In this guide you will learn
- Cannabis plant reproduction
- Identifying males and females
- Knowing what to look for
- Other methods for identifying the sex of your plants
- Flowering and reproduction
- What about autoflowering seeds and plants?
- Is it best to prevent flowering?
- The female marijuana plant
- The male marijuana plant
- Hermaphrodite marijuana plants
- Cut your losses and keep growing
Understanding marijuana gender and reproduction is essential to achieving the best possible harvest. However, it can be confusing. This guide will explain cannabis reproduction so that you are prepared. I’ll also discuss hermies, reveal the reasons why so many people love sinsemilla and share some ideas of what to do with a male plant.
Tip: make sure to download my free Grow Bible for more information
Cannabis plant reproduction
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.
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 their genetics but also environmental factors. That is one reason why, when growing marijuana, you should be familiar with the different traits of female versus male plants. 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 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.
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.
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 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).
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 flowering of a regular plant (not a clone) and put it back into 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.
Female flower formation
On a female marijuana plant, a large cluster of buds appear. 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, a 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.
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.
Is it best to prevent flowering?
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.
It’s no wonder that many growers try to prevent pollination.
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
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.
The feminized strains sold by I Love Growing Marijuana are genetically female and produced using this silver method. That’s why we are proud to guarantee that the feminized marijuana seeds sold in our webshop are as stable as regular marijuana seeds.
For more on feminizing marijuana seeds with colloidal silver read this article.
The male marijuana plant
Male marijuana plants do not produce buds, but they will have flowers. These mainly contain pollen. These plants are often thought of as useless or annoying, but they can be more useful than you might think.
During the pre-flowering stage, male plants start showing grape-like balls along its stalks. These clusters, called pollen sacs, contain powdery pollens. Typically, after a week or two into the flowering stage, the cannabis plant reaches maturity. As a result, the pollen sacs will burst open and spread pollens everywhere.
While male marijuana plants are hard to distinguish from females during growth, it is still a good idea to be vigilant and watch out for them. Just remember to watch out for small grape-like balls as early as the when they are seedlings.
How to use male plants
One of the most exciting times for a grower is when your plants reveal their gender. However, if you’ve discovered that there is a male among your female plants you may wonder what to do with it. You may even be tempted just to toss it.
After all, what’s the point; male cannabis plants don’t produce those delicious smokeable buds that you’re hoping for. Don’t toss out that plant just yet. There are still a lot of uses for male cannabis plants.
Make hemp fiber
Both genders can be used to make hemp fiber. However, the hemp fiber made from male cannabis plants is a lot softer and better suited for making clothing, blankets, and tablecloths.
Female cannabis plants are better known for the coarser hemp fiber used to make rope and other similar things. As we all know there are many uses for hemp. That should be reason enough right there to keep your male plants around.
Use them for Breeding
Male cannabis plants are a must for breeding. Naturally, when you first start out, you’ll be more comfortable with clones. There’s nothing wrong with that. You can always just clone your mother plant and expect to get consistently good results.
However, I can promise you that cloning will get boring after a while. Part of the fun of growing is the unexpected, and that is breeding. Males make good fathers, as long as they have good genes to pass on down to their offspring.
One of the best uses for male cannabis plants is the production of seeds. When you’re trying to grow smokeable buds, producing seeds might seem like an unwanted hassle. This is not the case. You need those seeds to keep breeding.
Make Some Hash
Contrary to popular belief, male cannabis plants do have psychoactive properties. They contain THC, but they’re not anywhere close to as potent as the female. That’s why you don’t try to smoke them (well, that and they don’t have buds).
However, you can use them for hash and other concentrates. All those trimmings, leaves, stems, etc., still have THC in them, and that shouldn’t go to waste.
Protect your Garden
You can also use male cannabis plants as protectants for your garden, whether for your cannabis crops, or your regular vegetable garden. (You know, the plants that you don’t mind showing off when you have company over.) Male plants still contain terpenes, which are excellent for pest control and disease prevention. You can even use them to make terpene oils, a pretty dank pest control.
Regular seeds and male plants
Regular marijuana seeds come from one male and one female parent and can produce either male or female plants. It is virtually impossible to tell if a regular seed will turn out to be a male or a female later on.
Of course, after you reach the flowering stage, it is much simpler to identify males and females. Males will produce oval pods while females will produce a calyx shaped like a teardrop.
The ratio for male-to-female growth with regular seeds is around 1-to-1 (approximately 66% female). When you start growing, it’s in your best interest to just assume that 50% of the seeds will end up female. You should germinate a few extra seeds to make up for all the males that you’ll discard later on during the early flowering period.
Should you choose regular seeds?
Many different variables determine whether regular seeds are your better choice. They include:
- The conditions of the grow
- The amount of time and space available
- The grower’s preference
- The grower’s experience
There is one situation where you’d always need regular seeds. That is if you’d like to breed cannabis and produce new seeds. For that, you’d need both male and female plants, which would require regular seeds. If you have no interest in breeding and you just want to have some outstanding bud, then feminized seeds might be a better choice.
Hermaphrodite marijuana plants
Cannabis plants will do everything possible to reproduce. Sometimes that means pollination by hermaphrodites. Yes, cannabis plants can change their sex so that they can reproduce. This intersexual ability is an evolutionary trait that protects the cannabis species.
So, what is a hermaphrodite?
A hermaphrodite is a plant that exhibits both male and female reproductive capacities. Marijuana plants can easily become hermaphrodites in response to stress in their environment. They do this because the plant detected that growing conditions are not favorable, which means it is less likely to reproduce.
