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How to Feminize Seeds

By Last updated on April 3, 2023April 3rd, 2023No Comments

Growing cannabis is all about resinous flowers, trichomes, and rich cannabinoid profiles. These splendid characteristics can only be found in the female flowers. Breeders and growers developed feminized cannabis seeds for this very reason.

In many ways, feminized seeds can be a good option for new growers, as it eliminates some guesswork and reduces the pressure to quickly and accurately identify and eradicate unwanted male plants. However, there are no guarantees and new growers should still do their homework and know how to spot a male cannabis plant.

What are feminized seeds?

When it comes to cannabis plants, females are the only sex that can produce buds. Feminized cannabis seeds grow plants that are exclusively female and can almost guarantee that every plant that sprouts from its shells will flower.

Normally, a male cannabis plant will pollinate a female plant, and that is how seeds are produced. The resulting harvest of regular cannabis seeds will contain about half male and half female seeds. For the grower, this is inefficient. Roughly half of an entire grow can be tossed at harvest time if the seeds are not feminized.

Are feminized seeds guaranteed to be female?

While feminized seeds generally grow only female plants, it is not a 100 percent guarantee. Every once in a while, a feminized seed will still grow up to become a male plant. For this reason, it is a good idea to keep a close eye on your plants as they mature.

If you ever see pollen sacs starting to form, you have got a male plant and you should eliminate it before it accidentally pollinates and ruins your female plants.

How are cannabis seeds feminized?

Feminized cannabis seeds are created through a process of genetic manipulation. Essentially, the idea is to induce female plants to make pollen. Normally, only male plants produce pollen, but if you can somehow make a female plant produce pollen, then what you have got is pollen containing only female chromosomes. Here are the ways to make this happen:

Colloidal silver

Colloidal silver is a distilled water-based solution in which microscopic particles of silver are suspended. The nature of colloids means the particles will never settle out and cannot be removed by normal filtering. Colloidal silver is available commercially, or you can make your own if you feel ambitious but it is rather difficult. It has numerous uses as an alternative medicine. For example, it is used to soothe burns, as an antiseptic and digestion stimulant in people, and as a fungal control in horticulture.

Spray a female plant with colloidal silver while it grows and transitions into the flowering phase. Remove the plant from the grow area before you spray to avoid getting the colloidal silver on the other plants. This chemical promotes the growth of pollen sacs, and because this pollen comes from a female plant it carries female chromosomes.

After the plant starts producing pollen, use it to pollinate the flowers on a regular female cannabis plant. These pollinated flowers will produce feminized seeds.

Once the plants have been sprayed with colloidal silver and the pollen is collected, dispose of them and do not smoke them. Giving them a thorough rinse will not work. Colloidal silver is a systemic treatment absorbed into the plant through the foliage and not a topical application.

Silver thiosulfate solution

Silver thiosulfate solution, or STS for short, is a chemical mix that is used for producing feminized pollen. STS is the most reliable and commonly used method for creating feminized seeds. This chemical suppresses the production of ethylene, which is necessary to the flowering process.

By feeding your female plant silver thiosulfate solution, you encourage the plant to produce pollen, which can be used to pollinate other female plants and produce feminized cannabis seeds. Spray the STS on the leaves of your cannabis plants until they are fully covered in the mixture and dripping.

It is recommended to remove the plant that you intend to spray from the grow area to avoid spraying the STS on the other plants. It is best to begin spraying 4 to 5 days after flipping your lights to a 12 hours on, 12 hours off schedule, while they are turned off. This allows you to spray the plants without the fear of causing damage to them. Re-spray the plants using the same process after 10 days.

Male flowers with pollen sacs will appear on the sprayed plants, and this pollen can be used on other plants which will produce seeds with all-female genes. One can use the pollinated plants and make extracts from their resin because the number of seeds that they produce is going to make them useless. The sprayed plants will eventually have to get discarded as they are going to become too toxic to be used.

When making feminized seeds using STS, one can combine different strains, thus resulting in a feminized hybrid that one has made himself, which is very satisfying.


The third main method is known as rodelization. This is an all-natural technique, although it does not produce as consistent outcomes as the colloidal silver or silver thiosulfate methods. This process involves the natural response of the females when they are under stress. When feeling stress or are reaching the end of their lives after not having been fertilized, females will actually start to grow pollen sacs without any male fertilization.

This is a simple evolutionary response that allows plants that were never fertilized to continue their “bloodline.” Because the resulting seeds come from exclusively female genetics, the likelihood of them being female seeds is much higher than usual.

Rodelization purposefully encourages this process to come about, exponentially increasing the odds of the seeds being female. Although it can be tricky, it is generally a simpler task than using the other methods. Because it is a totally natural process, you will need to depend on your plant to act accordingly.

The lack of reliability is the main disadvantage of this method. Even if everything goes right, the seeds might somehow not be feminized. Because of this risk, you need to think about whether or not this is the method for you. Many growers choose this method because it is completely natural, and perhaps they are already organic growers. Some strains will work better than others for this method as well.