Guide on How to Make Feminized Seeds

Guide on How to Make Feminized Seeds

Feminized seeds first entered the cannabis market about 15 years ago. Even if some seed banks were initially reluctant. In the meantime, virtually all of them now sell feminized seeds in their catalogue.

Making feminized seeds isn't easy at all. We therefore recommend buying high quality feminized marijuana seeds from a reliable source. Yet, if you are dare a devil you can try to make them yourself.

Curious how to feminize seeds? With this guide we tell you exactly how to make feminized seeds at home. 

The background of feminized seeds

Most growers use only feminized seeds and some have never even seen a male plant in their lives. Many young cultivators cannot even remember a time when only regular cannabis seeds were available.

Growing weed from seeds was only possible by starting with twice as many plants. To obtain, for example, 10 female plants, it was necessary to plant 20 regular seeds. It was, of course, impossible to predict exactly the number of female plants and there were often good or bad surprises. It was easily possible to end up with no female plants out of a pack of ten!

Cuttings / clones

For growers who had the opportunity, the best solution for growing only females was to obtain cuttings of female plants or to take clones themselves from selected mother plants. However, not all growers can afford to produce their own cuttings. You must have an indoor growing space with specific lighting and the possibility of growing over a long period after selecting one or more mother plants. It is not always easy to make your own cuttings and growers need to know a number of techniques. These are the reasons that led to seed banks producing feminized seeds.

Related article: how to clone a weed plant

Outdoor growers, in particular, were interested in feminized seeds. Indeed, outdoor growers must keep their plants growing for several months before their sex is revealed, usually during August. In guerilla crops, plants are sometimes difficult to access and it is not always easy to remove the males before pollination. With a culture based on regular seeds, the outdoor grower can end up with a majority of male plants, which can compromise his entire season.

The arrival of feminized seeds, followed by autoflowering feminized seeds, has boosted the sector, making cannabis cultivation easy to access. No more need to recognize males and females and more risk of ending up only with males in its growing space or facing unwanted pollination. Plus you can choose to breed from plants with characteristics that you love.

How to feminize seeds?

As explained above, making your own feminized seeds is pretty difficult but it can be done by changing the sex of the plant which is called "reversion" for which you need a hermaphrodite. The pollen from this plant will fertilize a group of female clones and obtain feminized seeds without having the hermaphrodite traits of a true hermaphrodite plant. We, therefore, speak of "feminization" of seeds but it is above all a question of "masculinizing" a female plant which will act as a reproductive male. Products like GA3 or silver nitrate, therefore, allow the development of male organs and others like phytohormone auxin or ethylene promote the development of female organs.

Products and methods to feminize seeds

Making your own feminized seeds can be done with different methods. The most common methods are: 

  1. Rodhelization
  2. Gibberellic acid
  3. Silver nitrate
  4. STS
  5. Colloidal silver

1. Rodhelization (not recommended)

This is the easiest method to get feminized seeds naturally without any products, but there are many disadvantages to this method. The goal is to stress a female cannabis plant to make it hermaphrodite. This happens from time to time in the wild, usually after the plant is subject to stress such as a lack of water. It naturally produces male pollen flowers and ends up self-pollinating. Changing the photoperiod several times is one of the techniques used to stress the plant and obtain male flowers. Keeping the plant in its growing space at the end of the life cycle, well after maturation, may favour the appearance of flowers. This technique is a bit random and does not always allow good results to be obtained. In fact, you are highly likely to end up with a high proportion of hermie (hermaphrodite) plants in the mix.

2. Gibberellic acid

Gibberellins are a family of phytohormones. Their active compound is called gibberellic acid. Gibberellins are called G or GA and followed by a number from 1 to 110, GA3 being the best known. Long used for growing plants, including cannabis, gibberellin was first identified in 1926 by phytopathologist Eiichi Kurosawa. The chemical structure of gibberellic acid was determined in 1955.

Present in its natural state in plants, it is cultivated in the laboratory in the form of a mushroom and marketed in the form of a GA3 spray. In the cannabis sector, it has several uses. It promotes germination, lifting the dormancy of some old seeds or those that have difficulty germinating. Some use it to obtain larger female flowers, provided that they do not exceed certain dosages. But GA3 is mainly used to reverse female plants. The spray is deposited on cotton which is applied directly to the female flowers of the selected plant, at the beginning or in the middle of flowering. Become a hermaphrodite plant, it will be able to pollinate a group of clones which will then produce only feminized seeds.

Gibberellic acid has long been used to obtain feminized seeds, but most professional seed banks now use silver nitrate, which is considered more effective.

3. Silver nitrate

Silver nitrate is an inorganic compound which has different uses, especially in the health field thanks to its antiseptic properties. It is used for the production of feminized seeds most of the time in combination with sodium thiosulfate to form the STS (Silver Thiosulfate).

4. STS

STS is a mixture of silver nitrate and sodium thiosulfate. This product is mostly used for the production of feminized cannabis seeds. It is possible to buy it ready-made or to prepare it yourself.

5. Colloidal silver

Colloidal silver also allows the reversion of female cannabis plants. It is easily found in online stores and it is possible to prepare it yourself. All you need is colloidal silver with a 9V battery, 2 alligator clips and two silver coins - and a YouTube tutorial to tell you what to do!

Making feminized seeds (step by step)

Once you have colloidal silver or the substance of your choice, the method of preparing the plants is pretty straightforward.

  1. Spray the bud areas of your chosen female plant each day during the initial month of the flowering stage.
  2. As soon as you switch to a 12/12 light schedule, select the bud sites of your selected female plant, and give them a good soaking each day with the colloidal silver, STS or gibberellic acid.
  3. As the treated flowers start to develop, you will notice them forming into male pollen sacs. The bud sites that you don't treat will develop normally into female flowers but don't be tempted to harvest them unless you are completely confident that they haven't been exposed to the colloidal silver during the feminization process as this can be toxic to smoke.
  4. The male pollen sacs can be harvested when they become swollen and begin to open up -like a ripe seed pod. Don't harvest until you are sure they are ready and keep up the spraying routine or you could risk ending up with empty sac! You can collect the pollen sacs by picking the seed heads and leaving them to dry for a week. At that point, they can be placed in a Ziploc bag and shaken to safely gather all the pollen. The pollen can then be used to fertilise another female plant; ideally, one that is two to three weeks into the flowering phase. You will need a soft-haired paintbrush to apply the pollen carefully to the chosen female plant. Just gently dab the pollen directly onto the bud sites. You are mimicking the actions of a bee or another pollinating insect!
  5. Six weeks later you will be ready to harvest your very own feminized seeds. You can either germinate them straight away or store them in a cool, dry and dark place for up to two years - or possibly even longer although we doubt that you will be able to wait that long! Be a professional grower and label them with details of the strain and the date.

Final thoughts

Some growers are reluctant to try and grow feminized seeds, saying that it doesn't feel right and is interfering with nature. However, it is a process that occurs naturally - lobelias, for example, only flowers with hermaphrodite and female plants. Male plants encourage genetic diversity - and the leaves of male plants can be used to make excellent hashish so feminization is not a road that is essential to explore. However, there is no strong scientific reason not to only use feminized seeds - at least for a couple of generations. Just make sure you do it the right way so as not to end up with lots of hermaphrodite plants.

Don't want to take that risk? Buy feminized marijuana seeds at Weedseedsexpress!