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Hermaphrodite weed plants - why do they happen and what can you do to avoid them?
There is little more annoying than finding out halfway through a grow that you have a tent full of hermaphrodite weed plants. Or even one hermaphroditic plant, as it can ruin your entire crop. But what exactly is a hermaphrodite cannabis plant? And can you avoid breeding such specimens?
Cannabis is basically a dioecious or ambiguous plant species. That actually means nothing more than that the male flowers and the female flowers are on different plants. The pollen from the male plants reaches the female plants through the air, after which seeds are formed in the female flowers. At least that is the standard way of fertilising cannabis plants.
When cannabis is grown indoors, it is preferable to leave it unfertilised. Once cannabis plants have been fertilised, they will stop producing flowers and devote their energy to producing seed. A fertilised cannabis plant is, therefore, less potent and produces less cannabis than an unfertilised cannabis plant. The Spanish term sensi milla stands for strong, potent weed and literally means “without seed”.
What is a Hermaphrodite cannabis plant?
Monoecious, or unisexual plants also occur in cannabis plants in some cases: male and female flowers on a single plant. This is an evolutionary survival strategy that allows cannabis plants to reproduce in an emergency, even when there are no males around. However, there are two causes for a female cannabis plant to produce male flowers. In some cases, stress causes a cannabis plant to become a hermaphrodite, and in other cases, cannabis plants have a genetic predisposition to it.
The issues with feminized seeds
To understand why hermaphrodite cannabis plants are often associated with feminized marijuana seeds, you need to know how feminized cannabis seeds are made. This is the short version: a female plant is intentionally stressed with a particular substance by a grower. This is often gibberellic acid, but silver water and other substances are also used. The stress causes the female cannabis plant to go into a kind of emergency mode and to produce male flowers.
Because the female cannabis plant only has x chromosomes (sex chromosomes) and a male cannabis plant has both x and y chromosomes, the pollen determines the sex of the seed. In a normal situation, the seed principle has received an x chromosome from the parent plant, and either an x or a y chromosome from the parent plant. However, when the pollen comes from a female plant, it always contains an x chromosome and never a y chromosome, for the simple reason that female cannabis plants do not have y chromosomes. The seed that results from this always has two x-chromosomes (one from the hermaphrodite pollen, and one from the mother plant in which the seed grows) and will therefore always be female.
To make feminised cannabis seeds, female cannabis plants are deliberately made hermaphrodite.
Related article: how to make feminized cannabis seeds
So with a feminized seed, one of the parents is always a hermaphrodite. But because it is not hermaphrodite in nature, but is made by a substance hermaphrodite, it does not necessarily have genetic potential for hermaphroditism. However, the way in which seed companies select their plants and have female plants make pollen, can ensure that hermaphroditic plants occur more often with feminised cannabis seeds.
It should be clear; you cannot completely prevent hermaphrodite cannabis plants. Yet it must be said; although the chance of hermaphrodites with good feminised seed is almost nil, to completely prevent hermaphrodites in your grow room it is best to use regular seed or take cuttings from a regular female cannabis plant. If you are an amateur grower, you don’t worry too much about it; if you grow less than the tolerated number of five cannabis plants, you will have that one sporadic hermaphrodite out in no time.
How to recognize a Hermie weed plant?
Although the chance of a hermie is limited, it is important to spot a hermie in an early stage. This way you prevent a lost harvest. So how to recognize a hermie?
The appearance of bananas
When your plant is developing bananas at the beginning of the flowering phase, your plant is a hermaphrodite.
When a cannabis plant has a genetic predisposition to become a hermaphrodite, it does not stop with a single “banana” at the end of the flowering phase. A “real” hermaphrodite produces male flowers from the beginning of the flowering phase. These are not only the pistils but real buds as you also see with male cannabis plants. So always pay close attention to when your cannabis plants start their flowering phase. You can’t really do anything with hermaphrodite cannabis plants. The female flowers are full of non-smokable male flowers, and when the male buds open, the hermaphrodite will fertilise all surrounding female plants and ruin your “sensimilla”. If you see a hermaphrodite, remove him (or her) as soon as possible.
Fortunately, many cannabis strains are not genetically hermaphrodites, but nevertheless produce a few male pistils – sometimes referred to as ‘bananas’ because of their shape – at the end of the flowering phase. These are not full male flowers, just a few pistils. These look like little bananas that usually poke out harvest-ready buds. Because the female plant is aware that she is approaching the end of her life cycle, but still has not fulfilled her life purpose (reproduction), she will fertilize herself out of necessity.
Spotting Bananas by the end of the flowering phase
As a grower, you don’t really have to worry much about cannabis plants that produce a few bananas at the end of their flowering phase. The bananas are usually only a few and are actually too late for the plant to form real seed. The flowering phase is almost over when you see the bananas, and you can simply harvest and smoke. After a round of bananas, make sure you clean your grow room thoroughly because the bananas from one round can still fertilize the buds of the next.
Although all hermaphroditic cannabis plants have been created at some point by some form of stress, hermaphroditism can also be a genetic predisposition. You can imagine that if you allow hermaphrodite plants to reproduce, the next generation will produce more hermaphrodites. Feminising cannabis seeds also entails a risk of hermaphroditic plants.
How to reduce the chances of hermaphrodite plants in your grow?
Various things can shock your cannabis plants and become hermaphroditic, so it is good practice to avoid these factors; which include light leaking into the grow tent during the dark parts of the light cycle in the flowering stages. Issues with the fertiliser, temperature and pH levels can also lead to the plants growing male sex organs. Watering too much or too little can shock your plants as can leaving it too late until harvest. Cannabis plants are quite sensitive, so if you are going to make any alteration, it is best to do it gradually, especially when growing weed indoors, where hermaphroditic plants are more of an issue in any case.