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Side by side STS recipe experiment

Country Mon

Active member
Recipe #1:

First, a stock solution of 1.0L is made. It consists of two parts (A and B) that are initially mixed separately, each into 500ml of water, 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. Note that silver nitrate and STS can cause brown stains upon drying, so spray over newspaper and avoid spilling.

Part A: 0.5 grams 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 (part A, 500ml) is then mixed into the sodium thiosulfate solution (part B, 500ml) while stirring rapidly. The resulting blend is silver thiosulfate solution (STS, 1000ml).

This stock(STS, 1000ml) 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.

Hey guys -

It's great to see my old recipe is still out there and being used! I spent about a year back in 2003-2004 working with many different concentrations to come up with this formula before releasing it to the public domain on Cannabis World, so medical patients wouldn't have to worry about plant numbers being wasted on having to deal with (and count) true males. Of course that didn't stop people from continuing to present it as their own to make $$ from it, but whatever. Glad people are using it. That is what is most important.

For those wondering, I disappeared because after I released the public domain version on CW, the DEA decided to put silver nitrate and sodium thiosulfate bought together on the watch list. This was because I put a link in there to Photographer's Formulary, and their sales suddenly went through the roof to the point where someone traced it back to CW. That was not something I wanted any part of, so I decided to move on. CW went offline shortly thereafter.

The basis I used for this formula was an old reference from a '70s hemp cultivator who was using silver nitrate solution to reverse plants. STS is also used extensively in the cut-flower industry to preserve flowers by inhibiting ethylene. That info is still out there somewhere I bet. It never got into any specifics about the actual dosage the farmer used, so that was why extensive trials were necessary. I burned the hell out of quite a few plants to find the sweet spot. I also had a lot of discussions with a breeder named Fet. Not sure where he ended up.

Anyway. The formula as written above is usually effective, but some strains need to be hit just a bit harder. Spraying twice is a good idea; I hit them 5 days before flower and then again at 2 weeks of flower. I find that 1:9 to 1:5 is the zone of most success for me. But to be honest, it doesn't always work out the first time. Each cultivar responds a bit differently. I have found that blueberry strains can be difficult, along with Flo and a few others.

I have learned through countless trials since then that too concentrated a level of STS (stronger than 1:4) seems to somehow inhibit pollen formation or pollen release in some strains. The staminate blossoms still develop, though. I have seen the most beautiful all-male floral expression and then found it to be sterile; either no pollen at all or no apparent fertility.

For this reason I still begin with the 1:9 ratio and then work my way stronger to about 1:5 if there are problems, which are usually related to pistils still forming. There is a strong urge to want to hit the plant harder, and that urge to fix what isn't necessarily broken can work against you. Pick a strategy and stick to it; adjust stronger and try on another cutting of the same plant only after you have problems.

One thing new that I do these days is use a tiny pinch of yucca extract as a surface tension breaker; it results in a more even coverage on the plant.

Happy trails and best wishes from Country Mon. We've come a long way in the last 16 years! :tiphat:
 

Douglas.Curtis

Autistic Diplomat in Training
Awesome!

Excellent information, thank you for sharing the details. I completely agree about the yucca extract, I picked up a quart and it's amazingly effective. Probably last my little grow over a year. ;)
 
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