Introduction
It happens to the best of us: at some point, most cannabis cultivators have found seeds of unknown origin in their lovingly tended crop. You’re shaking your head in disbelief — what went wrong?
Whether you started with regular seeds and removed those identified as males before they had a chance to develop fully or began with cuttings from a known female or feminized seed, there’s still a potential for fertilization in your garden.
Since sinsemilla (‘unseeded’) cannabis is the most rich in beneficial phytochemicals, growers need to understand how this can happen and practice vigilance to avoid reduced yields.
First of all, cannabis is wind-pollinated. So let’s assume you’ve planted seeds made in a controlled growing environment where incoming air could not have carried pollen from an unknown, outside source.
Now, let’s pretend that somehow, a plant believed to be female managed to pollinate itself (and possibly others). Such individuals have been the ire of many a grower, and they’re often termed “hermaphrodites,” “hermies,” or “herms.”
So, what are cannabis hermaphrodites? And how can you identify and deal with them in your garden? Let’s get into it.
TL/DR
We have been taught to think of cannabis as being either ‘male’ or ‘female’ plants, but cannabis with mixed sexual expression exists as part of nature
Genetics and environment affect the chances of finding a ‘hermie’ in your grow
Learn to identify the two types of cannabis anatomy that can release pollen: “male” flowers and “bananas” (anthers)
Limit the stress your cannabis plants experience throughout their lifetimes
Inspect your garden when traumatic events occur and throughout the flowering period
Immediately and carefully remove any possible source of pollen to prevent seed production
Table Of Contents
Aren’t Cannabis Plants Either Male or Female? Is it Not That Straightforward?
Why is it Important to Identify Mixed-Sex Expression (Hermaphrodite) Cannabis Plants?
What is the Difference Between a True Hermie and Bisexual Flowers?
What is the Difference between Monoecious and Dioecious Cannabis?
To Avoid Mixed Sex Expressions, Choose Your Cannabis Cultivar Genetics Carefully
To Prevent Hermies in Your Grow, Avoid Stressing Your Plants
Should I Grow the Seeds I Find as a Result of Mixed-sex Expression?
Aren’t Cannabis Plants Either Male or Female? Is it Not That Straightforward?
In reality, no. You probably understand that plant biology is very complex. Even though it’s endlessly fascinating, scientific specificity and accuracy in the language of cannabis haven’t been most people’s priority under prohibition. To help more folks learn to grow and enjoy cannabis, grassroots communities adopted generalized ways of grouping cannabis.* They didn’t assume a more complex understanding of breeding (sexual reproduction) than is usually taught in school or shared in conversations about “the birds and the bees.”
Now that DNA analysis and genomics have entered the common conversation, we know how complicated, diverse, and changeable biological sex expression is in nature.
But you probably didn’t come here to take a deep dive on cannabis botany, nor on its history, economy, and related linguistics — you want to know how to get the most out of your grow! For the sake of getting on with the discussion, let’s allow for a little blunting of the terminology.
What is a Hermaphrodite Cannabis Plant?
Put simply, a plant with parts that both release pollen (staminate, “male”) and that receive pollen (pistillate, “female”) to reproduce.
Words used for cannabis plants with the ability to self-pollenate include “hermaphrodites,” as well as “monoecious,” “bisexual,” “co-sexual,” and various slang terms such as “herms,” or “hermies,” You might also find people referring to plants “herming out,” or “turning male.”
Comparing the characteristics of male, female, and hermaphrodite plants.”
Why is it Important to Identify Mixed-Sex Expression (Hermaphrodite) Cannabis Plants?
To prevent incidental pollination and maximize your cannabis harvest yield and quality!
By now, you’re probably well aware that unfertilized pistillate flowers are the most concentrated source of THC, CBD, and other target phytochemicals (the beneficial molecules that make cannabis such a delightful and effective plant).
When is it Crucial to Check your Plants for Hermaphrodites?
You absolutely must check for signs of mixed-sex expression if your plants experience a major trauma. Equipment failures, grower errors, and extreme weather are common causes.
Equally important is inspection as your planned harvest date approaches. Season length estimates provided by seed companies are usually pretty reliable, but the occasional outlier will reach its peak sooner than you’d expected. If left in the garden, especially in optimal summer flowering conditions, this plant may be prompted to develop a few anthers to try and produce seeds while the growing is still good.
In general, check for signs of a plant’s ability to pollinate your garden as soon as it is mature enough to start flowering. Although home testing kits are now available to identify the self-selected sex of a plant as early as seven days after it has germinated, you can start visually inspecting for indications of sexual differentiation once the leaves of the fourth node emerge.
