Cannabis plants, also known as dioecious for the botanically-inclined, exhibit gendered characteristics. Among them, female plants are highly valued for their ability to produce buds rich in cannabinoid content. To ensure the best yield, growers strive to maintain crops free of male plants to prevent pollination of the female buds.
Despite this effort, all cannabis plants have an inherent drive to reproduce and propagate seeds. One intriguing way they achieve this is through a process called herming. When subjected to certain environmental stressors, female plants can become hermaphrodite, meaning they develop both female and male reproductive parts, allowing them to self-pollinate.
Bruce Perlowin, CEO of Hemp, Inc., and an experienced cannabis cultivator clarifies that hermaphroditic plants do not actually change their gender; rather, they develop both sex organs simultaneously to enable self-pollination.
For growers, the tendency of cannabis plants to herm underscores the importance of providing optimal growing conditions and minimizing stress factors. By doing so, they can help prevent the plant from perceiving threats and shifting its sex, ensuring a higher chance of obtaining desirable, unpollinated female buds.
According to Perlowin, the primary cause of hermaphroditic plants, commonly known as 'hermies,' is stress. These stressors can manifest in various forms, such as insufficient or excessive water, inadequate nutrients, excessive heat, and disruptions to the photoperiod (light exposure), among others. Herming can occur at any stage of a plant's life, from its early growth to maturity.
When a female cannabis plant experiences stress, it responds by developing male flowers to ensure seed production before any environmental threat can harm the plant. Several factors can trigger this response, including drastic temperature changes, disease or pest infestations, the use of toxic pesticides, and physical damage from aggressive pruning.
Genetics can also play a role in herming tendencies, with some growers considering plants prone to hermaphroditism as genetically inferior. However, Perlowin points out that herming may not be entirely cultivar-specific. The same cultivars obtained from different seed companies can yield different results. Reputable breeders are more likely to carefully select seeds from genetically robust plants with desirable traits, thereby reducing the likelihood of herming issues.
In summary, hermaphroditism in cannabis is primarily caused by environmental stressors, but genetics can also influence the likelihood of this occurrence. By sourcing seeds from reputable breeders, growers can increase their chances of cultivating plants that are less prone to hermaphroditism and possess desirable characteristics.
How can growers prevent hermaphroditic plants?
The majority of cannabis growers focus on cultivating sensimilla, which refers to unpollinated female buds. Sensimilla is more potent than seeded cannabis due to higher concentrations of essential oils and psychoactive cannabinoids.
When female cannabis plants herm, developing male flowers capable of pollination, the entire crop is at risk. Fertilized female flowers stop developing, resulting in limited flower production.
To prevent herming, growers must be diligent throughout the plant's growth cycle. It starts with purchasing seeds from reputable companies or trusted breeders with knowledge of cannabis genetics. Regular monitoring and minimizing potential stressors are crucial. Daily inspections are essential to spot any abnormal growth.
Bruce Perlowin advises closely watching the plants to detect hermaphrodites or pollen, which can adversely affect the entire cultivation. Swiftly remove any male flowers that appear. If there are only a few, they can be removed, but close monitoring is necessary. For plants with many male flowers, it's better to eliminate the entire plant.
The removal process involves using a large plastic bag to cover the entire plant, sealing it, cutting the plant at ground level, and then removing it from the property without shaking it to prevent pollen dissemination.
How can you tell a male plant from a female plant?
To the untrained eye, all cannabis seeds appear alike. However, as the plant nears the flowering stage, its gender becomes more evident.
In his book "Marijuana Botany An Advanced Study: The Propagation and Breeding of Distinctive Cannabis," author Robert Connell Clarke provides clear instructions for distinguishing between male and female plants. The gender of a cannabis plant can be identified at the nodes along the main stem.
Male plants are most easily recognized when they begin to flower. Initially, their flowers take the form of a curved claw, which later transforms into a flower bud with five radial segments. As they develop, pollen sacs emerge, resembling small bunches of grapes. Eventually, the pollen sacs' sepals open to release pollen.
Perlowin explains, "When you see a pollen sac, you will know that a female plant is turning male. Often, you can detect this before the pollen sacs become problematic. It's essential to inspect the plant from the bottom to the top, not just when the pollen sacs are at the top."
Furthermore, male plants tend to grow taller than females as they mature, featuring thicker stems and fewer leaves.
Can you turn a male plant female?
The sex of a plant is determined by its genetics even before germination starts. It's not possible to change a male plant into a female or vice versa due to this genetic encoding. However, there are techniques to encourage male plants to exhibit female characteristics. These methods involve using chemicals like ethylene to trigger a hormonal response in the plant.
By elevating female hormones in male cannabis plants, the technique can prompt female flowering development. It is more effective when applied to male plants before they form mature flowers. Nonetheless, identifying true male plants can be challenging as many male marijuana plants are hermaphroditic.
Can you clone a female from a male?
It's not possible to clone a true female cannabis plant from a male plant. Cloning is a method used by breeders to replicate genetically identical copies of healthy female plants, providing certainty in the cultivated cannabis.
Growers seeking to grow female cannabis plants from seed can simplify the process with feminized seeds. These seeds are created by inducing a female plant to hermaphroditic, and then using its pollen to fertilize another female plant. The resulting seeds contain only female chromosomes, ensuring no true males will develop from them.