To determine the sex of your cannabis plants, you will have to wait until the pre-flowering stage when plants begin to put their energy into reproduction. Female cannabis plants show their gender signs later than males. At the location where they will soon grow their buds (the nodes between the stalk and the stem), females will show wispy white hairs.
There is a good reason why most growers keep male plants away from their ladies: Pollination from males causes the females to develop seeds. As a result, females focus their energy on seed production, rather than on growing you some fine-quality bud. This seedy and unfortunate final product can be avoided by implementing a few basic techniques.
Obviously, no one wants to smoke seedy weed. When you grow cannabis and learn how to identify male plants and signs of pollination, you can remove these plants to save your remaining females. Likewise, recognising a pollinated female early allows you to start again before it’s too late, rather than finishing a grow that will only result in a poor-quality harvest.
WHAT TO DO WHEN YOUR FEMALES GET POLLINATED?
Spotting male cannabis plants and pollinated females early can save you from investing further time and effort into an entire growing season that will be for naught. Most of the time, the best course of action is to get rid of the males along with your pollinated ladies and just start a new grow.
Pollination requires the presence of males or intersex (hermaphrodite) plants, which are females that will also produce pollen. The first thing you want to do to keep the risk of pollination low is to remove as many males or “hermies” as as you can. Especially during the first three weeks of flowering, it’s important to frequently check for possible male specimens in your garden.
The typical cannabis grower normally doesn’t have a reason to keep males, and will want to get rid of them as soon as they are spotted. Cannabis breeders, on the other hand, may want to keep males along with their crop of female plants. In such cases, the breeder will normally separate the sexes to avoid any accidental pollination. They may grow females in one tent and males in another. When grown outdoors, such as in a garden, the males are often kept in the most remote corner of their growing area, as far from the females as possible. Even then, because of the wind carrying around the pollen, there is always some risk of accidental pollination.
Another indication of pollination can be the colour of her pistil hairs. When a female has been pollinated, the previously white hairs will soon shrivel and become darker.
Growers identify plant sex by identifying pre-flowers, which are small structures that form at the nodes during late vegetation.
Cannabis belongs to a minority of species that are dioecious in nature, meaning they produce separate male and female plants. Specifically, it should be noted that only 7% of all angiosperms (flowering plant species) possess this rare and interesting trait.
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.
IDENTIFYING FEMALE CANNABIS PLANTS
Male and female plants look identical during the seedling and vegetative phases. But, as they begin to transition into the flowering phase, plants finally begin to reveal their sex. During this time, females produce resinous buds loaded with cannabinoids, and males form sacs filled with pollen.
These protruding structures are designed to capture pollen, which leads to fertilisation. They stick out away from the flower to capture pollen from the air, and to await being brushed up against by pollen-covered insects.
Within a matter of weeks, these small pre-flowers swell into dense nuggets and begin churning out cannabinoid and terpene-rich resin. Since you the removed males and prevented pollination, your flowers will continuously produce resin until the end of the growing cycle.
To avoid this issue, try to maintain a stable environment in your grow room. Use a thermo-hygrometer to monitor temperature and humidity, keep your light schedule strict, and ensure your plants get all the nutrients they require.
Other stressors that may incite female cannabis plants to become hermaphroditic include disruptions to the photoperiod, dramatic shifts in temperature, disease or pest infestations, the use of toxic pesticides, and physical damage from vigorous pruning.
“With hemp and cannabis, you h ave to walk your fields or monitor your plants every single day to ensure that there are no hermaphrodites or pollen on the plants, as it will affect the rest of your grow,” states Perlowin. “It is surprising how fast something can go wrong so it is important to watch closely. If you don’t find these plants, you could be jeopardizing not only your crops, but also those of other growers .”
Perlowin advises that growers who wish to prevent female cannabis plants from herming must be diligent throughout the plant’s grow cycle. For starters, purchase seeds from a reputable company or trustworthy breeder that understands cannabis genetics. While potential environmental stressors must be monitored and minimized, growers should also examine their plants every day for any unusual growth.
The sex of a plant is determined by its genetics before germination even begins. With the sex genetically encoded, there is no way to make a male plant female, or a female plant male. There are techniques that can be used, however, to encourage a male plant to display female characteristics. These techniques require the use of chemicals, such as ethylene , to prompt a hormonal response from the plant.
When female plants herm, or develop male flowers capable of disseminating pollen, the entire crop is at risk of pollination. Female flowers that have been fertilized by pollen will halt their development to produce seeds, limiting flower production.