Feminizing using STS -INSTRUCTIONS-

[MTheory]

I just found this in another forum. I have no idea where it came from originally. The following must be done with female clones. The reason for that is bacause it will be started before flowering and only male flowers will form.

The following is a safe, inexpensive, and successful method for reversing the sex of female cannabis plants. Individual plant responses may vary based upon strain, but I can verify that this process is fully effective in stimulating profuse staminate flower production.


This process can be used to:
A: create new feminized seeds from solitary prize mothers that you currently have
B: create interesting feminized-seed hybrids from different prize strains that you currently have
C: create feminized seeds for optimum outdoor use
D: accelerate the "interview" phase of cultivation, in searching for interesting new clone-mothers
E: reduce total plant numbers- great for medical users with severe plant number restrictions
F: increase variety, by helping to create stable feminized seedlines to be used as an alternative to clones

At the bottom of this post are some specific details about the chemicals used, their safety, their cost, and where to get them.

It is important to educate yourself about cannabis breeding theory and technique prior to using a method like this one. [removed dead link]

It is also important to use basic safety precautions when mixing and handling these chemicals, so read the safety data links provided. The risk is similar to mixing and handling chemical fertilizers, and similar handling procedures are sufficient.

Remember: nothing will ever replace good genetics, and some of your bounty should always go back towards the professional cannabis breeders out there... the ones who have worked for many generations to come up with their true-breeding F1 masterpieces. Support professional breeders by buying their seeds. [removed link to shut down bank]

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Preparation of STS:
First, a stock solution is made. It consists of two parts (A and B) that are initially mixed separately, then blended together. Part A is ALWAYS mixed into part B while stirring rapidly. Use distilled water; tap water may cause precipitates to form.

Wear gloves while mixing and using these chemicals, and mix and use in a properly ventilated area. A mask will prevent the breathing of any dust, which is caustic. STS is colorless and odorless, and poses minimal health risks if used as described here. (See material safety data sheet links below). Note that silver nitrate and STS can cause brown stains upon drying, so spray over newspaper and avoid spilling.

Part A: .5 gram silver nitrate stirred into 500ml distilled water
Part B: 2.5 grams sodium thiosulfate (anhydrous) stirred into 500ml distilled water

The silver nitrate dissolves within 15 seconds. The sodium thiosulfate takes 30-45 seconds to dissolve.

The silver nitrate solution (A) is then mixed into the sodium thiosulfate solution (B) while stirring rapidly. The resulting blend is stock silver thiosulfate solution (STS).

This stock solution is then diluted at a ratio of 1:9 to make a working solution. For example, 100ml of stock STS is added to 900ml of distilled water. This is then sprayed on select female plants.

Both the stock STS and the working solution should be refrigerated after use, as well as the powdered chemicals, to avoid activity loss. Excess working solution can be safely poured down the drain after use (with ample running water) with negligible environmental impact. It's pretty cheap.

Each liter of stock STS will make ten 1-liter batches of working solution of STS. With the minimum amount of base chemicals ordered from Photographer's Formulary (see link below), this means that each 1-liter bottle of working solution STS costs less than 9 cents, and can treat 15-20 mid-sized plants. That's 200 1-liter batches of STS for $18. Note that the distilled water costs far more than the chemicals.

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Application:
The STS working solution is sprayed on select female plants until runoff. Do the spraying over newspaper in a separate area from the flower room. You probably won't smell anything, but ventilate anyway. You now have what I call a "F>M plant"; a female plant that will produce male flowers.

After the F>M plant dries move it into 12/12 immediately. This is usually done three to four weeks prior to the date that the target (to be pollinated) plants will be ready to pollinate. Response times may vary slightly depending upon the strain. More specific times can be determined by trial with your own individual strains. In my trials it took 26 days for the first pollen. 30-35 days seems optimum for planning purposes.

So, assuming that a target plant needs 3-4 weeks to produce fully mature seeds, a strain that takes 8 weeks to mature should be moved into flower at about the same time as the female>male plant. A target plant that finishes flowering in 6 weeks needs to be moved into flower later (10 days or so) so that it doesn't finish before the seeds can fully mature.

