A hermaphroditic plant, by definition, contains both female and male sex organs. Photo by: Gina Coleman/Weedmaps
Herming can occur when female plants experience conditions of environmental stress. “Female plants don’t actually turn male, they become hermaphrodites,” says Bruce Perlowin , CEO of Hemp, Inc . and seasoned cannabis cultivator. “You have a female plant that develops both reproductive parts so it can pollinate itself.” A hermaphroditic plant, by definition, contains both female and male sex organs .
What is herming, and why does it happen?
Elevated levels of female hormones in male cannabis plants can trigger female flowering development. The technique is more effective when applied to male plants that have not yet formed mature flowers. It’s also vital to bear in mind that many male marijuana plants are hermaphroditic plants, and distinguishing true males can be very difficult.
Author Robert Connell Clarke’s book Marijuana Botany An Advanced Study: The Propagation and Breeding of Distinctive Cannabis presents clear instructions for differentiating male and female plants. The gender of a cannabis plant is located at the nodes along the main stem.
Like all plants, however, cannabis has an inherent drive to procreate by propagating seeds. One way that the plant achieves this is by herming, when female plants become hermaphrodite to self-pollinate. The tendency to herm means that growers must take extra care to minimize any stressors that may cause the plant to perceive a threat and change its sex.
A good test to see whether the bracts have swollen is to take a pair of tweezers, grab one bract, and open it up. If there is a seed inside, you have a pollinated plant.
Male plants won’t show hairs at these nodes, but will develop little sacs of pollen. These pollen sacs will look like little balls. These balls can appear on their own or in clusters, depending how far into the pre-flowering stage the plant is. At some later stage of growth, the pollen sacs will burst open, spilling the pollen and possibly pollinating your females.
HOW TO AVOID POLLINATION OF YOUR FEMALE PLANTS
Pollination of your female cannabis plants will make them produce seeds and spend less energy on producing quality buds. But when you recognise the signs of pollination early, you can avoid putting time and resources into a poor harvest.
Among the early signs that your female has been pollinated is that her bracts become larger. Bracts are small, leaf-like structures that protect the female’s reproductive parts. These are the sites from which the flowering buds appear. Do not confuse the bracts with calyxes.
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.
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.
The space between nodes is called “internodal spacing” and will give you a sense of whether a plant will grow tall or short.
How to determine the sex of a marijuana plant
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.
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.
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.
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .