There are a few techniques that can produce reliably feminized seeds. One classic method is stressing out a healthy female plant by interrupting its light cycle during flowering. While that works to an extent, the more common and controlled method is to spray down female plants with a collodial silver or silver thiosulphate solution. This method makes it possible to control the sex of a plant without any genetic tinkering or modification.
Growing cannabis in your home is legal in an increasing number of states and provinces throughout the United States and Canada. To make starting a home garden easy, growers can start with feminized seeds for many popular strains from providers like Kannabia.
Growers can avoid spending weeks nurturing plants with only a 50% chance of expressing as female and maximize the space and plant count in their gardens by using feminized seeds from suppliers like Kannabia. These specially-treated seeds increase the probability of producing a female plant to 99%.
How Are Cannabis Seeds Feminized?
Both substances are a blend of water and fine silver particles, and they work in largely the same fashion. The silver solution impedes the production of ethylene, a hormone involved in flowering. The result is a female plant, but one that produces male flowers with pollen sacs. Since those pollen sacs develop on a plant with only female genetics, female genetics are all they carry. When those flowers pollinate another female plant (one untreated by silver solutions), the resulting seeds are nearly certain to be female.
Once those plants are old enough, growers have to go to the trouble of actually determining their sex, monitoring each individual plant to ensure any males are removed before they can pollinate their female counterparts.
This is why many North American growers are turning to feminized seeds—cannabis seeds that carry only female genetics, and can be relied on to produce only female plants. By creatively applying technologies to seed feminization, modern breeders like Kannabia can ensure female genetics in seeds with a nearly 100% success rate.
Traditionally, the solution to this has been an inelegant one, with many cultivators planting at least twice as many seeds as they hope to harvest with the assumption that about half of them will be useless. However big a harvest you’re looking for, using regular seeds means you’ll have to plant twice that many seeds.
Colloidal silver is by far the easiest to source or make. It is non-toxic, non-caustic, and can be bought from a pharmacy or easily online. The other solutions can be dangerous, difficult to get a hold of, and expensive—except gibberellic acid, which can be found in nurseries, but is not as effective as colloidal silver. But if you want to watch some freaky plant growth just for the fun of it, give gibberellic acid a try. It is a growth stimulant and makes plants stretch and stretch.
Wouldn’t it be sweet if it was possible to grow all females from seed, every plant, every time?
TECHNIQUE 1: COLLOIDAL SILVER
Hint: Make two clones once a plant has been selected, one to be feminized and one to be left for pollination. This way, a separate breeding space is created and accidental seeding of other plants, or an accidental sneeze pollinating a whole grow cupboard, is avoided.
There are a number of solutions that can be sprayed on female plants to create male pollen sacs: benzothiadiazole, gibberellic acid, silver thiosulphate, silver nitrate, and colloidal silver.
Plants can be induced to grow male sex organs as late as four weeks into flowering. Though spraying one week prior to the light changeover is recommended for clones. If a plant grown from seed is being used, wait until the plant has sexed before spraying so you can be sure it is female.
4.) Pollinate Another Female Plant – At this point, take the feminized pollen you’ve collected and use it to pollinate a female plant that has been flowering for about 2-3 weeks (full detailed instructions with a video on how to do this below). Although it’s possible to pollinate the same plant as the original, it’s not recommended in part because the timing doesn’t match up (attempting to pollinate buds too late in the flowering stage leads to reduced seed production). It’s best to pollinate a different female plant that you started budding a few weeks after the original. This increases the number of seeds produced as well as gives the new female plant enough time to develop them to maturity. It also increases genetic diversity compared to self-pollination.
Growers can force a female plant to make pollen sacs, and the “feminized” pollen produced can be used to fertilize another female plant
Besides not having to worry about male plants in the next generation, the main advantage of doing this is you have a much better idea what you’re working with when it comes to producing the type of buds you’re looking for. When you’re growing a male plant, it has several genes it will pass to its offspring that has to do with how buds develop, but since it’s a male plant those genes aren’t expressed and it’s hard to figure out what they are.
To those who say this type of reproduction just doesn’t seem right, the evolutionary strategy of plants using only female and hermaphrodite plants to breed is actually pretty common and is known as gynodioecy. One example of a plant that only reproduces this way is a flower found in Canada and the US called Lobelia siphilitica, also known as the Great Lobelia. Obviously this reproduction method isn’t exactly the same as artificial feminization since the pollen production is caused naturally instead of induced chemically, but examples of gynodioecy show that a female flower-based breeding population can exist in the wild even when no plants are purely male.
6 Weeks to Harvest Seeds