Understanding hermaphroditism in cannabis is key to becoming a more capable and experienced grower. It's something most cannabis cultivators will encounter at some point, so it pays to be informed. Find out how to identify and deal with hermaphrodite cannabis plants, and how to prevent them from ruining your precious crop in the future!
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Cannabis plants are dioecious, meaning there are separate male and female plants. Whereas many plants can pollinate themselves, dioecious plants require a member of the opposite sex for reproduction.
However, the cannabis plant has a fascinating adaptation that allows females who suspect a lack of male pollen to develop male sex organs and pollinate themselves. Known as hermaphroditism, this trait is key to the species’ survival in the wild, but it doesn’t bode well for good harvests! So read on to discover why hermaphrodite cannabis plants appear, and what to do if you find them in your grow room or garden.
What Is Hermaphrodite Cannabis?
Hermaphrodite cannabis plants are those that exhibit both male and female sex organs. It is a natural adaptation designed to facilitate self-pollination, in case of environmental stress or little breeding potential. Some strains are genetically predisposed to it, but in other cases it is purely a behavioural response to the plant’s environment. With this in mind, there are two distinct types of hermaphrodite plants to consider.
True Hermaphrodite Cannabis Plants
True hermaphrodite plants are those that are genetically predisposed to it, such as Thai sativas. These plants develop full, distinct male and female sex organs. At some nodes, flowers with stigmata (pistils) will grow, whereas pollen sacs with stamen will protrude from others.
Bisexual Flowers
Bisexual flowers occur when a plant senses dire environmental stress during the flowering stage. When they suspect they will not be pollinated from elsewhere, they develop exposed stamen (commonly known as "bananas") directly on the flower in order to pollinate themselves.
What Causes Hermies?
As mentioned, there are genetic and environmental causes for hermaphroditism in cannabis. For those that are genetically predisposed, it is as simple as that. Some strains simply have a greater chance of becoming true hermaphrodites. It is unclear whether you can do anything to influence it in a particular marijuana plant.
Though, for most strains, avoiding bisexual flowers means keeping your plants as happy as possible. The more stressed they are exposed to, the more likely they are to turn hermie.
Some of the major stressors are:
- Disruption in flowering stage photoperiod (e.g. light leaks)
- Too hot or cold
- Too little water
- Infestation
- Physical stress, such as training during the flowering period
- Incorrect fertilisation
- pH imbalance
What do all of these have in common? Each makes the likelihood of plants surviving much less, and therefore the plants respond by trying to fertilise themselves in order to continue their line. It’s genius. But it can be annoying as a grower.
Another factor that can trigger hermaphroditism is waiting too long to harvest. If the flowers go too long without being pollinated, this tells them there are likely no male plants nearby, and that if they want to produce seeds, they’ll need to pollinate themselves. So harvesting on time is crucial to avoiding hermies, and to achieving top-quality bud.
Are Feminized Seeds More Sensitive To Hermaphroditism?
If you buy feminized cannabis seeds from a good breeder, they should be no more likely to become hermaphroditic than regular seeds.
However, if sourcing from an unreliable breeder, the risk of hermaphrodite plants is higher, as one way of breeding feminized cannabis seeds is to force plants to become hermaphrodites—and seeds from a hermaphroditic plant have a greater chance of becoming so themselves.
One thing to bear in mind, though. Even in cases where feminized seeds are more likely to produce hermies compared to regular seeds, you’re still likely to end up with more female plants using the former type than the latter; with regular seeds, about 50% turn out to be male plants.
How and When To Identify Hermaphrodite Cannabis Plants
Accurately identifying a hermaphrodite cannabis plant on time will prevent it from affecting the rest of your grow. So learning the difference between males, females, and hermies is key to successful cultivation.
Whichever they turn out to be, it is impossible to tell (without DNA sequencing) the sex of your plant before the pre-flowering stage. So when you switch your lights to 12/12, be prepared to get eagle eyed on those nodes!
How To Determine if Your Cannabis Plant Is Female
Female cannabis plants are what most growers are after. It is these, after all, that produce cannabinoid-rich flowers responsible for cannabis’ iconic high.
So, how do you spot a female cannabis plant? Once they enter the pre-flowering stage (about 4–6 weeks after germination), their first pistils will appear at the nodes. The nodes are the parts of the plant where the branches meet the stem, and it is from these that female flowers (and male pollen sacs) will grow. Pistils appear wispy and white at first, before amassing into clumps of calyxes.
