How To Feminize Marijuana Seeds

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Breeders feminize cannabis, and why shouldn’t you do it too? Learn how to make feminized seeds at home and grow female marijuana from a homemade source. Want to learn how to make your own feminized marijuana seeds? Checkout our ultimate guide and start growing high quality marijuana. At this point in time, we all know what feminised seeds are, although even today there is some confusion regarding the most common methods to produce

How To Make Feminized Seeds At Home: A Complete Guide

Learning how to make feminized seeds deserves a spot on any sustainability-focused cultivator’s to-do list.

Fem seeds let you bypass the potential pollination struggle and cultivate only seedless buds every time. This variety (and its accessibility) is a gift that keeps giving, but some growers are after a higher level of self-reliance.

Feminizing marijuana might take some trial and error, but anybody can master it with enough dedication. Once you do, fem seeds of any strain you wish become available at any time.

Join us and discover how to feminize seeds at home.

How are feminized seeds made?

Before discussing how to make feminized seeds, here’s a short biology lesson to make sure everybody’s on the same page.

All marijuana seeds are ‘regular’ at first, developing into male and female plants at an approximately equal rate. Females produce buds, which serve as a holding space for new seeds upon pollination. Male crops create the pollen necessary for this process.

Males fertilize females in natural environments, causing more seeds to develop. That’s excellent for the persistence of the species, but it can be a pain for smoking purposes.

To make feminized seeds, you need to cross-fertilize one female plant with another. That way, no male chromosomes enter the picture, letting all offspring remain bud-bearing females.

Since female marijuana doesn’t produce pollen on its own, we introduce additional elements that enable fertilization. Here’s where another concept emerges—ethylene.

Ethylene is a cannabis hormone responsible for aging. Among other functions, it induces flowering, regulating how the plant expresses its sex. Females with low ethylene levels grow male flowers, making feminized cannabis seeds possible.

This process sounds like a whole lot of chemistry, manipulation, and trouble, and you might be reluctant to give it a shot. Let’s explore the reasons you’d want to pursue it.

Why should you make feminized cannabis seeds?

Fem seed varieties are all the rage on the marijuana market. Why bother with feminization when this variant is available for purchase? We’ll discuss how to make your own feminized seeds, but first, let’s see why you should do it.

Availability stands as the primary reason. While most cultivars come in feminized versions, not all do. You can only get regular marijuana seeds of certain strains, making sticky bud cultivation a hassle.

After feminizing marijuana, it produces hundreds (sometimes even thousands) of seeds.

What’s more, you could practice strain crossing without having to deal with new hybrid males. Knowing how to make feminized marijuana seeds lets you taste the results of your original idea in their full glory.

Growers on a budget reap extra benefits. Feminized seeds are usually more expensive than their regular counterparts, making this process an investment.

Of course, you could produce more regular seeds, but that means that about 50% of each garden goes to waste every time. Even worse—males could pollinate females, leaving you with more seeds but no buds to smoke.

Female seeds are a different story. They develop into fem crops 99% of the time, eliminating this headache-including concern. Making feminized seeds now brings the following benefits to every future cultivation journey:

  • No risk of pollination in your garden.
  • Seedless colas with a high smoke value.
  • Higher cannabinoid and terpene contents.

How to make feminized seeds at home?

As we mentioned earlier, studying how to feminize marijuana seeds incorporates various interchangeable methods.

Below, we share three ways to cause this structural shift in a female crop. Choose according to your skill level, desire for accuracy, and comfort with using chemical agents.

How to make feminized seeds using the rodelization method?

How to produce feminized seeds without using chemicals? Roderalization is an all-natural method of forcing female crops to develop male pollen sacs.

Staying seedless is an unnatural state for female cannabis plants. Like most things in nature, its main goal is to produce offspring and help the species survive. Evolution found a handy way to make this happen.

As the end of its life cycle approaches, a marijuana plant in nature develops male organs, self-pollinating to produce more seeds. Think of it as a last-ditch effort to propagate its genome.

Of course, any grower for smoking purposes would collect the colas before this happens. If you’re after new seeds, though, nature can do half the work for you.

