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Techniques to avoid hermaphrodites when growing from feminized cannabis seeds

feminized cannabis seeds herms hermaphrodite

Let's face it, people buy feminized cannabis seeds for the convenience. They take the inconvenience of having to deal with the additional space, light and nutrition requirements when you are growing from regular cannabis seeds.

But feminized cannabis seeds can present problems for some cannabis growers at times. There can be many causes for feminized cannabis seeds to turn hermaphrodite - we will explore the reasons and background as we go through the detail of this interesting facet of feminized cannabis seeds.

First, lets understand what a hermaphrodite is.

Cannabis, has distinct male and female plant types that result from any typical regular cannabis seed.

Usually, in nature, the ratio of male to female is usually 50 / 50. However in certain circumstances these ratios are altered.

What that reveals, is that environmental factors can impact the sex of cannabis plants.

For example, the ratio of males to females can be altered if the root zone temperature is warmer, or if the hours of light for seedlings is greater than 16 when the plants are very young.

What these environmental factors are doing, is stressing the seedlings in some way so that the average ratio changes away from 50/50 to something else.

Is it true that hermaphrodites in feminized cannabis seeds are based solely on genetics?

No, this is untrue. As a matter of fact, all cannabis seeds have the potential to exhibit hermaphrodite or intersex traits.

Cannabis is a plant where in its natural state, it is possible to have both males and female blossoms on the same plants.

In some strains of cannabis, hermaphrodites are a common part of the population. In hybrids, indicas or sativa, there is a tendency towards being able to host flowers of both sexes on the same plant, in some specimens within a large volume of plants.

This is an inbuilt mechanism of the plant to avoid becoming extinct. It is a survival mechanism.

When it comes to feminized cannabis seeds, we know that if they are produced well, that they are going to be mostly 100% female to begin with.

However, similar to regular cannabis seeds, feminized cannabis seeds are also impacted by environmental factors from the seedling stage.

Where a regular cannabis seed is affected, it may change to either more males or more females depending on the type of environmental stimuli. Regular seeds can also produce hermaphrodite plants depending on the type of environmental stimuli.

But when it comes to feminized cannabis seeds, when there is an adverse environmental stimuli, they cannot fully change their sex because of how they are bred, so they respond to the stimuli by making some male flowers amongst their mostly female blossoms.

Usually this happens mostly at the time when the plants are starting to bloom, especially in artificial light situations. There can also be late stage male flowers but this is common to both regular and feminized cannabis seeds.

This can happen to any feminized cannabis seed, irrespective of the genetics or breeder.

Even the highest quality feminized cannabis seeds can be turned hermaphrodite given the correct environmental and or chemical triggers.

So, how do you reduce the chances of hermaphrodites when using feminized cannabis seeds?

  1. Sprout seeds under 14 hours of light a day, only increasing to 16 hours gradually once the true leaves have grown two full sets.

  2. Grow the plants in vegetative stage until they show pistils - usually 4 to 5 weeks minimum

  3. Do not change the artificial light schedule from the vegetative schedule to the flower schedule abruptly, rather, do it gradually over a number of days

  4. Do not over prune the plants at any time. Some feminized cannabis seeds can be stressed by over pruning, causing them to exhibit some male flowers

  5. Avoid extreme temperatures, both hot or cold for your indoor environments

  6. Avoid interruptions to your artificial lights and ensure that your timers are correctly programmed and working as expected

  7. Avoid excessive bending, scrogging or knuckling as this changes the hormones present at the tips of the plant and can lead to male flowers at internodes in feminized seeds

  8. Avoid overly concentrated nutrient mixes if running with coco or hydroponics

  9. Avoid excessive EC and PPM in hydroponics

  10. Avoid excessively acidic root zones

What chemicals or plant hormones promote male flowers in feminized cannabis seeds?

  • ethylene inhibitors - silver, cobalt, aminoethoxyvinyl (AVG)

  • gibberellins

  • boron


We've looked at how environmental factors affect feminized cannabis seeds and learned the reasons and circumstances under which feminized cannabis seeds may tend to show hermaphrodite traits.

To assist growers to avoid these issues we've gone through ten steps to avoid hermaphrodites when growing from feminized seeds.


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