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.
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.
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.
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.
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.
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.
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.
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.
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.
Learn about the process of pollination and why you should avoid pollination of your female plants at all costs.
One way to harvest your pollen is to gently and carefully remove all the pollen sacs. Let them dry for a week, and then put them in a resealable bag. If you shake the bag the pollen should easily spill out. You may need to cut a few open yourself.
Want to make cannabis seeds or breed your own strain but not sure how to collect pollen and pollinate effectively? It’s actually really easy!
If you triple-bag the pollen-flour mixture and stick it in the freezer (with a good nametag so you know where the pollen came from), your pollen can be stored for a year or longer. Make sure to use “freezer” bags (platsic bags specifically made for the freezer are more effective than regular plastic bags).
Pollen spilling onto a nearby leaf
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It’s time to pollinate when your plant has been in the flowering stage for about 2-3 weeks.
Example of young cannabis buds that are ready to be pollinated
When pollen sacs are cracking and opening up, you’re ready to harvest your pollen!
6 Weeks to Harvest Seeds
1.) Collect pollen when sacs crack 2.) Pollinate female 2-3 weeks into flowering stage 3.) Collect seeds ~6 weeks later. Read the article for pics and more info!