Cannabis Hermaphrodites, Stress Testing

Cannabis Hermaphrodites are no fun to work with and could seed your whole crop.
The goal of a cannabis pheno hunt isn’t just to find plants with outstanding qualities it is also to find sexually stable phenotypes. Therefore, stress testing is one of the most important parts of every successful pheno hunt. Whether you are a commercial growers, a hobby grower or a breeder, working with pure, sexually stable females will turn out to be crucial.
In this tutorial we’ll first debunk some of the myths surrounding cannabis hermaphrodites. Then we will go over some useful tips on how you could effectively stress test your cannabis plants.

Cannabis Hermaphrodites

I Cannabis Hermaphrodite Myths

Myth 1: Feminized Cannabis Plants Aren't As Sexually Stable As Regular Cannabis Plants

This is one of the biggest myths out there. It stems from how some breeders used to create feminized seeds using pollen from hermaphrodites. That method was called rodelization. Nowadays most cannabis breeders resort to either colloidal silver (CS) or silver thiosulfate (STS) in order to “reverse” their female plants. If the females the breeders use are sexually stable, the plants coming from these female seeds will be more sexually stable than most regular strains. The reason for that greater stability is because it is easier to stress test a female than it is to stress test a male.

Myth 2: Cannabis Hermaphrodites Are Rare And Most Cannabis Plants Are Sexually Stable

Cannabis hermaphrodites are much more common than one might think. In fact, most cannabis plants have hermaphroditic tendencies. However most either go unnoticed or require very stressful conditions in order to reveal themselves.

Myth 3: Hermaphroditism Is Due To Stressful Growing Conditions

No matter how skilled you are at tending your garden you are always at risk of having some of your plants herm. This is because hermaphroditism is already present within the plant’s DNA. Although stressful conditions cause most plants to reveal their intersex tendencies, highly sexually stable plants will not herm even when under stress.

Myth 4: Landraces And Wild Cannabis Varieties Do Not Herm As Much As Modern Strains

It is quite the opposite. For many landraces and wild plants, having the ability to turn hermaphrodite is a survival mechanism. It allows the plants to reproduce even when there are no males or females around.
As hermaphroditism is an undesirable trait, many modern breeders have helped increase the sexual stability of most modern cannabis strains.

II Stress Testing Tips

Here are 7 simple tips you can easily apply in order to force your plants to reveal their hermaphroditic tendencies:

1. Grow Your Plants Indoors

Outdoor plants almost never show their hermaphroditic tendencies. However the same plants grown indoors could easily grow some “nanners” or “ball sacs”.
That is because indoors, the light spectrum isn’t the same as the sun’s. Likewise the root ball of the plants is at room temperature whereas outdoors, it is often cooler than the air. The light cycle and the soil composition are also different. All these factors cause a lot of stress to the plants thus explaining why plants herm much ore often indoors.

2. Use Small Containers For The Entire Life Cycle

When your plants become slightly root bound, the extra stress may help reveal the hermaphrodites.

3. Raise The Temperature Of Your Grow Room

The heat test is one of the most effective stress tests. Cannabis plants like about the same temperature as humans do. The optimal temperature range for flowering plants is between 65 and 80°F or 18 to 26°C. Raising the temperature to over 85°F can trigger a strong stress response. This test is so effective, it can even work for some male plants as well.

4. Give Your Cannabis Plants Too Much Nitrogen

This is one of the tricks some old breeders used back in the day in order to make seeds with the rodelization method. A slight nitrogen overdose can often cause the sneaky hermies to reveal themselves.

5. Over/Under Water Your Plants

Causing a water stress on purpose is tricky as the growth of your plants will be stunted, and an over watering can easily kill cannabis plants. However, if you are an experienced grower, you can put your cannabis through moderate water stress.

6. Let Your Cannabis Finish Under 24 Hours Of Daily Light

Cannabis hermaphrodites that are easy to spot generally grow ball sacs at the beginning of the flowering cycle. However, the sneakiest hermies develop some tiny “nanners” hidden within the buds. To make matters worse, they generally do so at the very end of the flowering cycle. That is why so many of them go unnoticed. The best way to force these to reveal their hermaphroditic tendencies is to give the plants 24 hours of light per day at the end of the cycle. This is the ultimate stress test. When you do so the plants will not revert back to a vegetative stage for at least 7 to 10 days. That way you could still harvest the plants afterwards. However, it is recommended to keep the plants in 24/0 for 2 weeks.

7. Let The Plants Flower Past The Harvest Date

Resort to this technique in addition or instead of letting your cannabis plants finish under 24 hours of light. When female plants are past their life cycle, some of them will start producing male flowers as a last ditch attempt to reproduce before dying.

III Frequently Asked Questions

How To Stress Test Auto Strains?

Unlike photoperiod strains, Autos naturally flower during the summer, when the days are long. Therefore you can stress test your autoflowering plants by giving them 12 hours of daily light instead of the recommended 18 to 20 hours of light per day.

How Many Plants Should You Grow?

Because pheno hunting is a numbers game, the more plants you grow, the higher your chances of finding a stand out specimen that will be sexually stable. However, this also depends on the strain. As we talked about before, landraces generally herm more often than modern strains. Therefore, if you are doing your cannabis pheno hunt with a landrace variety, you should work with a larger population.

What Is The Best Way To Spot Cannabis Hermaphrodites?

Here is a great tool you can use to easily spot the Hermaphrodites, the Headlamp!  It is cheap and very effective. Inspect your plants in the dark to make the sneaky male flower stand out from the female floral clusters.

Preventing Hermaphroditism

If you can only grow a limited number of plants and are looking to do a pheno hunt, then you should avoid all types of stress.
Do the opposite of what we talked about in this tutorial and your cannabis plants will be much less likely to herm.

Cannabis Hermaphrodites Conclusion

If you stress test you cannabis plants thoroughly, you can expect the plants that pass these tests to be highly sexually stable. These plants should not herm even under stress and if you use them for breeding, they will pass on that high sexual stability to their offspring.
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2 thoughts on “Cannabis Hermaphrodites. Stress Testing Your Plants.”

  1. Really interesting article! Very informative, thank you.
    It worries me that yours is the only easily accessible article I found on this subject. If you are the only person writing about it, how can we be confident that adequately stress testing new varieties is a common practice among reputable seed banks?

    1. Hello Benjamin,

      It’s one of the main reasons why we got into breeding, because it was rare to find strains that are truly sexually and genetically stable.
      Some breeders do all their breeding outdoors and others sometimes hurry to get their new trendy “strains” to market without putting in the work (Stress tests and stabilization of the lines) while others completely decentralize their seed production.

      Fortunately, there’s still some serious breeders out there such as ACE, Ethos, DJ Short… but it is a minority.

      Thank you, I am glad you found the article interesting!!

      Best,
      Al & the Khalifa Team

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