A seeded individual branch can be left to mature on a plant for a bit longer, while harvesting the other seedless buds if they finish first. Just leave enough leaves on for the plant for it to stay healthy.

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Effects:
Within days I noticed a yellowing of the leaves on the F>M plants. This effect persisted for two weeks or so; after this they became green again, except for a few of the larger fans. The plants otherwise seemed healthy. No burning was observed. Growth stopped dead for the first ten days, and then resumed slowly. No stretch was ever seen. After two weeks the F>M plants were obviously forming male flower clusters. Not just a few clusters of balls, but complete male flower tops. One plant still formed some pistillate flowers, but overall it was predominantly male.

It is strange indeed to see an old girlfriend that you know like the back of your hand go through a sex change. I'll admit that things were awkward between us at first.

When the F>M plants look like they may soon open and release pollen, ( 3-1/2 to 4 weeks) move them from the main flower room into another unventilated room or closet with lighting on a 12/12 timer. Don't worry too much about watts per square foot; it will only be temporary.

When the pollen flies, move your target plants into the closet and pollinate.

A more controlled approach is to isolate the F>M plants in a third remote closet (no light is necessary in this one, as they are releasing pollen now and are nearly finished anyway). In this remote other closet the pollen is very carefully collected in a plastic produce bag or newspaper sleeve and then brought back to the lighted closet, where the target plants are now located. If this is done, be careful to not mix pollen types by letting the F>Ms dust each other. Avoid movement, or use yet another closet.

Take special care to not let pollen gather on the outside of this bag- a static charge is sometimes present. Drop small open clusters of blooms inside and then close the bag at the mouth and shake. Important: next, step outside and slowly release the excess air from the bag, collapsing it completely, so that pollen doesn't get released accidentally. Points downwind; don’t let it get on your hands or clothes.

This collapsed pollinated bag is now very carefully slipped over only one branch and is then tied off tightly at the mouth around the branch stem with a twist tie or tape, sealing the pollen inside. Let the bag inflate slightly with air again before sealing it off, so the branch can breathe. This technique keeps the entire plant from seeding. Agitate the bag a bit after tying it off to distribute the pollen. Don't forget to label the branch so you know which seeds are which. Other branches on this same plant can be hit with different pollen sources.

If no lighted closet is available, the plant can be moved back into the main room, but- be very careful: pollen is sneaky. After 4-5 days, the bag is gently removed and the plant completes its flowering cycle.

Yet another method has worked well for me. I position the target plants in a non-ventilated lighted closet, and then I collect pollen on a piece of mirror or glass. This is then carefully applied to the pistils of one pre-labeled branch by using a very fine watercolor paintbrush. Care is taken to not agitate the branch or the pollen. No sneezing. The plant needs to be in place first; moving it after pollination can shake pollen free and blow this technique.

Regardless of technique, at completion you will have feminized seeds. Let them dry for 2-4 weeks.

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About the chemicals:
Silver nitrate is a white crystalline light-sensitive chemical that is commonly used in photography. It is also used in babies' eyes at birth to prevent blindness. It can cause mild skin irritation, and it stains brown. Avoid breathing. I didn't notice any smell or fumes, but ventilation is recommended. Be sure to wash the spray bottle well before you use it elsewhere; better yet: devote a bottle to STS use. A half gram is a surprisingly small amount; it would fit inside a gel capsule.

Where to get the chemicals:
photoformulary.com http://www.photoformulary.com

silver nitrate: 10 grams: $10
sodium thiosulfate (anhydrous): 100 grams: $3.95
Postage runs around $4. Fast service. [verified!]

