I have an indoor growroom and in my recent harvest I found seeds in the buds, but I’m sure there are no male plants in the room. I’ve heard that light leakage can cause plants to become hermaphrodites. Is this true, and if so, do you have any tips for avoiding this?
Cannabis plants are monecious. This means they have the ability to be either male or female. Or in the case of hermaphroditism, they can be both. The reason to make sure there are no males or hermaphrodites in your garden is because male flowers make pollen. When pollen touches the white hairs on a flower, it makes a seed, and seeded weed gives you headaches. Even though there are reasons in nature hermaphroditism could be important, such as continuing the species in case there is no male present, hermaphroditism is generally a bad thing when talking about cannabis plants.
Light poisoning is the most common cause for a normal plant to hermaphrodite.
Light poisoning refers to the flowering night cycle of a plant being unnaturally interrupted with light. The best way to prevent this is to close yourself inside your darkened room during the daylight, and then after allowing a few minutes for your eyes to adjust to the dark, check for any light leaks from covered windows, door jams, etc. Also cover all timer and appliance lights with tape.
Negative stressors can combine with small interruptions of the light cycle to cause hermaphroditism, especially with less-stable, clone-only hybridized strains. When the night cycle is abnormally interrupted, it sends a mixed hormonal signal to the plant. This can cause a full female plant to throw some male flowers. Male flowers are easy to identify, especially when side by side with female flowers. Male flowers look like small bunches of bananas, which will take a week or two to swell before they burst and release their pollen.
Finding a hermaphrodite in your growroom can happen at any stage of the flowering cycle and is indicated by the presence of male flowers growing on the same plant as female flowers. As with all species in nature this can occur in varying degrees. A plant can become slightly or majorly hermaphroditic. In cases where singular male flowers are found between the branch and stalk nodes, you should be diligently removing them as they grow. You must re-inspect the plant top to bottom every few days to be sure pollination and seeding doesn’t occur. If you find male flowers (anthers) actually growing from within the female flowers (buds) the situation is a little more dire. You can still remove all the male anatomy as it appears, but it will be harder to find and much more prevalent. This is a horrible discovery that leads to a tough decision: Should you let the plant live and risk the whole crop being ruined by seeds?
In either case, once hermaphroditism has compromised the safety and purity of your sensimilla, the plant should not be propagated further. Remember, once a hermy, always a hermy. The plant pictured here is in the tenth and what should have been the final week of ripening, but a timer failed and one light stayed on continuously for almost two weeks, causing this vegetative regrowth. Because the light was continuous, the plant made no pollen. This method of re-vegging can be used to save a flowering plant you have no copies of, but be careful, as this may cause some strains to hermaphrodite.
Purposefully causing a plant to hermaphrodite is called selfing. Gibberellic acid or colloidal silver is typically sprayed onto the female plant. This technique is used to make feminized seeds and uses the plant’s ability to be both male and female to force a female plant to produce male flowers. The pollen contained in these male flowers can only produce female seeds. Just keep in mind that feminized plants should not be used for breeding, as they were produced without a true male, making them genetically inferior.
Marijuana plant anatomy
The cannabis plant has several structures, many of which we can find on any ordinary flowering plant species. Cannabis grows on long skinny stems with its large, iconic fan leaves extending out from areas called nodes.
Cannabis really stands out in its flowers—or buds—where unique and intricate formations occur: fiery orange hairs, sugary crystals, and chunky buds enveloped by tiny leaves.
Parts of the cannabis plant
Seeds are produced in female cannabis plants and carry the genetics of a male and female. Seeds need to germinate to sprout and will grow a taproot, which will become the main root that anchors the plant.
These are the first leaves to grow from the seed after germination. They usually come in pairs, and seeing them is a sign of successful germination and that your plant is on its way to growing healthy and strong.
The roots grow down from the main stalk of the plant into the soil. When growing from a seed, the main root is called the “taproot.” Roots are the lifelines of a cannabis plant, pulling water and oxygen into the plant so it can grow healthy and strong.
Mycorrhizae, a beneficial fungus, can be added to soil to improve root systems.
The main stem, or stalk, of a cannabis plant grows straight up from the root system and supports all lateral branches. The stem gives a plant structure and stability.
Often, growers will top, or cut off, the stem after about five nodes, which forces the plant to grow out laterally more, creating more bud sites.
Branches grow out of the main stem and support fan leaves and buds. Growers often train a cannabis plant by topping branches to create more bud sites.
A node is a point at which a branch grows off of the main stem, or one branch from another branch. Fan leaves and buds can grow on some nodes, but not necessarily all.
When determining the sex of a cannabis plant, pre-flowers, or the beginnings of male and female sex organs, will appear at the nodes.
The space between nodes is called “internodal spacing” and will give you a sense of whether a plant will grow tall or short.
