In the pre-flowering phase, the main giveaway of a female plant is the appearance of fine, white hairs known as stigmas protruding from tiny tear-drop shaped buds. Photo by: Gina Coleman/Weedmaps
There is no way to determine the gender of a cannabis seed unless you’ve purchased feminized seeds from a reputable grower. Feminized seeds almost exclusively produce female plants; however, you should still check your crop to ensure no rogue male plants have snuck in. Feminized seeds can also become hermaphrodite plants in times of stress, particularly if they come from dubious genetic lines.
Home cultivation represents a sure-fire way to become intimately familiar with cannabis. Many novice growers are surprised to learn that cannabis is a dioecious species, which means that it produces gendered flowers. In times of stress, cannabis can also become hermaphroditic, displaying both female and male sex organs.
Young cannabis plants first begin to demonstrate signs of gender, or pre-flowers, a month after germination while the plant is still in the vegetative stage. These pre-flowers can appear as soon as four weeks after germination. However, it can take up to six weeks before the male pre-flowers are distinguishable from the female pre-flowers. While the signs for gender can be subtle, with practice, a dedicated grower can pick them out. A magnifying glass may be helpful as pre-flowers are often challenging to distinguish with the naked eye.
Male plants don’t produce buds. The male sex organs of the cannabis plant instead produce pollen sacs that are designed to fertilize the female bud and form seeds. Seedy female buds are undesirable as they provide lower-quality cannabis. It’s essential to remove the male and hermaphroditic plants from a crop as soon as possible to protect the quality of the female buds.
If you’re growing cannabis from feminized seeds, or seeds that have been cultivated to produce only female plants, the plants should grow to be exclusively female. With non-feminized or regular seeds, approximately half the plants will turn out to be male.
Sex matters when it comes to cannabis. Female cannabis plants are prized because they grow cannabinoid-rich buds. Male cannabis plants, in contrast, have less THC content than females. Though some growers do choose to keep male plants for breeding purposes in order to introduce greater genetic diversity into their crops.
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.
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.
WHAT TO DO WHEN YOUR FEMALES GET POLLINATED?
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.
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.
Flowering plants require different humidity levels and temperatures than vegging plants. Rather than changing the temperature, humidity, and light cycle at the same time, we recommend gradually changing the temperature and humidity over two days, then letting your plants grow accustomed to these changes by leaving them in veg for just a few extra days before flipping your lights.
Most growers identify the sex of their plants in the final week of vegging or the early weeks of flowering. Remember, males develop pollen sacs that look like small balls, and need to be culled or separated from your females if you want to avoid them getting pollinated.
• TRIM EXCESS FOLIAGE
To find out when it’s time to harvest your plant, you can use a jeweller’s loupe or a small microscope to regularly check your plants’ trichomes. You can observe whether the trichomes turn from clear to a milky white colour. If many of the trichomes you see are still clear and transparent, it means it’s still too early for harvest. But when most of the trichomes have an amber colour and an opaque clarity, this means that the THC content of the buds is at its maximum and the plant is ready for harvest.
This phase of flowering where your plant is starting to spend increasingly more energy on growing flowers is particularly critical. Make sure that the nutrients you give are appropriate and check the labels for the recommended dosages.
At week 4 of the flowering stage, your cannabis plants will likely have stopped growing altogether and are now spending all their energy on growing buds. There will still be white hairs sticking out from the buds, but the buds themselves will become bigger and fatter with each day. With more and larger buds growing, your plants will now produce more trichomes, making the odour a lot more noticeable at this stage.
What happens during flowering and at what exact time can somewhat vary depending on the particular strain you are growing. So don’t expect your plants to follow this schedule to the T; see it more as a general guideline that you can go by. Let us look at the flowering phase of cannabis week by week.