Complete Guide To Using STS To Create Feminized Seeds

Starting STS soon on 3 Autoflowers… pineapple Xpress auto Girl Scout Cookies auto and Tangie auto…
plants 11 days old… I have read until I am blue in the face and cannot find specifics on when they start spraying Auto’s(it seems like putting bits and pieces together start spraying the minute I see pistols)???
So, I may start spraying around day 18 to 20… 6 sprays until male flowers appear & 10% mature ???

Does anyone actually have experience with autos?
NOT PHOTOS?

Thoughts welcomed 🎶🪴🎶
 
Hi there. Mate from experience with autos you cannot start spraying early enough. For me. If I see pistols it’s 2 late. The autos go so fast. I have had success with spraying from 14 days old. Treating them every 5 days until I can see the male flower forming. Once I see the flowers forming I stop as I find more spray after that produces male flower with no pollen.
Hope this helps.
 
Grilson said:
Hi there. Mate from experience with autos you cannot start spraying early enough. For me. If I see pistols it’s 2 late. The autos go so fast. I have had success with spraying from 14 days old. Treating them every 5 days until I can see the male flower forming. Once I see the flowers forming I stop as I find more spray after that produces male flower with no pollen.
Hope this helps.
Click to expand...
Thank you, Interesting, food for thought…experimentation time… the Tangies flower @ 18 days, from 3 past grows with these seeds.
But, great smoke
 
I wonder at what day the big Seed Suppliers start spraying STS on auto flowers to produce feminized seeds, good luck finding that information???

(I will try Day 14 from your advice)
 
Birdies said:
I wonder at what day the big Seed Suppliers start spraying STS on auto flowers to produce feminized seeds, good luck finding that information???

(I will try Day 14 from your advice)
Click to expand...
Here are photo's from two Critical Mass Autos today. They are the same age - started in the first week on Oct. I sprayed one with STS once per week starting late November. It's had about 4 sprays so far and you can see buds are forming. One more spray should do it. I've included the non-sprayed plant so you can see the difference.

Pic buds.jpg


Pic flower.jpg
 
Hi all,

according to this meaningful 2018 study ...

Foliar Sprays of Silver Thiosulfate Produce Male Flowers on Female Hemp Plants

Interest in hemp (Cannabis sativa) for its medicinal compounds, cannabidiol (CBD), and Δ-9-tetrahydrocannabidiol (THC), continues to increase. Maximizing yield of CBD and/or THC requires female plants because female inflorescences accumulate significantly greater concentrations of these...
journals.ashs.org

and this source ...

..as well as the study they are based on from the early 80s, the STS should be prepared with a molar ratio of 1:4.
If my calculations are correct, that would mean a weight ratio of 5.835:1 for the two components using the Pentahydrate version.

Many older tutorials seem to have taken the second source with its 20/80 solution mix and just quadrupled the amount of Silver Nitrate to get the same amount of A/B solutions, but this lowers the total dosage by a factor of 2.5 because the additional water also dilutes the other component accordingly! However, the very high amount of 20 mM would then still come out as 8 mM, or 0.8 mM after 1:9 dilution. Good enough, but not perfect, as the first source above suggests.

For the ~3 mM solution from the study with nearly 100% success, that would be 0.1g Silver Nitrate and 0.58g Sodium Thiosulfate mixed with 100 ml of distilled water each (=2.92 mM), NOT diluted any further.

Application is done 3 times: once directly before switching 12/12, once a week later, once another week later.

I have found this to work perfectly as long as temperatures are not too low. I did have problems with plants in a basement at 14°C. No problems at 20°+ and complete conversion.

The amount of pollen starts very small but gets larger later. What helps a lot is drying the sacks or, later, the entire plant, because otherwise moisture from the plant tissue soaks up the little pollen there is. For this, flowering has to be induced a few weeks earlier than for the one that is to be pollinated, but just a week earlier works as well.
 
Spray autos early drench her!!! As others said…
(I kept spraying and spraying finally around day 52 or so. I posted it somewhere but forgot pollen sacs started !

1698695614715.png



Prepare a 0.1 M Sodium Thiosulfate(STS) stock solution by dissolving 1.58 g of Sodium Thiosulfate (Product No. S7026) into 100 mL of water. Prepare a 0.1 M Silver Nitrate stock solution by dissolving 1.7 g of Silver Nitrate(Product No. S7276) into 100 mL of water. Store the stock solutions in the dark until needed to prepare the STS.
In general, the STS is prepared with a molar ratio between silver and thiosulfate of 1:4, respectively. Nearly all of the silver present in the solution is in the form of [Ag(S2O3)2]3-, the active complex for ethylene effect inhibition.
Prepare a 0.02 M STS by slowly pouring 20 mL of 0.1 M silver nitrate stock solution into 80 mL of 0.1 M sodium thiosulfate stock solution. The STS can be stored in the refrigerator for up to a month. However, preparation of the STS just prior to use is recommended.
***********
My seeds generated eventually from STS Tangie’Matic auto pollen produced
(spray early and often I didn’t get pollen until in the 50 day range can’t remember exactly when I started day 18 or so, as others said…day15 why not… just keep spraying !)
 