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
Fan leaves are the large, iconic leaves of the cannabis plant. They capture light for the plant and typically have little-to-no resin and are usually discarded when trimming.
Sugar leaves are the small, resin-coated leaves that buds form around. Sugar leaves are usually saved as “trim” during harvest and can be used for pre-rolls, extracts, and other cannabis products.
Also known as “buds,” the flowers of a cannabis plant are the fruits of your labor. They contain the cannabinoids and terpenes that get you high or offer health benefits. Flowers only grow on female cannabis plants and must be dried before consumption.
A cola, also called a “bud site,” refers to a cluster of buds that grow tightly together. While smaller colas occur along the budding sites of lower branches, the main cola—sometimes called the apical bud—forms at the top of the plant.
Bract and calyx
A bract is what encapsulates the female’s reproductive parts. They appear as green tear-shaped “leaves,” and are heavily covered in resin glands which produce the highest concentration of cannabinoids of all plant parts.
Enclosed by these bracts and imperceptible to the naked eye, the calyx refers to a translucent layer over the ovule at a flower’s base.
Stigma and pistil
The pistil contains the reproductive parts of a flower, and the vibrant, hair-like strands of the pistil are called stigmas. Stigmas serve to collect pollen from males.
The stigmas of the pistil begin with a white coloration and progressively darken to yellow, orange, red, or brown over the course of the plant’s maturation. They play an important role in reproduction, but stigmas bring very little to the flower’s potency and taste.
Despite their minute size, it’s hard to miss the blanket of crystal resin on a cannabis bud. This resin is secreted through translucent, mushroom-shaped glands on the leaves, stems, and calyxes.
Plants originally developed trichomes to protect against predators and the elements. These clear bulbous globes ooze aromatic oils called terpenes as well as therapeutic cannabinoids like THC and CBD. The basis of hash production depends on these trichomes and their potent sugar-like resin.
Male vs. female marijuana plants
Cannabis is a dioecious plant, meaning it can be male or female, and the male and female reproductive organs appear on different plants. What’s in your stash jar now are the flowers of a female marijuana plant.
Female plants produce the resin-secreting flower that is trimmed down into the buds you smoke, and males produce pollen sacs near the base of the leaves. Male plants pollinate females to initiate seed production, but the buds we consume come from seedless female plants—these are called “sinsemilla,” meaning “seedless.”
Growers can ensure the sex of their plants by growing clones or the genetically identical clippings from a parent strain. Feminized seeds are also made available through a special breeding process.
How to determine the sex of a marijuana plant
Cannabis plants show their sex by what grows in between their nodes, where leaves and branches extend from the stalk. Pollen sacs will develop on a male plant to spread seeds and stigma will develop on a female to catch pollen. You can see these differences weeks before they actually start serving their purposes in the reproduction cycle. These are known as “pre-flowers.”
Pre-flowers begin to develop four weeks into growth, but they may take a little longer depending on how quickly the sprouting phase occurs. By the sixth week, you should be able to find the pre-flowers and confidently determine the sex of your plant.
Examine the nodes of the plant and look for either the early growth of small sacs on a male, or two bracts on a female, which will eventually produce the hair-like stigma.
Female marijuana plants
Females are the prizes of cannabis plants—they are the ones that grow the buds that we all know and love. Anytime you see a picture of a cannabis plant with buds, you are looking at a female plant.
Female cannabis plants receive pollen from males to produce seeds, which will carry on the genetics of both plants to the next generation.
However, cannabis is primarily cultivated for buds, not seeds, so the practice of growing sinsemilla, or “seedless” cannabis, is prevalent today: Females and males are grown separately, or males are even discarded, to prevent pollination. This allows female plants to focus their energies on bud production instead of seed production.
Males and females are usually only pollinated when crossbreeding plants or creating new strains.
Male marijuana plants
Male cannabis plants grow pollen sacs instead of buds. Male plants are usually discarded because you don’t want them to pollinate the females, which will produce seeds—no one wants to smoke buds with seeds in it.
Males are important in the breeding process, but that is generally best left to expert breeders. When pollinating females, males provide half of the genetic makeup inherited by seeds.
Because of this, it’s important to look into the genetics of the male plants. Their shape, rate of growth, pest and mold resistance, and climate resilience can all be passed on to increase the quality of future generations.
Male plants can also be used for:
- Hemp fiber—males produce a softer material, while females produce a coarser, stronger fiber. The soft fiber from males is more desirable for products like clothing, tablecloths, and other household items.
- Concentrate production—males do have some THC and can be psychoactive, but much less so than females. Small amounts of cannabinoids can be found in the leaves, stems, and sacs, which can be extracted to produce hash and other oils.
What are hermaphrodite cannabis plants?
The rare hermaphroditic plant contains both female and male sex organs. These plants can sometimes self-pollinate, but this is typically bad as it will create buds with seeds and also pass on hermaphroditic genes.
