how to make female seeds

How To Make Feminized Cannabis Seeds Like The Pros

Growing from feminized cannabis seeds is a space and resource-efficient way of getting all girls, all the time. Find out how to create your own feminized cannabis with Royal Queen Seeds.



Growing cannabis is all about resinous flowers, trichomes, and rich cannabinoid profiles. These splendid characteristics can only be found on the female flowers. Having gardens full of robust, un-pollinated sinsemilla females means jars full of mind and body-friendly, crusty nuggets.

The only bummer, unless you grow from clones, is that cannabis is wired to produce about 50% male seeds and 50% females. It is just the nature of the beast.

Wouldn’t it be sweet if it was possible to grow all females from seed, every plant, every time?

Well, that is where the feminizing technique comes into play: two methods of manipulating the cannabis plant to produce only females from seed, every-time. To be truthful, it isn’t every single time. But 99% of the time is a pretty good number, and could be considered entirely male risk-free.

The general practice behind feminization is that female plants are forced to produce pollen, which is in turn used to pollinate other female plants. The outcome? Resulting seeds will be feminized, with no risk of further pollination.


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.


“Applications that reduce the ethylene level in tissues or antagonise the action of ethylene causes the formation of male flowers instead of female ones” — Paraphrase, Byers et al., 1972.

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.

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.


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 can’t be removed by normal filtering. Colloidal silver is available commercially, or you can make your own if you want to totally geek out (see how-to section at the end). 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.

Be sure the strength is at least 15ppm, preferably 30ppm. Less than 15ppm produces male sacs with little viable pollen.

To begin with, select a plant that has the characteristics you want to preserved. Feminizing clones is the usual practice as the growth, flowering, and resin characteristics from the mother are already known. There is no need for any vegetation time once a clone is well-rooted. Simply pot the clone into a small pot, give it a day or two to recover, and begin a 12-12 light cycle right away. A pollen-producing plant only needs to be small as cannabis produces copious amounts of pollen.

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.

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.

Spray the plants to be feminized with colloidal silver every day, and three times a day if you can manage. Soak them well. Do this for two weeks, then leave the plants to grow as normal. Some growers report getting results after spraying for only 5–10 days.

When sexing begins, male pollen sacs will develop instead of female calyxes and pistils. Male plants mature much faster than females, and viable pollen can be expected within 3–4 weeks once the plant has been sexed. Some growers will spray until the plant shows sexual growth, just to be sure the method has worked. Make sure these plants are well-isolated from any flowering females. A burst pod can release millions of pollen spores, and it only takes one spore per hair to create a seed.


Once the plants have been sprayed with colloidal silver and the pollen is collected, they are write-offs—86 them and don’t smoke them. Giving them a thorough rinse will not work. The colloidal silver is a systemic treatment absorbed into the plant through the foliage and not a topical application. Be safe and bin them.


Sinsemilla is an unnatural state for cannabis. Without human intervention, it would be rare to find an unpollinated female in the wild—unless it was sterile. When sinsemilla plants are left to go beyond their desirable maturation stage by a number of weeks, the plant, through whatever amazing processes evolution has bestowed, knows it has not been pollinated. As a last ditch effort at propagation, it will produce male pollen sacs in an effort to self-pollinate.

This is not the result of genetic or stress-induced hermaphroditism. They are genuine XX chromosome male bananas. With all the genetic information from the female and no Y chromosome, using rodelized pollen creates female-only seeds, although as with colloidal silver, an occasional male may appear.


There are a number of harvesting methods employed to catch pollen.

  • 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.


Treat feminized seeds as you would any other seed from germination to veg, and veg through flower. Observation is where it’s at now, you want the best plants for your garden. Ideally, setting up a separate vegetation/flower space where a number of plants can be grown lets your standard grow space continue with uninterrupted production.

Plants bred using feminization are homozygous. This can have two effects that can’t be assessed until the seeds are grown. Homozygosity will increase the dominant or recessive traits of the parent in the progeny, so features you don’t want and do want can be amplified. Genetics is a weird, weird thing.

Just as with standard male to female crossings (which is a heterozygous process), a number of plants will need to be grown and the best selected for mother plants and future breeding. With enough room, hundreds if not thousands of new plants can be grown in order to select the best of the best phenotypes.


With a bit of aforethought, it is possible to set up an efficient feminization breeding programme—and have female seeds from your favourite phenos on hand all the time. You never know, you might discover the next big thing!


The easiest and relatively inexpensive way—considering how much money is potentially saved by not growing resource and time-consuming males—is to buy a colloidal silver generator, which is the no-fuss plug and play option. Or, make your own, which is quite straightforward and doesn’t require any special skill.

Colloidal silver is formed by passing a current from a pure silver electrode through distilled water. This simple electrolysis is all there is to it. Although distilled water does not conduct electricity very well due to its lack of mineral content, enough is passed through to create micro silver particles and silver ionisation. Sounds technical, but it really isn’t.

Feminized cannabis seeds only produce female plants, which has a number of advantages. Find out how to do it with Royal Queen Seeds.

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.

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 (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!

Curious how to make feminized seeds? Making feminized seeds is a difficult process but it can be done! How? Check it out!