how to feminize cannabis seeds

How are feminized seeds made?

Image of a purple seed emerging from many others in black and white

Feminized seeds were a revolution when they came on the market more than 15 years ago. Nowadays they represent more than 75% of the worldwide sales of marijuana seeds, and this is no coincidence, as during this time they have proven to be just as good, or even better, than regular seeds. In this article we will see different ways to create 100% feminine seeds, are you in?👉

🔥 Is it easy to create feminized marijuana seeds?

If you have ever wondered how to feminize a cannabis seed and you imagined it was a difficult task I’ll tell you it wasn’t, creating a good regular variety can be as complicated as producing female cannabis seeds, because the greatest difficulty is in finding parents who transmit their best qualities to the offspring.

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.✍

Image where you can see the thin pollen produced by a reversed plant falling on female cannabis flowers*

🎯 How to make feminized seeds with STS step by step

  1. Prepare STS (Silver Thiosulphate), mixing silver nitrate with sodium sulphate.
  2. Spray the STS on the plants that we want to reverse their sex, these will act as “male” in pollination.
  3. Change the photoperiod to flowering and repeat the spray application of STS one week later and again 15 days after the first time.
  4. After the third application change the photoperiod of the receptors that will act as female during pollination, this will be the last application of STS, after the second one we already inhibit the production of ethylene, which causes the plant to flower as male instead of female.
  5. About 25 days after putting the receptors in bloom they will begin to be at their best to be pollinated, depending on the variety, this will happen at the time when the reversed ones start to release pollen.
  6. Pollinate for 2 or 3 weeks if you want to get a lot of seeds, if you want to get few and take advantage of the rest of buds to consume you can do a located pollination on a single branch.
  7. After the last pollen intake by the females it is time to ripen the feminized seeds, it is very simple, we only have to feed the plants for 30 days more as when we cultivate to produce flowers.

Requirements for parental selection

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.

When we choose the varieties we want to cross we have to look at the desirable qualities, such as taste, production, effect, speed, and so on. But it must be clear that these features are only useful if they are transmitted to the progeny, a good phenotype is only a good phenotype if its qualities are not transferred to its descendants. On the other hand, if it transmits those qualities, it can also be considered a good breeding tool.

Photograph of a hermaphrodite marijuana bud where you can see both male and female flowers*

🧐 Are there other ways to produce feminized cannabis seeds?

Yes, there are, although not as effective and reliable as with STS, so we do not recommend them. But if you want to know other ways to make 100% feminine seeds of your favorite weed I’ll tell you. First of all you have to understand that all techniques are based on stressing a female plant to revert its sex to male, so it can produce flowers with which it can pollinate another female.

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 most common technique used to cause stress to female plants was known as “Light Poisoningor light stress. It’s easy, you just have to use irregular photoperiods, or often interrupt the night cycle of female cannabis plants during flowering.

⚠️ What is Rodelization?

It is another stress process, in this case due to over-ripe, i.e. not harvesting in time or lengthening the flowering cycle of a female cannabis plant to produce male flowers. This method is not very good because of the small amount of pollen that is created, it is not worth it if you want to make many feminized seeds.

This is something they do naturally as a way of perpetuating the species. When a female guesses she’s going to die and hasn’t been pollinated, she spontaneously generates fertile male flowers to self-pollinate and continue with the lineage.

⛳ Making feminized seeds with colloidal silver

The technique for producing feminized marijuana seeds with colloidal silver is based on the same theory as the STS one. Both use silver to inhibit the production of ethylene in a female plant, and that this specimen blooms as a male and releases pollen.

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.

👌 How are feminized seeds made with gibberellic acid?

This way of producing 100% feminine seeds with gibberellic acid was published by the great Robert Connell Clarke in his magnificent book “Marijuana Botany”. With this method several applications must be done during a period of 5 or 7 days. The biggest problem with gibberellic acid technique is its instability, since a very precise dose is needed to be effective, around 100 PPM. It is also common that each variety may need a different dose, so not many people use it nowadays.

👾 Conclusions

If you want to make your own feminized seeds, I recommend you the STS method, it is the most used for some reason. You have to be careful not to inhale the gases it produces, protecting yourself with a mask, safety goggles and gloves for its manipulation, but it is the most effective technique. It is surprising to see an elite clone bloom as a male after having grown it many times as a female, I invite you to try it.

If you liked this article you can help us if you share it, that way if a friend of yours is curious about how to get feminized seeds he/she can see it here.🤪

Do you want to know the best way to produce feminized cannabis seeds? ✨ In this article we will show you ❤️ See how easy you can create your 100% feminine.

How to Feminize Seeds

The cannabis industry has evolved more in the last 15 years than it has in the last century. Society has also evolved, allowing cannabis and the idea of weed to slowly make its way into pop culture, with more and more strains available as well as accessories for smoking or consuming cannabis. Nowadays, pretty much anyone can grow cannabis in their own house with all of the necessary equipment to make their own strains. Years ago only a select few had access to such equipment. Today we’re going to show you how to feminize seeds. You won’t need many items to do so, and the ones you do need are easy enough to get.

Like most living creatures, cannabis plants need a male and a female specimen to reproduce; the male pollinates the female plant which causes seeds to grow. The resulting seeds have genes from both the mother and father plants, so it has a 50% possibility of being female or male. This is why you need to find a way to get your seeds by using just female plants, completely getting rid of male genes, which only leaves the possibility for female seeds.

How to Feminize Seeds | Tutorial

Many growers know that if you stress out cannabis plants, they can easily become hermaphoridtes (a plant with both male and female sex organs) which end up creating male flowers that create pollen which then “impregnates” the plant and others around it. The issue with stress-caused hermaphrodite plants is that most of the resulting seeds tend to be hermaphrodites too, so it’s not the best method to use and it also stresses your plants out quite a lot.