“Herming out,” as some call it, is something that generally happens when a plant becomes excessively stressed. Some stressors include:
- Plant damage
- Bad weather
There are two types of hermaphrodite plants:
- A plant that develops both buds and pollen sacs
- A plant that produces anthers, commonly referred to as “bananas” due to their appearance
While both result in pollen production, true hermaphrodite cannabis plants produce sacs that need to rupture; anthers are exposed, pollen-producing stamen.
Because this occurs when cannabis is under stress, it’s important to monitor plants after they have been exposed to stressors: indoors, high temperatures or light leaks are often the cause; outdoors, a snapped branch might be repaired and then turn into a hermaphrodite.
The other primary cause of hermaphrodite plants lies in its genetics—a plant with poor genetics or a history of hermaphroditic development should be avoided to protect your garden. If you notice any pollen sacs or anthers at any point, remove the plant from your garden immediately to prevent pollination of female plants.
Is it bad to find seeds in your weed?
What does it mean to find seeds in your marijuana buds? Is it something to be worried about?
There’s a seed in my cannabis bud! What does this mean? Is it good or bad?
Sometimes you don’t see the seeds until they fall out of your buds
What causes seeds in buds?
Seedy buds are the result of pollination. What does that mean? Cannabis buds are flowers. Like other flowers, they make seeds when pollinated. Cannabis buds get pollinated when they come into contact with cannabis pollen while the buds are forming.
Seeds happen when pollen gets on the hairs (pistils) of buds as they’re forming. In other words, seeds in weed are caused by pollination.
This bud is full of fat seeds because pollen got on the pistils during bud development.
Pollen typically comes from the pollen sacs of a male cannabis plant. Male plants spray pollen everywhere when their flowers are mature. Sometimes female cannabis plants will produce pollen (known as herming) due to genetics or stress. Any source of pollen, whether the plant is male or female, can pollinate buds in the vicinity and cause seedy buds.
If you’ve found seeds in your buds, it happened while the plant was growing. Either the grower didn’t identify and remove all the male plants before they released pollen, or a herm was involved that self-pollinated or pollinated other buds in the grow area.
Does it mean the weed is bad?
Seeds in your buds aren’t good or bad. They are simply the result of pollination while the buds were growing. A few seeds here and there won’t make much difference in potency, though potency may be lower if the buds are very seedy.
The main problem with seedy weed is that you are getting less smokeable bud for the amount of total mass there. If buds are seedless, you get more bang for your buck. Seedless buds are known as “sinsemilla” (“sin semilla” is Spanish for “without seeds”) and are considered to be the highest quality and most potent type of weed.
Seedy weed is fine to smoke, though you should remove the seeds if possible (they have no THC and will pop if you smoke them). Unless there are tons of seeds, bud potency is unlikely to be affected.
Are “found” seeds good to grow?
I’ve seen some growers get impressive results with bagseed (seeds you find), but results may be hit or miss. Plants can grow in odd ways and the yields or quality may not be as expected.
The biggest problem is that seeds often don’t “breed true” to the buds that they came from. The resulting buds may end up nothing like the buds you found them in.
That is why many growers either stick to clones (which are exactly the same as the “mother” plant) or purchase seeds of a stabilized strain from a trustworthy breeder. This ensures each of the plants will grow the way you expect, and buds more consistently have the smell, yield and potency you expect.
If you’re not sure what strains to get, here are a few recommended favorites. These strains produce excellent weed and are generally easy to grow. Click the links for more information.
– top-shelf looks and smell with classic effects reminiscent of 90s buds but stronger. Easy to grow. – this version is MUCH more potent than regular White Widow. The buds tested between 24-26% THC. Don’t plan to do anything else that day ? – for those who are looking for a face melter. These buds test up to 28% THC and produce buds with quintessentially “American” looks and smell. The mental and physical effects may be too intense for most beginners. is a good choice for commercial growers with high THC up to 30%, big yields, and a short flowering time. is a potent Sativa hybrid with great yields and uplifting unique mental effects is an autoflowering strain that produces photoperiod-quality buds in about 70 days from seed to harvest.
Platinum Cookies is essentially a more potent version of the popular Girl Scout Cookies strain.
How can I tell if it’s a viable seed?
Mature cannabis seeds are typically dark brown or tan (the brown is a coating that can be rubbed off), and relatively hard. Very pale or white seeds usually won’t sprout.
However, I have been surprised to find some very flimsy or pale seeds sprout and produce amazing plants (we aren’t breeding cannabis for hard seeds after all). When in doubt, I highly recommend doing the true test to see if the seed is viable – try to germinate the seed and see if it sprouts !
The best way to tell if a seed is viable is simply to try germinating it
These seeds have germinated
These are all viable cannabis seeds. Every one grew into a healthy plant!