If you have already accomplished this step and your only concern is to know how to extract feminized seeds from a cannabis plant, I am going to explain it to you briefly.✍
Photograph of a hermaphrodite marijuana bud where you can see both male and female flowers*
🎯 How to make feminized seeds with STS step by step
The first feminized seeds on the market were made by naturally stressing a female to pull out male flowers with pollen. This is not a good method, since plants that revert under natural stress can easily transmit this trait to their offspring. It often happened that those feminized strains were hermaphrodites, so natural stress is not a good way to reverse cannabis females.
The females chosen to be reverted to male have to undergo a number of tests to prove that they are suitable for reversion. These tests are based on the resistance and sexual purity of the selected specimens and basically they try to induce different types of stress. Only plants that stay fully female will pass the test and then they can be considered good breeding tools.
With colloidal silver there are also several spray applications during the night cycle in some of the first days of the flowering cycle. The silver used in this method, or in the STS technique, is a heavy metal that can be toxic. It is therefore important to cover the substrate so that possible droplets from the sprayed leaves do not wet the soil.
Wouldn’t it be sweet if it was possible to grow all females from seed, every plant, every time?
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.
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.
Feminized seeds are super efficient for indoor and outdoor gardeners. Area, time, and resources aren’t being given to plants that will be thrown away two weeks after the 12-12 flip. Similarly, outdoors where a large plant can consume a lot of time and resources in upkeep prior to the autumn show of flowers, feminized plants are also a good way to reduce guerrilla crop pollinating. There’s nothing worse than bush-bashing out to a well-hidden crop only to find a rogue male or two have impregnated every female plant.
- Cover the top of the pot with plastic or card to catch pollen as it falls, or modify a plastic drink cup to shroud the plant and catch falling pollen.
- Fix a clear plastic bag, perforated at the top for air exchange, around the whole plant.
- An experienced eye will remove each flower pod prior to it bursting completely open to be sure of catching every spore.
- Pollinating a female is the easy bit. Depending on how many seeds you want to make, there are a couple of methods that can be used.
- Using a watercolour or other fine, soft brush or even a cotton bud, dip into your pollen collection and gently apply to the chosen flower. Although thousands of viable spores will be on the end of the brush, enough to pollinate a whole plant, the trichomes on the surface of the pistils will greedily glue everything you offer them. So dip into your pollen stash a few times as you dust.
- For lots of seeds, put pollen in a bag and put over a whole branch or a whole plant, shake well, and leave for twenty four hours.
- It is possible to pollinate different branches with different pollens and have a breeder plant that has 1, 2, or 15 different crosses on it.
- It is also possible to self-pollinate the plant from which the male parts were created. This won’t produce as many seeds as pollinating a separate plant because less female flowers are produced and many are nonviable because of the feminization process.
4.) Pollinate Another Female Plant
This is a relatively big topic with a lot of controversy so I wrote a whole article about it if you want to check it out!
Overview: How to Make Feminized Seeds
When your chosen mother is 2-3 weeks into the flowering stage, take a paintbrush and ‘paint’ your feminized pollen on the developing bud sites you want to pollinate. Bud sites (for both male and female plants) are located wherever you can see leaves meet a stem.
A one-hand pressure sprayer / mister is really helpful for spraying bud sites evenly and thoroughly