Cannabis is unique in that it can have both male and female parts on the same plant while also being able to have male and female plants.
In this sense, they are both monoecious and dioecious. The female plant will exhibit characteristics that mark it as such, specifically found within the pistil, or female sex organ of the plant.
You’ll notice that as your cannabis plant goes into the flowering stage that little white hairs will start coming out of the bud that will eventually turn red and then brown as the plant passes its harvest date.
Those little red hairs are called the stigma and they are part of the pistil. Their function is to capture pollen from a male plant that will fertilize the female flower and produce seeds. It is an indication of plant health and when to harvest your cannabis crop.
It is important to be diligent when watching the stigmas for when to harvest your plant. There are other reasons as to why they might be turning red that don’t involve harvesting.
What the color of your stigmas is telling you
When your cannabis reaches sexual maturity (usually 3-6 weeks after germination) the female plants will start to develop little white hairs coming out of the preflowers.
Male plants will generally show their pre-flowers before the females and at the first sign of little green hairs, it is time to remove the male plants before they ruin your crop.
These white hairs on the female plant are called pistils and within those pistils are the pollen harvesting stigmas, which are what change color.
Generally, when the little stigmas start to turn red it is a sign that harvesting your cannabis plant is near. This is when the trichomes will start to go from clear to cloudy and is what growers look for when harvesting.
If you wait too long and the pistils turn a dark, ruddy, brown color it means that the trichomes have started to break down and CBN is being formed. This doesn’t really affect the high as much, but the quality of the bud will be diminished.
Red stigmas are a sign to start watching your trichomes for that optimal harvest of 60% cloudy and 40% clear.
There is, however, another reason that your pistils could turn red and if it happens before your expected harvest time, could mean that something is wrong with your plant.
Overwatering is one such cause of your stigmas turning red and then dark as the roots are suffocating and can’t provide any nutrition to your growing flowers.
Using a foliar spray of pesticide on your cannabis plant can also cause these hairs to turn red prematurely.
This is due to the chemical being too strong or the lights burning the pistils because they were left wet under the light. Usually, this is accompanied by other symptoms such as light bleaching or flower disfigurement.
Pay attention to your cannabis plant’s pistils
Cannabis does an excellent job at telling you what’s going on with it at any point in the growing cycle.
Using your plant’s pistils and stigmas is a great way to tell whether or not to start investigating when to harvest your plant.
Alternatively, using them to identify issues with your plant is another way to understand how they function.