Here’s how to make feminized seeds with rodelization:

  1. Care for your plant as normal until the end of flowering.
  2. When the harvest period arrives, don’t touch your plant.
  3. Let the crops sit under the same flowering conditions for two to three weeks.
  4. You’ll notice stamens and anthers (pollen-producing organs).

Feminizing marijuana this way is easy and cheap, requiring only time and patience. It’s ideal for first-time seed producers who aren’t comfortable with using chemicals.

Note that this technique can be a hit-or-miss, though. Even if there’s pollen, there’ll be much less to go around than with other methods.

Note: Although rodelization doesn’t produce hermaphrodites (crops with male and female chromosomes), their offspring have hermie tendencies.

How to make feminized seeds with colloidal silver?

While rodelization is great for first-timers, many growers seek efficiency and higher success rates. For that reason, they use colloidal silver to make feminized seeds.

Colloidal silver is a distilled solution of water and microscopic silver particles that inhibit ethylene production. You can get it commercially or make your own.

If you purchase from a store, get a solution with at least 15ppm silver. A product around 30ppm is ideal.

In the spirit of keeping everything sustainable and self-sufficient, we’ll provide an alternative to shopping. Here’s how to make colloidal silver at home:

  1. Gather supplies. You need a 9-volt adapter, two electrical wires, two clips, distilled water, two silver pieces, and a ppm meter.
  2. Strip the wires. This method of making a solution for feminizing marijuana requires unbridled electricity.
  3. Connect a clip to the end of each wire.
  4. Fix the wires to each end of the adapter.
  5. Place a piece of silver in each clip jaw.
  6. Fill a jar 3/4 full of distilled water and suspend clips on opposing sides of the container.
  7. Turn on the adapter and let it work.

The solution for making feminized seeds turns pale gold after around 20 minutes. The meter should read at least 15ppm silver, too. After that, all you need to do is let the liquid sit and cool.

Once you have your product, here’s how to make feminized seeds with colloidal silver:

  1. Pick a female crop that’s early into flowering. The earlier you start, the better the outcome.
  2. Soak the plants generously using a spray bottle. Focus the silver showers on future bud sites.
  3. Keep spraying daily for two weeks. Try doing it at the same time each day.
  4. Leave the marijuana plants to grow as normal.

You should start seeing pollen sacs within a month, but it’s a good idea to move these crops from any smoking-purpose plants right away. Otherwise, you’re running the risk of a random pollen burst fertilizing an entire garden.

Making feminized seeds with colloidal silver is straightforward and almost 100% guaranteed to work. The crop you used is a write-off, though. Colloidal silver travels through the plant, causing flower toxicity.

How to make feminized seeds with STS?

Making feminized seeds with silver thiosulfate (STS) is a recent technique, but its efficiency is helping it gain traction. It’s the only option that brings the 99% feminized figure of other techniques to a certain 100%.

STS is a solution of distilled water, sodium thiosulphate, and silver nitrate. It halts ethylene production, forcing male flowers to blossom. As with colloidal silver, the plants are no longer viable for consumption once you spray them.

Much like silver, the elements for STS are accessible in most pharmacies and online shops. You can make this liquid yourself or get a bottle on Amazon and go to town with it.

If you decide on the first option, you need to prepare two solutions and only mix them when it’s time for feminizing marijuana. Always use protective equipment and choose glass or plastic containers to avoid contamination.

Here’s the recipe:

  1. Pour half a liter of distilled water into a measuring cup. Measure 0.5 g of silver nitrate before adding it.
  2. Stir until the crystals dissolve. Pour solution A into a brown glass bottle.
  3. Repeat step number one with 2.5 g of sodium thiosulfate.
  4. Stir and pour into another bottle. You now have solution B.
  5. Combine 50 ml of solution B, 50 ml of solution A, and 800 ml of distilled water in a spray bottle.
  6. Add ten drops of washing detergent and lightly shake the mix.

The liquid should stick to leaves, not immediately slide down. If it does, you need more detergent in the blend.

Once the chemistry exercise is all done, here’s how to make feminized seeds with STS:

  1. Start spraying five days before the flowering stage. Focus on the leaf areas and be generous with the soaking.
  2. Continue spraying once every five days, covering the roots with paper to avoid damage.
  3. Continue for four weeks. Spray at night to help the crops soak in the solution.
  4. Leave the plant to develop as normal after the four-week mark.

