Growing from feminized cannabis seeds is a space and resource-efficient way of getting all females, all the time. Find out how to create your own feminized cannabis seeds. Feminized seeds come from two female plants being bred together, causing all offspring to be female. Because there are no male parents, all the resulting seeds end up being bud-bearing female plants. With feminized seeds, you know you can always count on every plant to produce buds, and don’t have to worry about removing male plants.
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.
How do you force a female plant to make pollen?
There are two main ways to make feminized pollen:
Induce feminized pollen chemically (Recommended) – This is the “professional way” to feminize seeds, and is how most reputable seed banks and breeders create feminized seeds to sell to the public. Substances such as colloidal silver and gibberellic acid are used because they cause a female plant to produce male pollen sacs if bud sites are drenched daily for the first 3-4 weeks after the switch to 12/12. This article will give you step-by-step instructions on how to feminize cannabis seeds using this method.
Rhodelization (Not Recommended!) – In the wild, some female cannabis plants will naturally start making male pollen sacs or “bananas” which can self-pollinate the plant. This happens if the plant is stressed, or if the plant is not harvested in time and buds start to die of old age. The plant is basically doing everything it can to save the next generation. This method is “natural” and these seeds will all end up being mostly female, but the problem is you’re selecting for plants that naturally hermie (grow both male and female sex organs) without any chemical induction. This means the resulting seeds are much more likely to turn hermie in natural conditions too. That’s a problem if you don’t want seedy buds every time you harvest. For that reason, it’s highly recommended you don’t feminize seeds this way, and it’s a good idea to toss any and all seeds that are the result of natural herming.
Read this article for more in-depth discussion about the pros and cons of each method, and how to avoid hermaphrodite plants when producing your own feminized seeds.
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.
INHIBIT THAT ETHYLENE
“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.
Macro closeup of feminized marijuana seeds
Overview: How to Make Feminized Seeds
1.) Buy or Make Colloidal Silver – The article below will teach you how to make colloidal silver at home, as well as show you where to buy it if you don’t want to make it (it’s actually pretty cheap!). It’s basically a solution of silver suspended in water and is available online and in health stores as a dietary supplement.
What about gibberellic acid? I’ve seen with my own eyes that the colloidal silver method works for making feminized seeds, but I don’t personally know anyone who has tried making feminized seeds with gibberellic acid. From what I understand it can be used exactly the same way as colloidal silver to induce female plants to produce pollen, but I’m not sure exactly how to prepare a gibberellic acid solution that works consistently.
2.) Spray the bud sites of your known female plant daily during first 3-4 weeks of the flowering stage (until pollen sacs form and start splitting open) – After switching to a 12/12 light schedule, choose bud sites on your known female plant, and spray/drench them daily with colloidal silver (or gibberellic acid). As the treated flowers develop, they will form into male pollen sacs. Untreated bud sites on the plant will form into female buds as usual; however these buds are unsafe to smoke unless you’ve been very careful to make sure they didn’t come into contact with colloidal silver or gibberellic acid during the feminization process.
3.) Harvest “Feminized” Pollen – When pollen sacs are ready to be harvested they swell like a balloon and start to open up. Make sure not to harvest early and also make sure to keep spraying the bud sites daily until this point or you might end up with empty pollen sacs! When the pollen sacs are ready, the leaf section protecting the pollen will start to crack. At this point it’s time to collect the feminized pollen. One of the easiest ways to do this is to collect the pollen sacs directly and let them dry for a week. At that point they can be placed in a bag and shaken to easily collect all the pollen.
4.) Pollinate Another Female Plant – At this point, take the feminized pollen you’ve collected and use it to pollinate a female plant that has been flowering for about 2-3 weeks (full detailed instructions with a video on how to do this below). Although it’s possible to pollinate the same plant as the original, it’s not recommended in part because the timing doesn’t match up (attempting to pollinate buds too late in the flowering stage leads to reduced seed production). It’s best to pollinate a different female plant that you started budding a few weeks after the original. This increases the number of seeds produced as well as gives the new female plant enough time to develop them to maturity. It also increases genetic diversity compared to self-pollination.
5.) Wait ~6 Weeks to Harvest Seeds – After about 6 weeks from pollination, the calyxes on the buds of your female plant will be swollen and fat. You know it’s time to harvest your seeds when they start bursting out. At this point, it’s time to congratulate yourself because you’ve got feminized seeds!
Now that you’ve gotten the overview, here’s the feminization process with detailed step-by-step instructions…
Step-By Step Instructions
1.) Buy or Make Colloidal Silver (or Gibberellic Acid)
Where to get Colloidal Silver (your options):
Buy “ready-to-use” colloidal silver for cannabis seed feminization on Amazon. Colloidal silver is sometimes used as a dietary supplement, so it’s relatively easy to find (never take it without talking to a doctor first though!). If you’re purchasing colloidal silver, try to find a solution that has at least 30 PPM (parts per million) of silver or higher.
Buy A Colloidal Silver Generator Kit: If you plan on feminizing a lot of seeds, you may want to invest in a generator kit so you can easily make your own endless supply of colloidal silver.
Make Your Own: You can make your own colloidal silver generator at home. The following diagram illustrates what you need to do.