In order to turn a female plant male without stressing it out, all you need is some Silver Thiosulfate, also known as STS. If you apply STS to female plants it will modify their ethylene levels, which is the hormone in charge of determining the sex of certain plants. This causes female plants to change sex and turn into males without the disadvantage of male genes.

Silver Thiosulfate

Making your own STS only takes about 15 to 20 minutes and you’ll need two ingredients: Sodium Thiosulfate and Silver Nitrate, both of which can easily be found in any pharmacy and on our webstore. Sodium Thiosulfate is a neutral chemical salt that’s used to reduce side-effects in some cancer treatments and can easily be bought without a prescription.

You can acquire silver nitrate on our webstore, although some people prefer to extract it from other products that contain it, such as Argenpal, a product used to get rid of warts – each one of these little contains a very small amount of Silver Nitrate, so it’s probably better just to buy it directly without the need to spend more money or spend forever trying to extract the Silver Nitrate from the product itself. We stock Panreac Silver Nitrate, which may be a bit more expensive but you’re guaranteed the best quality, and it saves quite a lot of time.

How to Feminize Seeds | Making STS


You’ll need protective material such as gloves, safety glasses and a face mask; STS can be quite toxic when inhaled and it can leave large burns on the skin. Make sure you don’t use any metallic objects when making STS – everything should be plastic, as metal can alter the composition and reduce efficiency.


Do not use metal instruments or tools in this process. The first thing you’ll need to do is grab a plastic cup and pour in 20ml of distilled water. Next, depending on your chosen method, get either 7 Argenpal sticks or 0.35g silver nitrate. If working with Argenplal, dilute the tips delicately in the water (the tip is where the silver nitrate is). Grab another plastic cup and add 30ml distilled water and 1.3g of sodium thiosulfate, mixing it slowly until it’s fully dissolved. Then, mix the contents of both glasses and mix slowly again – make sure to use a plastic spoon, no metal.

The result is 50ml of pure Silver Thiosulfate, much too potent to use on your plants, so you’ll need to water it down a bit. Add your Silver Thiosulfate to 400ml of distilled water, so you’ll have around 450ml of STS. Make sure to shake quite a lot until it’s completely mixed. It’s still much too concentrated to apply straight onto your plants; take 100ml of the mixture you just made and add it to 400ml mor of distilled water. You now have 500ml of a usable STS mixture that’s ready to be used on your plants.


For maximum efficiency you’ll need to use it the same day you make it. If stored in a dark, cool space it can last up to 15 days but each day it’ll be a bit less potent. If you have it for over a week and haven’t used it we recommend making another batch if you want the best possible results.

How to Feminize Seeds | How to use STS

STS is used by spraying it on your plants leaves, making sure that it’s entirely covered and dripping. We recommend taking the plant away from your growing area before beginning the process, or the mixture might end up getting on your other plants too. You’ll need to begin applying it 4 or 5 days after flipping the lights, right before your lights go off. This allows you to spray the plant without worrying about the light burning your plants. After 10 days, you need to respray your plants, using the same process, covering the plant in the mixture and letting it soak in in the dark.

The sprayed plant will begin growing male flowers with pollen with can then be used to pollinate whichever plant you want, causing seeds to appear that have absolutely no male genes in them. You can use the pollinated plant in order to make extracts from its resin; the amount of seeds it’ll produce will render it pretty much useless in as far as smokeable flowers. The plant that you’ve applied the STS to will need to be thrown away, as it’s much too toxic to do anything with and if you consume any of it, even its resin, you could run in to some health issues.

When should you polinate your plants?

In order to efficiently pollinate select plants, we recommend having two completely separate grow rooms or areas to work in. One should be for the plants that you’re planning on switching to male in order to obtain female polen; the other should be specifically for the plants that you plan on pollinating once you’ve reverted the other ones.

When using the pollen that you’ve collected from your reverted plants, you need to make sure that the plant that you plan on using it on is fully ready for it; this can depend on the strain you’re growing. The right time to begin applying feminized pollen is actually right when your plants begin to flow real flowers.

You generally want to use the pollen as fresh as possible on a plant that is fully ready to take it on, or else it simply might not work – it’s kind of like people, in that sense. Certain things need to be just right. To harvest large amounts of high quality seeds, you’re probably better off doing a few tests in order to find out when the right moment is. You can do this by testing it out on the same strain before going big.

How to Feminize Seeds | Make your own strains

When making your own seeds you can combine your favorite strains, resulting in a plant that you’ve created yourself that is 100% feminized. When you combine two strains, you’ll get various phenotypes with varying qualities and structures. It’s important that you use regular seeds to do this, as feminized ones are much too weak and might have issues such as stress and end up becoming hermaphrodites.

In order to stabilize the genes in your resulting plants, you’ll need to select the phenotypes you like the most, meaning that you’ll need to grow quite a lot of the seeds that you get from your feminized plant. Then, take a clone from each plant and set them to flower in order to study their characteristics. Once you’re done, you’ll need to pick two mother plants, revert them and cross them with each other to get a more balanced version. This process is repeated as many times as necessary in order to create a balanced strain that has the characteristics you’re looking for.

Feminizing cannabis seeds is quite the process. You need to be able to keep perfect track and control of the timing when it comes to flowering and pollen yield if you want the best possible results. Take your time, do a few controlled tests and then you can start making large amounts of your own seeds.

Learn how to feminize seeds at home. Use silver thiosulphate to make your very own cannabis hybrids with your favorite strains for the best results.