You should see pollen after another month. If you notice any yellowing or burnt tips, add more water to your STS liquid.

This technique for making feminized seeds requires more caution, but it’s as effective as it gets. Once you master the application, STS massively reduces trial-and-error, making it even easier to move on to the next stage.

How to handle pollen for making feminized seeds?

The main section of making feminized seeds is over. Your female crops are now forming pollen sacs, and you’re soon to collect the precious substance and finish the cycle.

Let’s talk about the steps that follow feminization.

How to collect pollen

Collecting pollen is the next level of teaching yourself how to make feminized cannabis seeds. This one is all about timing.

As a rule of thumb, wait until the sacs swell but act ASAP once they do. Otherwise, they can burst and pollinate nearby female plants, ridding you of your precious source.

See also  How To Germinate Weed Seeds For Hydroponics

When the time is right, cap the top of your plant with a plastic bag. Fix the cover around the crop and remove the male flowers one by one. Be careful when grabbing them to avoid pollen explosions.

Leave the sacs to dry for a few days and filter them using a micron sheet. Place a sheet of parchment beneath and shake the pods, letting the golden powder fall and collect on the flat paper surface.

You can use this pollen to make feminized seeds right away or store it for future use.

How to store pollen

If you plan on making feminized seeds later, the pollen remains fresh for a week in the fridge and up to a year in the freezer. The key idea here is to avoid moisture.

Storage with cooking flour is the way to go for avoiding humidity issues. Combine the two powders, sticking to a 3:1 flour to pollen ratio. Wrap some paper around the mixture and place it inside an airtight, opaque container.

Tip: Reduce the amount of oxygen in the jar to further prevent degradation. You could also add paper, cotton, or rice to the container.

Wrap reusable bags around your container. Leave it in the cold spot of choice, staying vigilant about temperature fluctuations.

How to pollinate the plants

How to make female seeds? Pollinate female plants with female pollen. The process can begin as early as two weeks into flowering. The method depends on the number of seeds you’re looking to produce.

If you’re going for smaller-scale production, use a soft-bristled paintbrush to dust the pollen onto buds and branches. The spores stick to the trichomes, making fertilization easy to localize.

If you aim to make feminized seeds from an entire crop, there’s a quicker way to do it. Place the pollen in a bag and cover the crop with it, shaking to help it spread. Let the bag sit there for another day.

You’ll have to wait for another four to six weeks before the plant produces seeds. Keep providing optimal conditions during that time.

Grow female marijuana from your own stash

Bravo—you now know how to make feminized seeds, and you have tangible results as proof of your skill.

Take your time to master these methods before you make feminized cannabis seeds at home. Do everything right, and you’ll never again find yourself settling for regular varieties of hard-to-find strains.

Visit our store to find the best strains worth feminizing. Check out the post on recognizing quality seeds to ensure you’ve done everything right.

About the author: Parker Curtis

Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.

How to make feminized marijuana seeds

Want to learn how to make your own feminized marijuana seeds? So far in your growing process you have probably only worried about the ways to keep your plants happy and healthy – to both survive and thrive. Chances are, this has taken up most of your time.

Feminized marijuana seeds

It has probably used up more of your time than you ever expected. How could you even think about doing something extra for your next time around?

Download my free marijuana grow guide and start growing high-quality marijuana strains.

  • Grow with my Quick Start Guide
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  • Avoid common grow mistakes

The truth is, having one season’s worth of a great harvest is a good thing – but you could make it great by setting your sights on the future.

You have so far achieved some very difficult stuff during your grow season. Maybe you had to overcome unforeseen obstacles. Do you want to make things easier next time around?

If your plants are currently maturing, start taking a closer look at them. Are there growths forming at the spot where stalk and leaf connect? Are some of your plants growing tall and skinny while others are remaining bushy and short?

