general, males have flowers, while females have pistils. Males tend to be taller as well.
All marijuana plants have flowers at some point. However, if you can’t differentiate between males and females on height alone, then flowers and pistils are good indicators.
This may seem simple, but to be honest, identifying the sex of a cannabis plant can be hard.
This is because marijuana plants don’t disclose their gender until they are mature enough to do so.
In fact, you may not know until your plants are almost ready to begin pollination.
If you wait this long to identify the sex of your marijuana plants, then it’s probably too late to grow sinsemilla buds.
Female cannabis plant
Female plants are often very recognizable. While both males and females will form flowers, the flowers from female plants usually do not bloom until after the males.
The females’ flowers will look like sacs that grow two stigmas (they sort of look like feathers) out of them.
Here are two features of females:
- They eventually open to form little yellow, cream or white flowers
- They have hairy, whitish pistils that trap pollen from males
You’ll find the stigmas in a node region of the main stalk. This is where a branch grows from the main stem, or where a branch grows from another branch.
Male cannabis plant
The easiest way to identify a male is by its rapid maturity. Males mature faster than females, meaning they will grow quicker and become taller about two weeks before a female plant. This is so they can drop pollen on female plants. Their flowering phase can begin as much as a month before females, giving growers some time to identify them.
Despite what you may have been told, male cannabis plants are not completely useless.
Obviously if you are growing a crop to smoke or sell, then you want females.
If you’re growing for the purpose of making hemp, the male plants make for a softer fiber, which is great for making clothing. Male plants also produce far more seeds, which you need to grow more plants.
Here are some typical features of males:
- They tend to grow straighter and don’t develop as many flowers as females.
- The flowers are generally located at the top of the plant.
- Unlike the female flower, male flowers are tight green clusters.
The male flower has a central part that looks like petal-shaped objects, five of which are inside of the sex organs.
To the untrained eye, they look like a tiny banana bunch. Male flowers are sometimes called “false buds” since they are actually pollen sacs.
These clusters begin opening over time until a stamen appears – ready to pollinate the females.
It is challenging to identify the sex of a cannabis plant-based on flowers. This is because there is a very short window between when they appear and when the plant is fertilized.
Instead, expert growers do this to identify sex:
They focus on finding the preflowers. These develop at the tips of branches and on the main stem. Preflowers are the immature first flowers that proceed the mature flowers.
Basically, it works like this:
If you notice a raised calyx on a small stem or stalk, then it is most likely a male. If this calyx isn’t raised, then it is probably a female plant.
Yes, it’s that simple. It can be hard to see the difference at first, but over time, every grower gets better at it.
Other methods for identifying the sex of your plants
Sometimes, you want other options. Maybe you need to know sooner, or perhaps you just prefer to use a variety of methods. Here are a few other ways to identify the sex of your plants.
Look at the growth patterns.
During vegetative growth, every plant, regardless of sex, starts to flourish. As the plants age, however, you will notice subtle differences in their sizes.
Some marijuana growers have even noticed certain signs early on that can help determine the sex.
Females tend to have more complex branching when they progress from the seedling stage to the vegetative stage. Males, on the other hand, tend to be slightly taller and less filled out.
This method is not foolproof, and you shouldn’t use it as a reason to throw out a plant.
Of course, the last thing you want to do is pull plants out at this early stage.
There is a reason to try it, however. It can help you get an idea, so you know which plants to watch later on.
(Note: this works best on outdoor grown plants, as those grown indoors under artificial light don’t usually exhibit these tendencies).
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Identify where the plant sprouted during germination.
Need to know as soon as possible? Some marijuana growers have discovered a method that identifies the sex of the plants just after germination.
According to their theory, if the sprout comes out of the top or bottom of the seed, it is generally a female. Side sprouts, on the other hand, generally turn out to be male.
While this hasn’t been scientifically studied, growers who have used this method report a 90% success rate.
Even with this anecdotal evidence, you shouldn’t use this as absolute fact. Let the plants grow a little and try to notice any distinctly male or female signs.
Don’t just throw away the marijuana seeds simply because they sprouted out of the sides.
Instead, keep track of your predictions so that you can make an informed decision later.
Clone your marijuana plants.
This is really the only foolproof way to determine the sex before the plants achieve maturity.
The best part about this technique is that it is easy. You merely take a cutting from one of your plants.
Cloning in 3 steps:
- Cut a small piece of the mother plant
- Place the cutting into potting soil and let it grow
- Force flowering with 12hr darkness/12hrs light after a few days
To identify the sex of your clones, you’ll need to keep them separate from the host plants.
