Ok, so the title basically says it all. With the exception of cloning, this is the next best way to continue your grow room and, get a high percentage of female plants. I will start out with the organic, and highest success rate for female seeds. Some growers might say some methods work better than others, but the general idea is the same, we are looking to get female seeds with the highest success rate. There are many different methods to making feminized seeds, though there is debate on which methods work best and yield rewardingly.
Many know this method as the "Rodelization" method, created and used by many growers, soma seeds uses this method, as well as most seed banks. It is written about, and endorsed by "High Times".
Basically what you need to do is grow a healthy female plant (not from feminized seeds!) take care of it all the way throughout the entire grow, under optimal conditions. You can start flowering about a month and a half after seeds sprout, by this time you should have roughly 7-10 nodes. Allow this female plant to flower longer than normal, approx 7-14 days after expected harvest. By this time, you should start to see "nanners" or "pollen sacks" on the buds, this is a safety mechanism that mother nature uses to ensure survival of the species. To most, a male banana is quite a beautiful thing. It has the potential of making all female seeds.
In the Rodelization method, the male banana is very valuable. After growing your female plants 10-14 days longer than usual, hang them up to dry, then carefully take them off the drying lines and inspect for bananas. Each and every banana should be removed, and placed in a small bag labeled very accurately. These sealed bags can be placed in the fridge for one or two months and still remain potent.
For the next phase, you need to have a separate crop thatís already 2 1/2 weeks into flowering. Take your sealed bags of pollen out of the fridge, and proceed to impregnate your new crop of females with the nanners that you saved. To do this, you must first match the female plant and the pollen from the same strain in the previous crop. Shut all the fans in the grow room down. Then take a very fine paintbrush, dip it in the bag of pollen, and paint it on the female flower. Do this to each different strain you have growing together. Many have done it with up to 10 different kinds in the same room with great success.
You can also use this pollen to make new female crosses by cross-pollinating. The older females with the male bananas can be brought into the room with the younger, un-pollinated females after they are three weeks into flowering. Turn all of the circulation fans on high, and the little bits of pollen will proceed to make it around the room. Do this for several days. Six to seven weeks later, you will have ripe 100% feminized seeds; not nearly as many as a male plant would make, but enough to start over somewhere else with the same genetics.
Colloidal Silver Method
Colloidal silver is available from your local chemist (in low parts-per-million though), and is drank for good health (the silver helps kill bacteria etc). But its PPM is too low for what we intend to use it for - feminized seeds! So we need to make our own with a higher PPM ... no problems, we simply allow the electrical current to flow through the silver for a longer duration.
TO MAKE A COLLOIDAL SILVER GENERATOR ...
You will need: a 9V power adapter that outputs DC, two alligator clips, a soldering iron + solder. (If you don't have soldering iron you can simply wrap the wire around the alligator clip base in a coil and that will suffice, but you'll get better contact if you solder it).
- Get a power adapter that has an output of 9V DC 600mA or thereabouts. Output must be DC, and 9V/600mA seems optimal from what I've read and been told *You can use a cable modem power supply for this*
- Cut the end off and discard
- Split the main wire into its two smaller sub-wires (no need to pull them apart all the way though). Don't worry, we don't need to know which is positive/negative.
- Use wire-cutters to remove the plastic shielding/insulation to expose the actual metal wires, about 1 inch is enough
- Solder the wires onto alligator clips ($0.50ea from your local electronics store)
If you don't have alligator clips, a good alternative - drill a hole into each coin and coil the wire around that instead.
TO MAKE COLLOIDAL SILVER ...
- Get some distilled water. Do not use any other type of water due to impurities. At your supermarket you may find distilled water next to spring water, but it may also be in the ironing products isle as it is commonly used for steam irons.
- Attach each alligator clip to a chunk of PURE 999 or 9999 SILVER
- Make sure each coin is half-dunked in the water, but that the alligator clips themselves aren't touching the water, then turn on your generator and leave it for about 7 hours.
Similar to this picture:
The end result: the electrolysis causes microscopic silver particles to be suspended in the water (= colloidal silver aka CS). The rig basically looks like this when in use (the only thing in contact with the water is the silver, not the alligator clips or anything else):
It's also recommended you use an airpump with a clean (not used for anything else) airstone to help keep the water moving.
Also you don't want to leave the CS generator running TOO long or the silver particles in the water start getting too large - ~8 hours should be plenty.
USING COLLOIDAL SILVER TO MAKE FEMINISED SEEDS ...
Start spraying your target plant with CS just before you send it into 12/12 flowering, and keep spraying every few days. I won't go into details, but the CS causes the female to produce male flowers/pollen. Collect that pollen, and use it to pollenate another female (you can pollenate the same female that you CS'd (aka "self'ing") and indeed you may have to if you have a clone-only strain, although that may lead to more hermaphroditic traits, but I wont go into details on that). Anyway, because you've pollenated a plant with pollen from a female, the pollen can only create female seeds.
There's obviously a lot more to it than that but hopefully this brief explanation will help people understand the basic jist of it.
ps. I don't recommend drinking home-made CS unless you've done your homework because the PPM may be too high, which is great for making feminized seeds (we need a higher PPM for that) but may have risks with human consumption - too much silver can cause argyria, a condition of blue or gray discoloration of the skin, so always buy it from your chemist if you intend to use it medicinally. Also if you do drink it medicinally it's recommended you also take additional probiotics (like Yakult), because the silver also kills a lot of the good bacteria inside you. So do your homework first!
Good luck on your feminizing! There are more methods, but I happen to favor these over the others, at least you know your plant won't die from stress and be a complete failure (i.e. light stress, heat, nutes, etc.)