These changes come from your plants reaching their sexually mature stage. As soon as this starts happening, you should be able to accurately decide which plants you will want to reproduce so you have a stash of pot for the entire year. Do you know how to make feminized seeds, click here and learn directly how to make feminized marijuana seeds

In this article, we will cover the basics of looking to future generations of growing seasons. The secret of success is your plants’ seeds, as well as the sexes of those seeds.

How to sex plants

The first step in making these crucial decisions is to determine which plants are male and which are female. You should start being able to do this once the season starts to change.

As soon as the length of daylight falls below eighteen hours per day, you will begin to see responses in the male plants. They will start to grow bud-like growths, which are actually greenish-white flowers in the shape of an egg. You won’t be able to mistake its gender once you shake these flowers since they will give off a cloud of pollen.

About two weeks later you will start to see distinct changes in the females as well. They will start to grow buds, which begin as a little cactus-like white growth at the ends of branches.

These buds will grow and grow until about a month has passed, at which point they will be significantly larger, sticky with resin, and odorous. Depending on the strain you are growing, this odor could smell similar to a skunk, or it could have a sweet, pleasant smell.

  • Time your harvest for Perfect Taste
  • Get THC levels for a Perfect High
  • Don’t waste any Precious Bud

Surprisingly, you can get a pretty good idea of which plants are male before they start reacting to the changes in daylight. In general, the male plants will be the tallest of your crop.

This is a simple evolutionary trait that was naturally selected over generations – by being taller and maturing faster, males are more likely to successfully drop their pollen onto the female plants as they are budding. Taller males will also have their pollen travel longer distances in the wind.

These male plants also die sooner than females. Luckily for you, you can cut off their flowers and smoke or eat them (after properly drying them, of course). You will be pleased with the resulting high since it will be almost as good as smoking the female buds of your harvest later.

What is pollination

To seed or not to seed? That is the eternal question of many marijuana growers – especially new ones.

When left to their own devices, male marijuana plants will fertilize the females, causing a new generation of seeds to be “born.” While this may appear harmless to the uneducated grower, it can significantly decrease your resulting harvest.

THC-rich buds

When female plants are fertilized, they will slow down their production of resin, which has a high amount of THC. An unfertilized flower contains the most THC you can find on any marijuana plant. Additionally, unfertilized females can remain in the flowering phase for a long time – between six and ten weeks – meaning a higher amount of these THC-rich buds.

All this means that you will need to decide how many (if any) female plants you would like to be fertilized, and how many you want only for your harvest.

Protecting your females from fertilization isn’t as easy as it sounds, but it is crucial to you getting a successful harvest in the end. The most effective way to do this is simply by uprooting your males and taking them away from your at-risk females.

Ideally, you already took the high male-female ratio into account when you initially planted. Marijuana plants generally are 70% male, so removing all your male plants will reduce the number of plants significantly.

Remember that the end result will be higher, so don’t fear this process. That being said, you better be completely sure a plant is male before removing it from your crop.

There could be nothing worse than to uproot a plant you thought was male, only to discover you just killed a huge female plant that could have significantly contributed to your end yield.

Plenty of growers who only want the marijuana for their personal use will simply allow the males to pollinate the females, and will remove the marijuana seeds from the harvest later.

How to make seeds

This process is best for indoor growers, and it involves fertilizing your plants. To begin with, you must identify which plants are male and which are female (see above).

You will, of course, need at least one male to fertilize your females, but usually one is enough. Choose the one male plant that you think has the best qualities, then remove all of the rest.

The next step is to isolate this male plant so that you can control its lighting separately from the females.

While the females still have continuous light, your male plant should have 12 hours of light and 12 hours of complete darkness. This lighting change will spur the male into flowering and therefore producing pollen.

You should take this pollen and save it since you’re going to need it later. Use a piece of paper to get the pollen from the flowers, and then drop the pollen into an envelope. Stick the envelope in a freezer to keep it fresh.

Meanwhile, keep your female plants in their vegetation phase for as long as possible. Once it is time for the flowering phase to begin, it’s time to use the pollen that has been stored in the freezer.

Decide carefully which females you will want to pollinate. It could be because she exhibits specific qualities you like, or maybe she comes from the same strain as the male plant and it happened to be a great strain, so you want to keep the strain completely pure.