Without a microscope, don’t be surprised if you can’t see anything yet at that stage. It’s usually a while longer before you can confirm plant flower type by unaided sight.
What Causes Cannabis Plants to Present as Hermie?
The answer to this question combines nature (genetics) and nurture (lived experience).
Some Genetics Tend to Herm More than Others
Hermaphrodite plants may be more common in certain cultivars. In other words, some plants are just more likely to express a mixed sexual presentation. It’s in their DNA. (see “What is the Difference between Monoecious and Dioecious Cannabis?” below).
Cannabis seeds produced for high cannabinoid harvests are created by breeding pairs of plants chosen for being very strongly self-directed to perform one sexual role and for being able to do it well. Although the science isn’t entirely in on this yet, we know that by the time a seed has germinated, the plant has pretty much set its course for what type of flowers it will eventually grow.
This is known as “stability” and is one of many traits breeders seek to “lock in” to their varietals. It makes growing good quality cannabis easier. Yields are increased when large, very robust inflorescences (the branches on which flowers grow, aka “buds”) are harvested without having been pollinated.
Lived Experience Influences the Plant’s Development
A cannabis plant sensing a threat to its life can do something remarkable: pollinate itself!
Cannabis is a “sexually labile” species, meaning it can change its sex expression. This is an evolutionary advantage; it can make differently-sexed flowers upon receiving information from its environment that suggests without doing so, its genetic line will not continue.
Environmental stress can come in many forms. Indoor and outdoor growers have different challenges when maintaining optimal conditions. Careful nurture allows the plant to focus on fewer tasks. A lot of energy is diverted from other processes when a plant has to start growing a new type of flower. This loss directly reduces total yield.
Stress factors that have been connected with an unexpected sexual development in cannabis include:
Lighting
Low/inadequate lighting
Sudden changes in the lighting schedule
Disruption of dark period (breaking the plant’s circadian rhythm) or not providing any dark period (24h of light)
Bodily Damage (especially to Roots)
Over-foliation (the removal of too many leaves at one time)
Physical injury during transplantation
Drying from lack of water
Root exposure to light (using white pots or from soil erosion)
Soil compaction or standing water that prevents roots from breathing
Nutrition Issues
Lack of nutrients appropriate to the stage of life
Inability to access or absorb nutrients
Salt accumulation
Air Quality and Temperature
Excessive heat due to ventilation/circulation problems
Sudden drops in temperature
How do you Identify Hermaphrodite Cannabis Plants?
When you’re working with what you already believe to be female plants, look for anatomy that can release pollen. These may be staminate flowers or exposed anthers.
Staminate flowers:
Light green or white, sometimes tinged with purple
Oval-shaped
Open to reveal stamens
Pollen sacs appearing on a female cannabis plant.
Anthers:
Bright yellow
2-3mm in length
Look like bananas that unfurl between the stigmas (the white, pollen-receiving “hairs”) of neighboring pistillate flowers.
Banana-like formations on cannabis plants.
What is the Difference Between a True Hermie and Bisexual Flowers?
A “true hermie” appears to have fully-functional male and female flowers. True hermaphrodite plants are what some folks call monoecious cannabis.
“True” refers to the full development of a flower that can open and reveal multiple reproductive organs. These male and female flowers are fully functional. A staminate, “true male” cannabis flower looks like an oval-shaped ball attached to the plant by a little stem. It opens up to allow dangling stamens to catch the wind and disperse its little packages of genetic material.
Difference between Hermaphrodite plants and Bananas
A “bisexual” flower is what some call a bud that has been observed as one sex but later turns out to have been composed of both pollen-receiving and pollen-releasing parts.
A “bisexual” cannabis plant can look like a female plant but behave like male plants by pollinating others. When a “true female” inflorescence starts making anthers, the surrounding pistils (the little white hair-like parts) can be pollinated and grow seeds. Strong air currents and gravity disperse the pollen from anthers to others nearby.
The difference between banana-like structures and pollen sacs.
What is the Difference between Monoecious and Dioecious Cannabis?
Historically, cannabis has been understood to be “dioecious.” The word comes to English by way of Ancient Greek, meaning that a species population of plants can be divided into “two houses” according to reproductive roles. This is what people mean when they say there are “male” plants and “female” plants and flowers.
Most cannabis plants are genetically inclined to grow this way, outwardly displaying the traits of being either a pollinator or a seed producer, but not both. It makes it possible to grow sinsemilla and be very selective in breeding by creating sex-segregated gardens. In cannabis cultivation for more “hemp”-style uses (e.g., fiber and seed production for food oil and protein), monoecious cannabis is popular among farmers. This is “one house,” or plant that will take on all reproductive roles from the outset of its growing journey. It will operate, on a biological basis, to divide resources in service of growing “true male” and “true female” flowers naturally together.