Hi there,

I started spraying my plant a day before I flipped the light.
I've been spraying the nodes every 4 days.

In the last week I have noticed that flowers are starting to form, and not the pollen sacks.

Could it be that my solution is no good?
Should I give up, or keep spraying every four days?

Hoping someone can help me on this as i feel a little helpless.
 
afroshin said:
Hi there,

I started spraying my plant a day before I flipped the light.
I've been spraying the nodes every 4 days.

In the last week I have noticed that flowers are starting to form, and not the pollen sacks.

Could it be that my solution is no good?
Should I give up, or keep spraying every four days?

Hoping someone can help me on this as i feel a little helpless.
Click to expand...
Hi afroshin, I've seen it happen a few ways so I'd expect it may be working. So every 4 days for how long, 2 weeks? Hang on someone with more experience might be able to say more. I know it might be done and ok but not sure. @InTheShed did your experience go like this at all?
 
afroshin said:
Hi there,

I started spraying my plant a day before I flipped the light.
I've been spraying the nodes every 4 days.

In the last week I have noticed that flowers are starting to form, and not the pollen sacks.

Could it be that my solution is no good?
Should I give up, or keep spraying every four days?

Hoping someone can help me on this as i feel a little helpless.
Click to expand...
What spray are you using?
 
superflow30 said:
What spray are you using?
Click to expand...
I'm using the STS spray, the bottles are light proof.. have done everything correctly.

I did keep the silver nitrate and the Sodium Thiosulfate in the fridge for about 9 months before I used them to make the solution. I just figured it would be OK as I kept them cool.
Could this be a reason it may not be working.

I don't know if I should proceed or pull the pin?

thanks for the support and look forward to any advise.
 
StoneOtter said:
Hi afroshin, I've seen it happen a few ways so I'd expect it may be working. So every 4 days for how long, 2 weeks? Hang on someone with more experience might be able to say more. I know it might be done and ok but not sure. @InTheShed did your experience go like this at all?
Click to expand...
it's about 2.5 weeks. I've sprayed them about 4 times now, would need another spray tonight.
 
StoneOtter said:
Hi afroshin, I've seen it happen a few ways so I'd expect it may be working. So every 4 days for how long, 2 weeks? Hang on someone with more experience might be able to say more. I know it might be done and ok but not sure. @InTheShed did your experience go like this at all?
Click to expand...
afroshin said:
it's about 2.5 weeks. I've sprayed them about 4 times now, would need another spray tonight.
Click to expand...
I mixed my A and B per these instructions but I didn't have much success with a 90/10 mix of STS. I now use a 50/50 mix per the instructions in this video, and I spray 3 days before flip, the last day before 12/12, and every three days after until I see male parts start to form.
 
What does 0.1 means and what if we only have sodium thiosulfate pentahyrate? Thx
Birdies said:
Spray autos early drench her!!! As others said…
(I kept spraying and spraying finally around day 52 or so. I posted it somewhere but forgot pollen sacs started !

1698695614715.png



Prepare a 0.1 M Sodium Thiosulfate(STS) stock solution by dissolving 1.58 g of Sodium Thiosulfate (Product No. S7026) into 100 mL of water. Prepare a 0.1 M Silver Nitrate stock solution by dissolving 1.7 g of Silver Nitrate(Product No. S7276) into 100 mL of water. Store the stock solutions in the dark until needed to prepare the STS.
In general, the STS is prepared with a molar ratio between silver and thiosulfate of 1:4, respectively. Nearly all of the silver present in the solution is in the form of [Ag(S2O3)2]3-, the active complex for ethylene effect inhibition.
Prepare a 0.02 M STS by slowly pouring 20 mL of 0.1 M silver nitrate stock solution into 80 mL of 0.1 M sodium thiosulfate stock solution. The STS can be stored in the refrigerator for up to a month. However, preparation of the STS just prior to use is recommended.
***********
My seeds generated eventually from STS Tangie’Matic auto pollen produced
(spray early and often I didn’t get pollen until in the 50 day range can’t remember exactly when I started day 18 or so, as others said…day15 why not… just keep spraying !)
Click to expand...
 
Queenbees said:
What does 0.1 means and what if we only have sodium thiosulfate pentahyrate? Thx
Click to expand...
Not sure what the 0.1 is but the measurements for both types of sodium thiosulfate are in the original post of the thread:

Mr. Krip said:
  • Fill the 500ml container with 500ml of distilled water
  • Measure out 2.5 grams of sodium thiosulfate anhydrous, OR 3.9g of sodium thiosulfate pentahydrate
Click to expand...
 
:nicethread: :green_heart:
 
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