Note: You can purchase gibberellic acid online (a giberellic acid solution can be used the same way as colloidal silver for feminizing seeds). However, I do not have experience with the gibberellic acid method and don’t know the best way to prepare the solution.
MAKING YOUR OWN COLLOIDAL SILVER
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.
WHAT YOU WILL NEED
A power adapter—9–12 volts is ideal, or a 9-volt battery. Higher voltages can be used, but you really need to know what you are doing so you don’t get electrocuted.
Electrical wire. One length for the positive and one length for the negative.
Distilled water. This is easy to find at your local supermarket. Do not use tap water as it has too many impurities that can harm the process.
Pure silver, at least 99% pure. Silver coins are ideal and relatively inexpensive. They are available on eBay, coin dealers, and mints. Silver wire gets results, with some reports that silver solder works also, although it is unknown what the other metals in these alloys might do. Going with a source of pure silver is safest.
Small alligator or crocodile clips to hold the silver.
A ppm meter.
Make sure the adapter is set at 9–12 volts.
Strip each end of the wires using scissors or wire strippers.
Securely connect the alligator clips to one end of each wire to ensure a good flow of current. Soldering is best.
Fix the wires to the positive (red) and negative (black) terminals on the unplugged adapter or onto the battery.
Put a piece of silver in the jaws of each clip. Don’t touch them together. Fill a glass jar or glass beaker ¾ full with the distilled water. 500ml will easily do two plants.
Suspend each silver/alligator clip combo in the water on opposite sides of the glass.
Plug in and turn on the adapter. If you are using a battery, the process began the moment the electrodes were submersed in the water.
After 20 minutes, remove the electrodes and test with the ppm meter. 15ppm (0.5) and over is the goal. The solution should become a pale gold color.
When finished, clean the black silver oxide off the silver electrodes and put the kit into storage until next time.
Store the colloidal silver in an amber-tinted bottle in a cool place. It is light and temperature-sensitive. However, don’t put it in the fridge.
2.) Spray the bud sites of your known female plant daily during first 3-4 weeks of the flowering stage (until pollen sacs form and start splitting open)
When you’re ready, change to a 12/12 light schedule in order to initiate flower formation. For photoperiod plants, wait until your plant is 5-6 weeks old before initiating the flowering stage. Some young plants seem to have trouble (and take much longer) to go through the feminization process, and their pollen may not be as fertile, so start with a more mature plant.
As soon as you change the light schedule (and maybe even a day or two before) start spraying your plants thoroughly with colloidal silver at every bud site you want to form into pollen sacs.
Spray bud sites thoroughly, drenching them with colloidal silver every single day
A diagram showing where to spray colloidal silver to produce male pollen sacs. The plant should be sprayed thoroughly at bud sites (where leaves meet a stem)
The above pic shows you where pollen sacs form on the plant (same places female buds form)
Important! Keep spraying daily until pollen sacs open up. Don’t stop spraying early, even if pollen sacs appear to be already formed, otherwise they may not produce much pollen!
A one-hand pressure sprayer / mister is really helpful for spraying bud sites evenly and thoroughly
You can choose to treat a single bud site or all the bud sites on the plant. Any untreated bud sites will develop into female buds as usual. If you want to smoke these buds, it’s incredibly important to avoid letting them come into contact with colloidal silver as that’s not safe to smoke. (Don’t worry, feminized seeds don’t contain any silver). I highly recommend letting the whole plant be your test subject so you don’t have to worry about that 🙂
Note: If you’re feminizing an auto-flowering plant, start spraying daily when the plant is about 20 days old from seed. This is when most auto-flowering cannabis strains start making flowers.
3.) Harvest Your Feminized Pollen
When pollen sacs are starting to crack and look like they’re about to open up (or if you can see one has already opened) then your pollen is ready for harvest!
There are a number of harvesting methods employed to catch pollen.
One way to harvest your pollen is to gently and carefully remove all the pollen sacs. Let them dry for a week, and then put them in a resealable bag. If you shake the bag the pollen should easily spill out. You may need to cut a few open yourself.
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 watercolor 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.
How to Store Feminized Pollen: Moisture is your main enemy when storing pollen. It can help to double the mass of the pollen collected by adding regular cooking flour. This absorbs moisture during storage and as an added bonus, it will make application easier when you get to pollinating. If you triple-bag the pollen-flour mixture and stick it in the freezer (with a good nametag so you know where the pollen came from), your pollen can be stored for a year or longer.
4.) Pollinate Another Female Plant
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.
Only the buds that come in contact with pollen will grow seeds. You can choose to pollinate all of your buds or just a few on the plant.
Make sure that you’re touching all the female pistils/hairs with your pollen. Here’s a little video showing you exactly what this looks like!
5.) Wait ~6 Weeks to Harvest Seeds
It usually takes about 6 weeks for your feminized seeds to fully develop. Some plants are literally dying right as the seeds become ready, so to get the most viable seeds, you need to try to keep it alive until the seeds actually start dropping. The seeds can be used right away, or stored in a cool, dry place for a few years. Don’t forget to label them with the date!
With a bit of aforethought, it is possible to set up an efficient feminization breeding program—and have female seeds from your favorite phenos on hand all the time. You never know, you might discover the next big thing!