Monoecious presentation is a recessive trait in cannabis. If genes from monoecious plants were to enter the pool from which your cannabis was bred, there is a chance for monoecious presentation. It’s extremely unlikely you will encounter monoecious cannabis unless you live and grow outdoors in proximity to farms where it is grown and save or collect seeds from unknown pollen sources.
Can “Male” Cannabis Plants Herm?
You bet. Since most medical/recreational cannabis growers are concerned with keeping only pistil-producing plants, there is less cultural conversation around mixed-gender flowers on plants that have shown signs of being predominantly male.
Those plants generally reveal their sex expression earlier and are killed before the grower learns whether they might have also developed pistillate flowers. They, too, can be either genetically monoecious or express both sexes due to stress. Rest assured, so-called “male hermies” exist too!
To protect your plant from some basic stresses, such as pests, and make sure that they receive the correct amount of nutrients, we recommend to purchase our Plant protector. These will form a first line of defense against a lot of common stresses.
Bergman’s Plant Protector
Protect your plants from diseases and harmful pests.
Consists of three 20 ml bottles
Enough plant protection system supplies for up to 20 plants
Suitable for soil, hydroponic and all other grow mediums
What To Do If You Spot a Herm in Your Cannabis Grow?
Act Fast to Avoid Pollination!
As mentioned, you get a higher production of target cannabinoids from unpollinated plants. Part of being able to act fast is diligent inspection: you literally want to “nip it in the bud” before potentially millions of pollen grains (one flower alone can release about 350,000!) are circulated. Make more room for the plants that remain and conserve your resources.
Turn off Ventilation
If you are growing indoors and have identified potential hermies in your grow, immediately switch off anything causing a current that could carry pollen to exposed stigmas.
Isolate the Pollen from your Female Plants
Wear nitrile (or similar) gloves and use a handheld water sprayer at close range to wet any exposed anthers you see (you’re aiming for less of a mister, more like a water pistol). The water will capture pollen that it comes into contact with, stopping it from reaching your pistillate flowers.
Use a large bag, the type made for collecting grass or leaves outdoors, and cover the whole plant. Cinch the bag closed around the stalk and cut it off below the lowest branches.
Clean off your gloves when handling a known pollen-producing plant and others in the garden. Inspect the rest of your plants, paying especially close attention to those with the same genetics as the one that you had to remove.
Pollen floating through the air near a marijuana plant.
Perform a Dip
Do not open the bag(s) again until you are in a place where errant pollen cannot escape and be recirculated into your garden. Perform a “dip” (a common practice for sanitary cannabis harvesting) by dunking the same plant in a slightly basic solution (a few drops of H202 will do it) or plain water. This should hopefully catch any pollen that could have already dropped onto leaves and any from anthers you missed in your original inspection.
Reinspect Plants and Check Environmental Controls
Whether or not you think you know why your plants went into “survival mode,” take the cue to follow back all the possible causes. Starting from the site where you found the cosexual plant, evaluate all of your gear for blockages, burnouts, drainage issues, etc. Check that all your timers are working properly, take temperature readings, and if you have automatic data collection from sensors or cameras, review those materials, too.
Act Fast, Keep Calm, and Keep Truckin’ On!
Know the expression “the road to hell is paved with good intention”? Sometimes, an overcorrection causes just as much stress as the original issue, now compounding the experience of unpredictability. Keep Calm and move slowly. If you recently “fixed” a problem, double-check your resolution.
How To Prevent Herms in Cannabis
First of all, to avoid growing hermaphrodite marijuana plants, work with proven genetics, such as cannabis strains from ILGM, and keep stress to a minimum throughout the life cycle of your plants.
To Avoid Mixed Sex Expressions, Choose Your Cannabis Cultivar Genetics Carefully
Using high-quality feminized seeds from a trusted source, such as ILGM strains, is the first step to ensuring your genetics were developed by people with your needs in mind.
In the competitive cannabis market, pollen management is a big concern. Making highly consistent and productive seeds means they must hold up to incidental stresses without reduced yield. Professionals test their seeds before selling them to ensure their customers have a predictable crop.
Reputations are built on customer experience and feedback. Experimental or mystery seeds of unknown ancestry could be your favorite thing you’ve grown this year. They may also have a tendency toward hermaphrodite expression if it is programmed into the genes (possibly the reason those seeds turned up in the first place).