This method works because, since they have the exact same DNA as their host, they will have the same sex.
Once the clones go into the flowering stage, it will be easy to determine their sex and the sex of their hosts.
Make sure you keep track of which clone came from which host, so you don’t get things mixed up.
You can also force the flowering of a regular plant (not a clone) and put it back into the veg stage once you know it is female.
However, this process can cause more trouble than it is worth. While effective at speeding up the reveal process, it can also place unnecessary stress on a developing plant.
Flowering and reproduction
Once your plants have developed their sex, they are ready for reproduction.
Here’s some detail on what happens during that process.
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Female flower formation
On a female marijuana plant, a large cluster of buds appears. This cluster is called the cola, and it consists of many sub-units of buds.
Within the cola, there are many pistils, which moderate the female processes of reproduction. Each pistil contains the stigmas that interact with male pollen.
Throughout the flowering process, cola is preparing for reproduction. The plant stretches and develops its bud sites.
These sites house groups of female marijuana flowers seeking to be fertilized. New flowers form on the top side of these subunits, and small stigmas emerge from the pistils.
These thin structures are often recognizable by their white hair.
They can still be pollinated even if they are not white.
Stigmas can sometimes die – especially after heavy rains or wind. This will cause them to become dry and change in color from brown to red.
This does not mean that pollination cannot happen. Even if a stigma is this color (instead of white), it can still receive pollen.
The female flower also has other hairs – glandular trichomes. These “hairs” are responsible for producing resin on the flowers and nearby leaves.
Up close the resin looks like a ball attached to a tiny neck. Its shape is a good indicator of how delicate they are.
If you handle the buds roughly, some of these trichomes can break off.
Underneath the pistol, you will find a smaller leaf called the stipule. It is more noticeable before flowers are formed.
Once the plant is fully grown you will need to start thinking about harvest time.
Our free little Harvest Guide will help you determine the best moment to cut your plants. Download it here.
When a male marijuana plant matures, it releases pollen and seeks out the female stigmas.
The pollen then travels to the egg cell located inside of the pistil, producing a seed. If this process does not happen, the female flower begins to change.
The fact is, Cannabis plants are designed to pollinate.
The pollen from a male plant can survive for a few days as it attempts to reach a female, increasing the cannabis plant’s chance of survival.
Pollen can survive on fabrics, and in air ducts. It can also be stored for intentional fertilization.
Female plants also do their best to be fertilized. Pistils grow larger when they are not fertilized. This is so they have an easier chance of locating pollen.
However, this effect does not last forever. When the pistils are completely mature, the stigmas will die, and they cannot be fertilized.
At this point, resin production will slow down or stop, and the trichomes will begin to break down.
The last opportunity for fertilization marks the beginning of the plant’s death, but it is not immediate death.
Pistil maturation occurs gradually, instead of all at one time, leaving growers plenty of time to harvest.
What about autoflowering seeds and plants?
Most standard marijuana plants start to flower at the end of summer as days start to get shorter and the amount of light drops.
Regular plants recognize that they need to start maturing before the onset of winter, but autoflowering plants are different.
They will enter the flowering stage even if they receive a full 24 hours of light.
An automated flowering period is great for growing in places with unusual growing seasons, or when you’d like to harvest twice in a single growing season.
This is because a decrease in daylight hours (typically triggered by the change in seasons) is not needed for these plants to flower.
Feminized autoflowering seeds provide the dual benefits of a quick harvest and not needing to identify plant sexes.
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Autoflowering marijuana seeds also produce plants that are generally small and ideal for outdoor growth. With these, you can plant a couple for every square foot.
Plus, they only take about 10 weeks to harvest. That being said, the yield and quality are not up to par with seeds that flower regularly.
The features of autoflowering plants
- Generally, 12 to 23 inches tall (30 to 60 centimeters)
- Suitable for outdoor growth
- Starts flowering automatically after around 3 weeks
- Yield between 0.5 to 2 ounces depending on hours of sun
- Goes from seed to harvest in about 9 to 10 weeks
Autoflowering seeds will yield between 50 and 500 grams per m2, but this depends on how well you care for your plants.
Prevent fertilization with feminized seeds
Many growers prefer cannabis that is not pollinated and does not have seeds. It is called sinsemilla, which is Spanish for without seed.
Because these plants did not produce seeds, their plants tend to have more trichome production and more potency.