Place the pollen in one cola of the female plant(s). Don’t pollinate flowers on that same plant, and don’t get the pollen in the flowers of the other plants, either.

The process of pollinating your plants must be done carefully. For best results, separate the whole female plant to avoid contaminating the other plants around it.

First, put the frozen pollen into a little bowl, and get a small watercolor paintbrush. Use this brush to glaze the pollen on the top of your female plant’s cola.

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After four days or so, put the pollinated female plant under 12 hours of sunlight and 12 hours of uninterrupted darkness. This is the point when you no longer have to worry about cross-pollination since the pollen will be firmly stuck to the cola.

Keep a close eye on your pollinated female to make sure you harvest her seeds at a suitable time. Mature marijuana seeds will not be green, but rather will be some sort of brown color.

Once the seeds are mature enough, simply use your fingers to take them out. Label the container with the seeds and then refrigerate them all. As long as they remain cool and dry, they won’t lose their ability to germinate next season.

In the end, you will both have a nice, high-quality strain of seeds for your next growing period, and the rest of your unpollinated plants will produce wonderful weed. It is a great way to conserve financially while also increasing the quality of your future crops.

Feminizing seeds

At this point, you are probably thinking that the 70% male and 30% female average is pretty unfortunate. Most growers would agree with you. Unfortunately, you don’t have much control over your future plants’ genders when you use regular fertilization techniques.

This is why many take measures to make it more likely that they will get only (or mostly) female plants. One way to sway the odds in your favor is to feminize your marijuana seeds.

In general, you cannot tell the difference between male and female seeds. You also cannot change a seed’s gender. The idea behind feminizing your plants is to maximize the amount of females in your crop since female plants generally have a higher THC content than males, and, therefore, get priority.

Seed feminization utilizes a number of pollination methods to tip the scale in your favor. If you have some extra cash and aren’t feeling up to the challenge, you can also buy already feminized seeds from marijuana seed companies.

Buy feminized seeds

  • Every plant will produce flowers
  • No time wasted growing useless cannabis
  • Grow nothing but harvestable plants

That being said, buying feminized marijuana seeds online can often be hit or miss. Make sure the company you are buying from is reputable. This is the best seed shop online.

There are three types of feminization: silver thiosulfate, colloidal silver and rodelization. Each one, when properly carried out, should end up successfully giving you mostly female plant.

Silver Thiosulfate method

The new innovation if using STS (Silver Thiosulfate Solution) has somehow become commonplace – and it’s a great one because it is highly effective. It has allowed feminized seeds to be found everywhere, meaning that the average grower can buy feminized marijuana seeds.

Better yet, we can all rest assured that they are probably properly feminized, rather than the hit-or-miss feminized seeds market of days past.

So what is silver thiosulfate? It’s a half-and-half combination of sodium thiosulfate and silver nitrate. It simply causes a hormonal reaction of stress in the plant that triggers a change in gender.

So how do you actually create feminized marijuana seeds yourself? It involves a little bit more than drenching your plants in silver thiosulfate, unfortunately…

First you should decide which plants you’re going to use. They should all be female and from one strain, and nearly mature. Then just take one of them, separate it from the bunch, spray it with STS, let it dry, and finally replace it alongside its sister plants.

That plant will start looked very stressed out. It will turn brown and might worry you with how close to death it appears. Just five days later, however, it will begin its revival. In one month’s time, this plant will have finished its transition into being male.

At this point, you can simply shake the new male plant right over those same females, thus pollinating the female plants. Because the new male plant used to be female, the pollen it provides is actually female pollen. That means that, after just a couple of weeks, these pollinated female plants will create feminized seeds.

Although the process seems extremely simple, especially compared to other methods you may have heard of, this doesn’t mean you will have success on your first try. Luckily for you, breeders you might want to buy feminized seeds from always make sure each batch of seeds, along with the entire process, is successful.

They will, therefore, give you seeds that you can depend on. In fact, these days the highest end feminized seeds have a feminization rate of 99% or more, so this method is clearly a huge help to the marijuana industry.

Colloidal Silver method

For this method, you will need a very small amount of colloidal silver (pure silver) and distilled water. Put the former into the latter, then, using a spray bottle, apply the resulting mixture onto your female plants while they are flowering.

