Male pre-flowers look like tiny green eggs or “balls”. These young pollen sacs will look smooth and won’t possess any fine hairs, or any distinct point. Later into the flowering stage, pollen sacs begin to form larger and denser clusters. They’ll become easy to identify with the naked eye by this point. However, pollen sacs usually begin to disperse their contents around 2–3 weeks after forming. Be sure to remove them from your space with haste if you don’t plan on crossing your plants.
Even if you have all of these bases covered, plants can still pollinate themselves due to poor genetics. Plants with a bad genetic history and too much genetic variation are prone to becoming hermaphrodites. For this reason, it’s important to shop with reputable companies that offer high-quality seeds with stable genetics.
IDENTIFYING FEMALE CANNABIS PLANTS
Female pre-flowers also develop at the nodes. You can distinguish them based on one obvious visual characteristic: hairs. Female pre-flowers feature tear-drop shaped calyxes with small hairs protruding from the tip. These small hairs, known as pistils, are the sex organs of female cannabis flowers.
Cannabis growers and breeders use this trait to their advantage, since it allows them to separate male and female plants. This enables them to prevent the flowers from becoming fertilised and going to seed, which results in better quality flowers, known as sinsemilla.
During the early flowering stage, take a stroll around your grow room or garden with a magnifying glass or jeweller’s loupe. Inspect a few nodes on each plant to see how far along into the flowering process they are. At this stage, you won’t see any obvious flowers or pollen sacs. Instead, you’re looking for young pre-flowers. Although these tiny structures look similar, they have distinct features that allow growers to tell them apart.
The former features distinctly male and female reproductive organs. Upon close inspection, you’ll notice pollen sacs occupying some nodes, and female flowers residing at others. When the pollen sacs rupture, the pollen will displace into the flowers, and the plant will effectively breed with itself. From there, it’ll go to seed and produce the subsequent generation.
Males are important in the breeding process, but that is generally best left to expert breeders. When pollinating females, males provide half of the genetic makeup inherited by seeds.
The main stem, or stalk, of a cannabis plant grows straight up from the root system and supports all lateral branches. The stem gives a plant structure and stability.
Growers can ensure the sex of their plants by growing clones or the genetically identical clippings from a parent strain. Feminized seeds are also made available through a special breeding process.
How to determine the sex of a marijuana plant
The space between nodes is called “internodal spacing” and will give you a sense of whether a plant will grow tall or short.
A node is a point at which a branch grows off of the main stem, or one branch from another branch. Fan leaves and buds can grow on some nodes, but not necessarily all.
Female cannabis plants receive pollen from males to produce seeds, which will carry on the genetics of both plants to the next generation.
Examine the nodes of the plant and look for either the early growth of small sacs on a male, or two bracts on a female, which will eventually produce the hair-like stigma.