Feminized seeds help prevent fertilization by ensuring your seeds grow into female plants. If there are no male plants nearby, your female plant will not form seeds.
Many growers try to prevent pollination. Here’s why you should consider growing sensimilla using feminized seeds.
Save the energy for the buds
Pollination means that the plants will use their precious energy for creating seeds instead of flowers. This has evolved due to natural selection.
Since a plant that produces more seeds is more likely to reproduce many future plants, the trait is passed on.
Although this is an advantageous feature for marijuana’s survival, it is not exactly what smokers are looking for in a weed plant.
When female plants grow into maturity without being fertilized with male pollen, they can usually produce a more resinous bud. This is because there are no seeds to take over the valuable flowering area.
Sinsemilla is difficult to grow
Sinsemilla weed is expensive not just because it is high quality. It’s also because preventing pollination is hard.
Your female plants could be pollinated by male plants from up to a mile away!
You could also simply identify the sex incorrectly or wait until it’s too late to separate the males from the rest of the marijuana crop.
If you make a mistake, don’t freak out.
While seeds aren’t always wanted, accidental pollination frequently occurs. If you are worried that it has happened to you, look for swollen calyx rings (beneath the stigmas).
If unintentional pollination occurs, remember that a few seeds won’t ruin a harvest.
After all, it may only be one flower, and your plant has hundreds of them. You can either pick those seeds off or leave it alone.
A few seeds aren’t bad
Although you probably don’t want them, producing a few seeds isn’t necessarily a bad thing.
If one crop is particularly delicious or potent, you want those plants to produce a few seeds.
Store these seeds correctly and label them accurately so that you can identify which seeds produced the best crop later. Then, use the seeds that produced the desired traits in a future growing season.
Now that we understand the flowering stages’ role in marijuana reproduction let’s go more in-depth into the different sexes.
The female marijuana plant
Female marijuana plants take a tad bit longer than males to reach sexual maturity. But once they do, it is quite easy to spot them.
During the pre-flowering stage, the female plant will grow one or two wispy white hairs where buds will form. It means that the plant is ready to bud anytime soon.
The hairs will be visible on the main stem that connects to the nodes or branches. Once the hairs are spotted, that is a great sign that the plant is a female.
Ensuring female plants
Female plants tend to start showing hairs even before the flowering stage, or changes in grow light schedules, but they can still be fertilized by a single male. Most growers dream of having an all-female garden. This way they won’t have to deal with removing half their plants when they reveal themselves as male. This is where feminized seeds come into play.
Feminized seeds help improve your chances of growing female plants.
Feminized marijuana seeds are seeds that only produce female marijuana plants.
But they aren’t the only thing that makes a cannabis plant female. Under some conditions, female (and feminized) seeds can become hermaphrodite plants and fertilize themselves.
How feminized seeds are created
Are you wondering how breeders create a female seed? Here’s a summary.
Early feminized marijuana seeds usually were made with two female marijuana plants.
One of the plants would have already shown hermaphrodite tendencies, i.e., prone to produce male marijuana flowers when it was stressed.
The intersexual-prone marijuana plant is then stressed by light cycle interruption or pruning. The stress would encourage them to produce male marijuana flowers.
Then, the pollen from the hermaphrodite plant is applied to the ‘true’ female (i.e., a plant that did not easily display intersexuality when stressed).
The downside of this method is that the female marijuana ‘pollen donors’ already had quite a strong tendency to turn intersexual.
That tendency, in turn, was very likely to be inherited by the resulting feminized seeds.
In the early days of feminized marijuana seeds, hermaphrodites were a reasonable concern, but nowadays hermaphrodites formed from feminized seeds alone are rare.
Today, breeders use a technique called rhodelization. It uses different forms of silver to force female plants to produce male flowers.
This new, more intensive, technique produces stable and consistent seeds. Now, female plants with a very minor tendency to turn intersexual can be used, instead of the hermaphrodite plants needed in the past.
Best of all, none of the genes are modified, so the seeds produced are female.
These female plants stay female even when placed under harsh, irregular, or stressful conditions.
This means that their offspring have no more tendency that a normal female marijuana plant to turn intersexual.
If anything, the parent marijuana plants are physically modified by silver, and the seeds are produced naturally, through pollination.
Sexing Cannabis Seeds
Sexing cannabis seeds is vital for success. Whether a sensimilla grower or seed breeder it is important to know the boys from the girls.