The plants will begin to form pollen sacs (which are normally seen on males). The pollen contains genetic material that is actually totally female – making it highly probable that the marijuana seeds the plant produces will be female.

That was the simple way of describing the process. Actually doing it is much more complex and involves many more details. In addition to the pure silver and distilled water, you need a 9-volt battery and connector, alligator clips, and soldering iron. Sound like too much trouble? Just buy colloidal silver online at this link here

Assuming you have no problem with spending the time and money finding these “ingredients,” the next step in the process is to connect the battery and its connector.

Solder the alligator clips onto the red and black wires to form the best electrical current. Then connect these to the silver (probably coins) that you have.

How to make feminised cannabis seeds

Until the 1990s, any cannabis cultivator was aware that, at some point, they had to separate the male and female plants if they didn’t want the first ones to pollinate the latter, which results in plants completely full of seeds. However, those were the days when pioneering seed banks like Dutch Passion were revolutionizing the cannabis scene with the birth of the first feminized cannabis strains, or in other words, seeds that only develop into female plants. At the beginning of the 20th century, many seeds banks were offering this type of seeds, feminized versions of classics strains that had been cultivated during many years as regular plants.

We are sure that by now you’d probably have grown some feminized seeds, maybe even though you are a purist and the fiercest defender of regular seeds. But. do you know where feminized seeds come from? Are you familiar with the processes used by both breeders and growers to obtain them? In this article we explain everything!

Feminized cannabis seeds quality control

Advantages of growing feminised seeds

Indeed, the advent of feminized seeds brought about a genuine revolution within the cannabis sector. Growers were now sure that all their plants would be females, without the need to differentiate between male and female plants or having to remove the males before they could ruin the crops, which offers a number of benefits of significant importance:

  • Space and resources saving: no more growing plants which eventually will be removed for being males.
  • Reliability: it’s not that most plants are female, or that they are genetically more likely to produce female plants. The plants grown from feminized seeds have only female chromosomes (XX), therefore this method is 99% reliable.
  • Sinsemilla plants: by not having males in the grow room, your female plants won’t be pollinated, so they won’t produce any seeds during the flowering period (something that every cultivator wants, unless they want to obtain seeds)

These advantages were of great interest for the growers, and soon feminised seeds accounted for a large portion of the seeds available in the market. In addition, being able to use only female plants (generally known and selected clones) to produce seeds had another great advantage for seed producers and breeders of new varieties: they no longer need to keep males in their gene pools! And not only that. from that moment on, any female plant they could get their hands on could be used as a male to pollinate other plants, thus exponentially increasing the possibilities of creating new crosses.

Outstanding Orange Candy feminised from Philosopher Seeds

It is not surprising, therefore, that at present, feminized seeds represent virtually all the seeds in the market, since they offer a number of significant advantages for both professional and home growers and breeders, for photoperiod and autoflowering plants. The main disadvantage of this method is a well known and hotly debated issue: the growers who buy this type of seeds cannot produce their own seeds in the absence of male plants, so the only way they can manage it it’s using the same process to obtain this type of seeds. But. what are these processes and what are they based on?

Female crosses: feminised cannabis seeds are born

As we’ve already mentioned, feminized seeds are the result of a process that reverses the sex of a female plant, that is, she is forced to produce male flowers. This way, and once into flowering, the female chosen will start to develop what we know as male flowers (stamens and anthers), which, just like male plants, will release the pollen that will pollinate the female plants. What is then the difference between a male plant and a reverted female plant?

The sex of cannabis plants is determined in the same way as ours, through the so-called sex chromosomes or genosomes. Male plants have a couple of different sex chromosomes called “XY” or heterogametic, while female plants have two chromosomes called “XX” or homogametic. When crossing a male (XY) with a female (XX), we will obtain around half of the plants of each type in their offspring. In other words, when a breeder uses a male and a female plant, the seeds produced by them will be approximately 50% males and 50% females.