How To Determine if Your Cannabis Plant Is Male
Male cannabis plants tend to grow faster than females, and as such you may be able to identify their sex within 3 or 4 weeks of germination (or when plants have around 5 to 6 nodes). This gives you an extra opportunity to remove them before the females can be pollinated. However, if you don’t spot them, the pollen sacs will soon be mature enough to open and fertilise the females.
Like with females, male sex organs will appear at the nodes too. Unlike the fine white pistils of a female, male pollen sacs appear like small green balls, which then grow into bundles of pollen sacs. This distinction makes spotting them fairly easy, fortunately.
How To Determine if Your Cannabis Plant Is a Hermie
But how do you tell if your plant features both male and female sex organs? This depends on what type of hermie it is.
How To Spot a True Hermie
To spot a true hermie, you’ll look for the same signs as above. It’s likely the male organs will begin to develop a couple of weeks before the female. So, once you see pollen sacs developing, you can remove it. If it’s a hermaphrodite, pistils will appear a couple weeks later.
How To Spot Bisexual Flowers
This is much more difficult, and you have far less time to act. Pollen sacs appear and split open about a week or two after forming. This gives you ample time to spot and remove them. Bisexual flowers, on the other hand, will grow hard-to-spot stamen directly on the flowers. These tiny “bananas” are difficult to distinguish, and can pollinate immediately. It is worth investing in a pocket microscope to check your flowers out, else you could ruin your whole crop.
What To Do if You Spot a Hermie Cannabis Plant?
There are a few things you can do if you spot a hermie. These depend in part on what kind of hermie it is, and how far into the grow you are.
If you find a true hermie—those that develop separate male and female sex organs—the simplest solution is to remove the plant immediately. Either destroy it, or, if you have room, rear it in a sealed environment and harvest the seed-laden flowers.
Another option, which comes with the greatest risk but yields the greatest rewards, is to cut off the pollen sacs as they develop. If you’re careful, you can spot them long before they split, and you can remove them as you find them. Do this successfully, and you can harvest unpollinated flowers come harvest time.
If you find bisexual flowers during the flowering stage, you only really have two options (unless you want to let it pollinate your flowers). Either remove the plant, then kill it (or grow it in isolation); or, harvest it immediately. This second option is safe, and means you get some yield from the plant, even if it’s not the highest-quality bud you’ve ever smoked. It should be free of seeds if you catch it early enough, too.
Can You Smoke Hermaphrodite Weed?
If you opt to harvest your hermaphrodite plant, you can absolutely smoke it—though it is likely to be of worse quality than most bud. If harvested early, it will not be as mature, and thus less potent than mature flowers to boot. And if it’s developed seeds, the plant will have redirected energy to seed production, rather than trichome (THC, CBD, terpenes) production. Nevertheless, it should still get you high.
How To Avoid Hermies (in the Future)
Avoiding hermaphroditic cannabis is fairly simple if you control seed choice and the plant’s environment.
First, find marijuana strains that are not predisposed to hermaphroditism. Most commercially available feminized cannabis seeds (from good breeders) will almost always develop into females. In the same vein, don’t grow cannabis plants from seeds you’ve found in other flowers! These are likely to be the result of hermaphroditic pollination, and may well themselves become hermaphrodites.
In order to avoid bisexual flowers and the pesky bananas that come with them, treat your weed plants well! If growing indoors with a proper setup, this should be fairly simple. Just don’t stress them too much, and they should be fine. Outdoors, you have less control. Given that, hardier strains are more well-suited to outdoor growing, as it will take comparably more stress for them to develop into hermaphrodites.
Finally, ensure that you harvest the buds on time!
Taking Cuttings To Avoid Hermies
Another way to avoid hermies is to take a cutting from a healthy flowering plant. By doing this, the new clone will develop the exact qualities of the mother plant. It’s worth bearing in mind, though, that it’s still possible for environmental stress to trigger bisexual flowers in this new plant—but it won’t be a true hermaphrodite.
Note: You can’t clone autoflowering marijuana plants successfully.
How To Deal With Hermaphrodite Marijuana Plants
As a grower, it’s important to be aware of how hermaphroditic plants appear, and what to do if you come across them. But you shouldn’t live in fear of them. If you choose good-quality cannabis seeds, the chances of a true hermaphrodite appearing are slim indeed. And avoiding bisexual flowers is mostly within your control. Sometimes though, things go wrong.
If you do end up with hermies in your grow, acting fast is key to saving the rest of the crop from pollination. Check regularly, and when you spot them, remove them! Whether you harvest, grow, or kill them at this stage is up to you!