Poor conditions mean that a marijuana plant is less likely to survive the complete season. They also change in response to there not being a plant of the opposite sex to pollinate them.
Although annoying to marijuana growers, hermaphrodites (often called ‘hermies’) are an excellent survival mechanism for the cannabis species. It is part of their genome, meaning every marijuana plant has the potential to ‘hermie. However, some plants are more likely to do so than others.
Why a marijuana plant hermies
Of the many misconceptions about marijuana, the misunderstanding about hermaphrodites is probably the largest. As a flowering plant, marijuana is not firmly one sex or the other. It’s unusual because it’s dioecious (producing separate male and female flowers on different plants).
However, growers must remember that every marijuana plant can produce flowers of the opposite sex under certain conditions and it can happen at any time. These conditions could include:
- Problems in the light/dark schedule
- Lighting that is too bright
- Temperatures that are too hot
- Nutrient deficiencies
- pH problems
- Lack of water
- Poor genetics
- Feminized seeds using rhodelization
Although rhodelization is less likely to cause hermaphrodites than previous feminization methods, there is still an increased risk of intersexuality. This is why it is not a good idea to clone feminized seeds. The stress of cloning (combined with its genetics) will likely cause it to become hermaphrodite as well. For breeding purposes, it is best to choose a mother plant that shows no signs of hermaphroditism even when under stress.
Types of hermaphrodites
There are two forms of hermaphrodites and plants can have varying levels of hermaphroditism. However, the term is used to refer to any plant that is not distinctly male or female.
A true hermaphrodite has both male and female features growing but on different parts of the plant. This tends to be due to genetics. In other words, the plant gained the ability at birth due to being born from a hermaphrodite parent.
True hermaphrodites don’t always become hermies even though they have the genetics for it. With expert growing they can grow into females, however, under even the slightest stress they may transform into their natural state – a self-pollinating hermie. If cloned, these plants will always become hermaphrodites. Hermaphrodites are not as potent as female plants, even if they flower.
Most of the time, a true hermaphrodite plant will look like a male plant. As such, it will form grape-like balls that contain pollens.
Another type of hermie is a female plant that forms small growths during the flowering stage. Because these growths look like bananas, these types of hermies are often called ‘bananas.’ Until this time, these plants appeared female, but after a while (usually due to stress) they become hermaphrodite.
While surprising, the process of female marijuana plants becoming male is not that rare. In fact, it frequently happens with a female plant that goes too long without being pollinated or harvested. As a last-ditch effort to continue the species, she becomes hermie and produces seeds herself.
Hermaphrodites can be male to female as well, with male marijuana plants growing pistil flowers, but this is less common.
Levels of hermaphroditism
Because a hermaphrodite can have any number of opposite-sex flowers, there are varying levels of hermaphroditism. Here’s how to categorize what you have:
Mostly Female Flowers: The plant can still function as a female by removing male flowers
Equal Number of Males and Females: The plant will most likely self-pollinate.
Mostly Male Flowers: The plant will function as a male.
It is crucial to figure out what kind of hermie you have to know what to do with it.
Banana hermies have pollen sacs that are not round like true hermies. This is because they are not pollen sacs. They are actually elongated stamen inside of a pollen sac, that looks like bananas.
Want to know the crazy part?
They are also yellow and grow in bunches like miniature bananas. However, they are sometimes lime green.
The most significant difference between bananas and other hermies is that the “banana” pollen sacs do not need to open to pollinate. Because they are the exposed male part of the pollen sac, they start pollinating as soon as they appear.
This means, if you see them it may already be too late.
Dealing with hermies
Hermaphrodites are challenging for marijuana gardens because they make it possible for female plants to pollinate themselves or any neighboring female plants. They’re also easy to miss if you do not regularly inspect your garden.
Removing hermaphrodite plants
Self-pollinating hermaphrodites generally lead to more females and more hermaphrodites. Therefore, when you spot a ‘hermie’ in your all-female garden, you may want to practice culling. Culling is the process of removing plants with undesirable characteristics so that your overall product does not exhibit these same traits.
In other words, throw away your hermies.
Especially with bananas, it is best to immediately remove the entire plant before it has a chance to produce more. Then, watch for bananas on other plants. Bananas grow quick and do their damage even quicker. If you start to see a bunch of them, harvest whichever plants haven’t been fertilized and consider yourself lucky.
Some growers have been able to salvage hermaphrodites since they can sometimes still produce decent amounts of THC. Others have tried to hack this system by creating hermaphrodites out of male plants (with little to no success).
Again, the best thing to do with hermaphrodites is to remove them.
If you don’t want to remove the plant altogether, you can simply pluck off the male flower bunches that appear. This will restrain the hermaphrodite effects and keep it from pollinating itself or other nearby plants. It also limits its ability to continue its own line of traits.
This option works best on true hermaphrodites, where you remove the pollen sacs before they burst. You’ll also need to identify every hermie and remove all the sacs in time. However, this can be challenging since the pollen sacs can reappear after they have been removed.
Keep in mind, a few bananas aren’t a big problem. If you only have a few, just remove them.
However, the problem is that it is rare for a plant to only have a “few bananas.”
Cut your losses and keep growing
In the end, you don’t need to go to heroic lengths to save your plants. Whether it’s because you have male plants or because they are hermaphrodites, sometimes the best choice is to cut your losses, remove the plants, and focus on the remaining female ones. After all, if you dedicate a lot of time to just a few plants, you can ensure that those plants end up with the highest possible yield.
Marijuana plant reproduction can be difficult to understand, especially when cannabis can self-pollinate under certain conditions. As a grower, you must stay vigilant. Know how to recognize the sex of your plants before they start to reproduce.
The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]