After this explanation, many of you will have already figured out that if we cross two female plants (reversing the sex of one of them to force it to produce pollen), the result will be seeds that will produce female plants, as there are only female sex chromosomes in the equation. If crossing XY with XX produced 50% of each class (male and female), crossing XX with XX will produce plants that only exhibit chromosomes XX, that is to say, female plants. No matter how many times we “transform” a female plant into a male plant, we won´t be changing their genetic composition, which will still be female or XX. This way, the pollen produced by this plant will pass down female sex chromosomes exclusively.

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Feminised seeds grown indoors, 100% female plants

As you can see, and although we normally use the expression “reversing the plant sex“, that is not exactly what is done, because the sex chromosomes of the female plant (XX) have not changed, even if we managed to produce male flowers. This “sex change” of female plants can be achieved in a number of ways, but usually with the same goal: to reduce the level of ethylene in plant tissues and/or inhibit the ethylene action, which makes the plant develop male flowers on entering the flowering period, as if it were a male from regular seeds. This is because ethylene is a natural regulator of the sex expression in plants!

Let’s see now the most popular ways to reverse the sex of a female plant in order to produce feminized seeds.

Methods used to produce feminized cannabis seeds

There are several ways to secure that a female plant produces pollen, and almost all of them require some type of chemical that is often sprayed on the plant. Once sprinkled with the chosen product and under a flowering photoperiod, the plant will flower normally, but as a male instead of female, producing ‘feminized’ pollen (which only contains chromosomes XX) that can be used to pollinate other females in order to produce seeds. These are some of the most commonly used techniques:

Stress or rodelization

One of the first methods used to obtain seeds that produce female plants was stress or rodelization. There are several ways to stress the cannabis plants to make sure they develop male flowers, such as through temperature, nutrition, photoperiod, and pH. However, supporters of this technique often prefer something as simple as delaying the harvest 2-3 weeks in order to force the plants to develop a few male flowers without stressing them as much as with any of the other methods we have mentioned.

Although this action will produce far less pollen than other techniques like STS, it will be enough to obtain a handful of seeds for the domestic growers to try to create their own feminized crosses. Also, the great advantage of this technique is that is 100% natural, and it doesn´t use any chemicals. It is an excellent alternative for anyone who just wants a few seeds and wishes to keep it simple without any formulas or laboratory products. However, bear in mind that this is the only method listed in this post that may produce some plants with hermaphroditic traits.

Male flower produced by rodelization

STS or silver thiosulfate solution

Without any doubt, one of the most commonly used methods for both producers and seed banks. This is a solution made of distilled water, silver nitrate and sodium thiosulphate (sometimes called sodium hyposulphite) that, after being sprayed on the female plants, inhibits their ethylene action resulting in the formation of male flowers once flowering has been induced. STS is relatively easy to prepare, although its lifespan after combining the two components is quite limited, barely a few days as long as it´s well preserved (in a dark and cool place).

It is important to mention that you must not consume any part of the plants sprayed with this type of product, although that would be weird, as the plants have “become” males and won´t produce any buds. Nevertheless, you shouldn’t use the reverted plants to make resin extracts; the best thing is to discard them after harvesting the pollen. Both components, sodium thiosulphate and silver nitrate, are also used for photo-development.

Colloidal silver

This is another way to revert the sex of the plants, but this time using a solution made of 30ppm colloidal silver (that you can easily find in many pharmacies and also online) and distilled water. The solution must be applied for a few days until the plant starts producing male flowers, something that it´s not necessary with STS, where in most cases one single application is enough.

Colloidal silver is formed by electrically charged silver nanoparticles and has antibacterial and antifungal properties. This product was introduced in the market in 1980 for therapeutic use. However, as with STS, you should get rid of the sprayed plants once their pollen is harvested, as colloidal silver is absorbed systemically by the plant and remains in its tissues.

This sativa plant treated with STS started flowering as a female but soon developed male flowers

Silver nitrate

This is a method researched by Mohan Ram, who also conducted extensive investigations on plant sex reversal with STS. According to his findings, sodium thiosulphate (STS) is more effective in producing male flowers and viable pollen in female plants. Probably because of this, silver nitrate is mixed with sodium thiosulphate, instead of using it in isolation.