Have fun experimenting with this technique. Use it responsibly. There are a few good threads here at CW that goes into the pros and cons of transsexual agents and feminized seeds. Read them. And most importantly, use STS with quality F1 strains developed by professional breeders for the most consistent results

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[MidgetMan]

If anybody had a hard time understanding this article here is a grow about it being done.

http://www.highbred.net/forums/index...l=Silver&st=10

[hashaman]

Hey, let's use our fancy chemicals to fuck with plant genetics and let's see what happens! I strongly believe that techniques such as this lead to unstable genetics down the line (i.e. greater propensity towards intersexed traits, loss in vigor, etc.) However, I haven't seen any long term studies as it were on plant growth after the application of "transsexual agents" as the article puts it, so I say this only on my own intuition.

That said, ethylene gas exposure is safer, less costly, and much easier. From Cannabis World (the origin of the article you quoted):

Treatment of hempseed with ethylene gas will increase the resulting number of female plants by about 50%. Ethylene is produced by certain plants (i.e., bananas, cucumbers and melons), and these can be used to treat hempseed in a simple manner. About two weeks before you plan to sprout the seeds, place them in a paper bag or envelope and put that in a plastic bag with the peels of a ripening banana or cucumber. Replace the peels after a couple of days, and change the bags to prevent mold.

Basically, germinate the seeds on paper towels like you normally would but keep a banana peel in the bag, and change bags/paper towels/peels every second or third day to prevent mold. Alot easier than fucking around with chemicals, eh?

[doobie_d]

dudes!!
the easiest way i've found of growing you're own stock of feminised seeds is really easy!

1. start with a strain that tends to have hermaphroditic qualities, Trainwreck immediatly comes to mind here!!!
2. fuck with the light cycle something bad! let light in during the dark time (only an hour or 2 at a time) and vice versa (best in the middle of the cycle), really confuse the plant and stress it out.
3. your plant will become hermaphroditic and pollenate itself
4. when a female plant with the chromosone xx pollenates itself the pollen is also xx, therefore any seeds produced will always have the xx or female type!

easy to do, may take a few tries to do it right but then you have a bumper crop of your own, inexpensive feminised seeds!

[cateros]

Have any of you ever heard of leaving one female on the table 10-14 days after she should be done flowering to try and make her grow a few male flowers because it seems all plants have potential to go hermaphrodite when no males are present especially when stressed by leaving them to flower longer you get male flowers and no seeds the thc prolly drops off a bit but you pick off the male flowers once they get nice and yellow store in a test tube and when your next grow goes to flower you take the individual bananas out of the tube with tweezers and lightly pain the pollen on to the lower buds you want to impregnate you only get a few seeds this way but as the flower is hermaphroditic and used to impregnate a female plant I have read it will give you a 80-90% feminized ration of seeds . Its basically a emergency self preservation of the species mechanisim. If you have heard of this or done it let me know if it works as I would love to produce a bunch of feminized seeds for emergencies like poweroutage or some other catastrophe that wipes out your grow or the rare case when your mother gets so old they can some time just auto flower no matter what the light is at

[john]

Originally Posted by mtheory

quote: "support professional breeders by buying their seeds. [removed link to shut down bank]"

roflmfao

[That_One_Weed]

instead of all those chemicals..just spray some 60ppm solution of colloidal silver on em to make ur girl produce male pollen sacks....BTW colloidal silver isn't dangerous..infact a couple sprays of that in the nose or mouth every day will help you from getting sick....i found this other method of creating pollen sacks on a plant that is 100% all natural and non dammaging to your plants..hers the link if any of you are interested

Marijuana Seeds Guide - Create feminized cannabis seeds

[tama]

Originally Posted by hashaman

Hey, let's use our fancy chemicals to fuck with plant genetics and let's see what happens! I strongly believe that techniques such as this lead to unstable genetics down the line (i.e. greater propensity towards intersexed traits, loss in vigor, etc.) However, I haven't seen any long term studies as it were on plant growth after the application of "transsexual agents" as the article puts it, so I say this only on my own intuition.

That said, ethylene gas exposure is safer, less costly, and much easier. From Cannabis World (the origin of the article you quoted):Basically, germinate the seeds on paper towels like you normally would but keep a banana peel in the bag, and change bags/paper towels/peels every second or third day to prevent mold. Alot easier than fucking around with chemicals, eh?

if your interested in
ethylene gas pm me all females