Top Tier genetics
If you’re not looking to experiment with developing genetics and just want to grow top-tier cannabis like you’d buy from a trusted source, choose time-honored varietals, like Northern Lights, Blue Dream, GSC, amongst many others.
Pro Tip: For quality control purposes, the vast majority of available seeds are made in tightly managed indoor environments. Your plants will experience more variable conditions if you’re an outdoor grower. The natural setting will help prevent some kinds of stress (the rise and set of the sun aren’t affected by a power outage, unlike lights on a timer) while also posing some difficult-to-manage challenges (like an early frost).
Before releasing a new seed to the public, stress testers check to see if the variety can withstand these types of shocks — within reason. They might, for example, hit the roots with some ice water. Mangling branches and partially uprooting a plant to mimic surviving a hurricane, on the other hand, could be more intense than what they’re willing to put their plants through.
For this reason, outdoor growers could find mixed-sex expression in otherwise hardy genetics. So, even if you’ve grown the same seeds inside with no problem, it doesn’t mean you can slack on inspections!
To Prevent Hermies in Your Grow, Avoid Stressing Your Plants
Think of the ways you, as a living organism, experience stress. Hunger, malnutrition, dehydration, overheating, feeling too cold, not getting enough air to breathe, being trapped, and rough handling can all make you feel threatened and reactive.
Those same sensations are stressful to cannabis. Obviously, how a marijuana plant handles stress is different from human ones. It’s your job as the grower to learn and understand how to provide the least stressful experience of life you can.
Create consistency through regular monitoring of environmental conditions, and trust your cannabis to regulate its biological processes, including sex expression.
Can I Still Harvest and Consume Hermaphrodite Weed Plants?
Yes, absolutely! Will it be the greatest cannabis you’ve ever had? Unlikely.
How you’ll best use any cannabis plant after you chop it down depends on how mature it was when harvested. The cannabinoid content of a hermaphrodite plant depends on when you identify it as having pollen-bearing parts.
Late-season stressed plants, with only a few sets of anthers emerging, may be on their way to good cannabinoid yields – but if they’re overripe, the peak THCA harvest dates may have passed. If you see these, cut them down and post-harvest process them as usual.
If you removed one mixed-sex plant early to save the yield of your other plants, that young individual will not contain much in the way of the target cannabinoids you were hoping to harvest. However, there are still health benefits from eating vegetative cannabis.
If you don’t consume them yourself, feed them to plants: they make good fertilizer for future crops!
Should I Grow the Seeds I Find as a Result of Mixed-sex Expression?
I would (the curious cat that I am), particularly if I thought I could avoid the stress that induced the change in the future. If they were dioecious plants, the good news is the seeds will have inherited a set of chromosomes genetically inclined for strong ‘female’ presentation. If the seeds only had a singular parent (there’s no chance the pollen came from another errant anther elsewhere in the garden), they should grow almost like a clone of the marijuana plant they came from.
A Note on Language
While cannabis plants aren’t people, it’s common and fairly forgivable that we talk about them in terms that make sense to us. We sometimes fall into the habit of ascribing human emotions, like how the expression “herming out” parallels our notion of “stressing out.”
The reverse is also true: how we talk about plants can reveal how we think and feel about ourselves and other people. Language in cannabis spaces is always evolving. In English, especially in particular contexts, it unfortunately continues to be affected by racism, sexism, and other anti-scientific and reductionist concepts.
Words have power. “Hermaphrodite” is now antiquated as a slur against people who are intersex, but some may still find it jarring to hear or read, even in the strictly botanical sense. So despite its ‘value-neutral’ origin in scientific classification, the continued use of the term is becoming less popular in favor of equally valid terms like ‘mixed-sex’ or ‘cosexual.’
Final Thoughts
Cannabis genetics, including how sex expression is determined and what can make it change, is a study that is very complicated by human intervention. We’re always learning more about what can and can’t be controlled and observed through traditional agricultural techniques and modern work with DNA.
Also, adversity isn’t always a bad thing. Historically, cannabis growers have learned to use techniques that push the boundaries of plant comfort in service of higher yields. This includes growing under artificially longer periods of light, steering crops with nutrients, and strong pruning. Some even have the word “stress” in them (for example, low-stress training). Try to find a balance where changes you make are gradual, not traumatic, and allow your plants to adapt.
Explore the other grow guides on our site to fine-tune your understanding of how to grow exceptionally healthy cannabis. Don’t miss out on opportunities to learn by keeping good records and doing close observation. Use your senses and any additional tools available (e.g., meters, sensors, home test kits, and lab analysis) to enjoy and deepen your relationship with this amazing companion species.
Until next time, may you and your garden grow together ever higher!
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