Male vs Female Cannabis
Cannabis is a dioecious plant, which means it has male and female flowers on separate plants. When the male plant enters the reproductive stage, it will develop male pollen sacs. The female plant will produce flowers ready to accept the pollen. This also means that cannabis is not true to seed, i.e. seeds from a cross pollination will not directly represent the flowers they originated from and instead contain genetic material from both the mother and father plant. Because cannabis has both male and female sexes, you need to identify and understand the differences. Cannabis gender cannot be identified by seed or growth patterns and the only reliable method is to observe the reproductive organs that develop.
Growing for weed or seed
When you begin your growing journey, you will need to decide what your goal is. If you want to grow flowers for consumption or processing, you will want to ensure you only grow female plants that do not get pollinated. Seedless cannabis flowers are referred to as sensimilla and are more potent and flavourful than seeded cannabis flower. This is because when the female plant is pollinated, it stops directing energy to producing oils and cannabinoids. Instead, the pollinated plant focuses all its’ energy on producing seeds. Seeded cannabis is undesirable for medicinal and recreational growers yet it is first prize for many hemp and food crop growers, as well as breeders.
If you want to create seeds, you need to grow both female and male plants. You can separate your male plant as it starts to produce pollen. Then collect the pollen and pollinate only one or two branches on your female plant. By doing this you can enjoy the fruits of your labour and produce seeds for the next season. The other option is to simply let a male or two pollinate all the plants over the growing season. Leading to a harvest of hundreds to millions of seeds.
Sexing Cannabis Seeds
The best way to identify your plants gender is to wait until it is sexually mature and inspect the nodes or growth points. Plants show sexual maturity by displaying alternate branching and “pre-flowers”. These traits begin in the early flowering stages or late vegetative stages. Pre-flowers are reproductive organs that begin developing before the plant fully enters the reproductive stage and can be used as early identifiers. Male plants produce pollen sacs which look like round balls hanging off the plant.
Female plants produce bracts and white hair like pistils. Pollen sacs are rounder in structure where bracts appear more angular with a thin white pistil growing from within. It is wise to wait until you are entirely sure of your plants’ sex before deciding what to do with it. Not all plants produce the same looking organs and early identification can be tricky for some cultivars. Paying careful attention at all stages of growth will ensure that you are able to far better control the quality and results of your grow.
Cannabis sex isn’t that simple
As if cannabis isn’t woke enough, it can also occasionally be gender fluid. In cases of poor genetics, stressful environment or purposeful reversal, the cannabis plant can display both sexes at once. This is called an intersex trait or “hermie”. Hermies are traditionally undesirable as they may seed crops that are intended to be seedless. Thereby greatly reducing the value of the crop.
However, in recent times breeders have perfected the art of using these traits to their advantage. Femisied cannabis seeds are created by forcefully introducing intersex traits in a female plant. Then using its pollen to pollinate other stable clones of the same female plants. This means that the seeds made from the cross will be identical to the mother plant and almost always female. These are known as feminized seeds. Nowadays most breeders will use chemicals to induce this change in the plant, however almost any stress of the right intensity can induce intersex traits across the spectrum.
It’s easier than ever
Always ask first. If you are unsure about sexing cannabis seeds, there are many online resources you can draw from. Facebook groups make a great place to share and learn from others. Similarly online forums are an excellent resource to browse and interact with other growers without compromising your anonymity. But be warned, there are as many unhelpful opinions as there are helpful. As not all comments are from experienced growers. Try and find a community of people whom you feel comfortable with and have a healthy track record.
You should always source your genetics from reliable and trustworthy providers. There are few things more frustrating than finding an unwanted hermie a few weeks from harvest. In South Africa it is now very easy to access high end and reliable genetics. Whether you want to start from seed or clone, there are multiple vendors supplying feminised seeds and clones. For the aspiring breeders, some vendors even supply regular seeds and male pollen that you can apply at your convenience.
Get the right grow gear
There’s an old proverb about not building your house on the sand and how you should plan for success. Growing A+ cannabis requires a dedication and flexible budget for the happiest results. Don’t be afraid to invest a little bit in the correct grow medium and nutrients, it will make all the difference.
We hope that we have taken some of the mystery out of sexing cannabis seeds. Honestly though, it will be surprisingly easy to get the hang of sexing cannabis seeds in no time at all. You will spot the signs and differences quickly with a well-trained eye and should be well on your way to beautiful big buds. If you still need a little help spotting the boys from the girls? Please contact our grow pros for some top shelf advice.
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