Gibberellic acid

Gibberellins are plant hormones that help regulate various processes related to the development of the plants. There are several types of gibberellins available in the market, although the most common and effective is gibberellic acid or GA3 (Gibberellin GA3). This product is used in a very similar way to colloidal silver, sprayed on the plants during several days before switching the photoperiod over to flowering.

It is worth stating that one of the side effects of gibberellic acid is a significant stretching of the treated parts of the plant, so don’t be surprised if this happens to your plants! The recommended dose to achieve the best results is approximately 100ppm.

Urban legends and lies about feminized seeds

Despite the fact that, after two decades of cannabis cultivation, many of the false myths surrounding feminized seeds have been debunked, from time to time we still hear some arguments like the ones shown below. As is often the case, many of these stories are spread by people who have never grown this type of seeds or have none or very limited experience with them. Ignorance is always a bad thing, and that’s why we want to emphasize several points in relation to feminized seeds and the myths that often go with them; myths such as the following:

Feminized seeds produce hermaphrodite plants:

The problem with monoecious hermaphrodite plants has more to do with the parents used (and if they exhibit any hermaphrodite trait) rather than with the type of seeds produced. If to create a feminized seed you use a female plant with a tendency to produce male flowers, part of its offspring will likely inherit that characteristic, whether the said female plant is used as a pollen donor (after reversing its sex) or as a recipient of pollen (letting it flowering as usual). Yet the same thing happens when producing regular seeds: if the male or female parents are not stable in this respect, neither will be their offspring (or at least part of it).

Marijuana and hermaphroditism

Many growers have been surprised by the presence of hermaphrodite plants in their marijuana crops. In this post we will tell you how to detect them and how to proceed if you find a hermaphrodite cannabis plant in your growing space. We will also discuss the causes of this hermaphroditism.

Feminized seeds produce mutant plants:

Nothing could be further from the truth. It is true that sometimes some plants develop weird traits or mutations, although this also happens with regular seeds. Unfortunately, there seems to be not enough studies comparing the ratio of specimens with mutations of one or other type of seeds; however, given the millions of feminized seeds that have been germinated in the last 20 years, if mutations would pose a problem, the quantity of feminized seeds sold would certainly not be so high, and this would be a “public security” issue within the cannabis sector, both for the growers and the producers of the seeds.

Feminized seeds have chemicals:

This is another lie that some people believe. As it’s been mentioned before, a female plant is sprayed with some chemicals in order to inhibit its ethylene action. After a few weeks of this and once in the flowering period, the plant will produce male flowers and pollen, which will be harvested to pollinate the female plants designated to produce seeds. Once the seeds are formed, they are collected and packed immediately, so they don’t come into contact with any chemicals or the plants that produce seeds, nor, of course, with the seeds themselves. Also, to produce cannabis seeds, you normally need two separated indoor cultivation areas, one for the reverted plants (treated females) and the other for the females to be fertilized to produce the seeds, so the latter can’t get “contaminated” with any chemicals.

Feminized seeds are GMOs:

Once again, this is a false statement. We have already pointed out that by using these sex reversal techniques we inhibit the ethylene action in the female plant, and under no circumstances the seeds (or plants) are genetically modified. The sex chromosomes of the female plant converted into a male plant are still female (XX), nothing has changed at a genetic level.

We hope you found this article interesting; even today, many people are still unaware of the intriguing process behind this type of cannabis seeds. Do not hesitate to leave your comments; we will be delighted to answer them.

  • Marijuana Botany, Robert C. Clarke
  • The Cannabis breeder’s Bible, Greg Green
  • The Cannabis grow Bible, Greg Green
  • Breed your own vegetable varieties, Carol Deppe
  • Induction of Fertile Male Flowers in Genetically Female Cannabis sativa Plants by Silver Nitrate and Silver Thiosulphate Anionic Complex, Mohan Ram, Sett R.

The articles published by Alchimiaweb, S.L. are reserved for adult clients only. We would like to remind our customers that cannabis seeds are not listed in the European Community catalogue. They are products intended for genetic conservation and collecting, in no case for cultivation. In some countries it is strictly forbidden to germinate cannabis seeds, other than those authorised by the European Union. We recommend our customers not to infringe the law in any way, we are not responsible for their use.

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