lack of pollen with STS


Welcome to the CannaZone
Jul 17, 2017
Reaction score
I'm currently trying to make some feminized seeds, but I ran into an issue with my first 2 reversed plants.

they're fully reversed, full of balls, no female flowers. however, the balls have trouble opening(some opened at the tip, but not fully, others fell of the plant unopened), and they don't contain any pollen.

I think this could be due to too high concentration and applying too frequently. I used a recipe that's floating around a lot of forums(adapted it a bit so I could make a smaller amount, and my sodium thiosulphate is pentahydrous instead of anhydrous, so I converted the amount from the recipe). however, instead of the 1:10 dilution in that recipe I switched to somewhere around 1:5 / 1:6 after first application, and I applied rather frequently, about once every 6-8 days, and those first reversed plants have had 5 applications total(one recently with lower concentration 2 weeks after the last before that, at the time I harvested those balls without pollen they had had 4 applications).

after searching around I did find a few comments of people dealing with similar issues, and read some comments saying it's due to too often/high dosage applications, and to stop applying immediatly upon seeing the first balls. however, most people seem to be using CS, and most comments I found about high/frequent dose and no pollen were with CS too.

so I'm, wondering if anyone with experience using STS can tell me if I'm thinking in the right direction, and lower/less frequent dose can solve my problems?

I already have some other clones going(of different plants) that I'm going to give a lower dose, the youngest have had their first application a few days ago, about 1:10 dilution(not very precise, just added water to the spray bottle containing the 1:5/1:6 dilution I had to make it roughly 1:10), and I plan on keeping 2 weeks between applications from now on.

also, could my already reversed plants start giving pollen later on if I don't do anymore applications on them?

(btw, I'm applying it using a pipette, putting droplets directly on the buds, used spray bottle the first applications, but with a pipette is easier and I use way less of my STS-solution)
an update for anyone else dealing with this issue that stumbles upon this thread:

on one of those reversed plants the effect of the sts seems to have expired(2 weeks after last application). it's newest flowers are female again.
it now also had a few opened balls(previously, the balls didn't open, except a tiny bit at the tip), and inside these opened balls there was visible pollen. still not as much as a real male, but enough to pollinate with.
so it seems ethylene is needed for ripening the balls(and producing pollen), so only after the sts-effect expires you'll get pollen from the balls created when it was still active.
and some last picture, it's working now.
some small clones treated twice with 1:8 dilution of the sts stock solution, not fully reversed so I'm getting selfed seeds from a single small clone, the plan was to collect pollen and pollinate the bigger motherplant, but this is even better, going to continue doing it like this so I can just keep a few small clones for seeds, and I could do something similar single seed descent:

Too bad no one saw this thread! Your concentration is way too high! 10 to 1 is the minimum! Think about this fully diluted to 10 to 1, you have 1.5 grams of chemicals in 10 LITERS of water! your probably looking at about 10-20 parts per million! This is potent stuff, and you only need to spray once. within 2-3 weeks you'll have pollen sacks.
what concentration are you using?

btw, don't know if it was clear that dilution was not dilution of pure sts, I first made a stock solution(with 0,25 grams of silvernitrate, and 2 grams sodiumthiosulphate, in 500 ml water), then I diluted that stock solution further with water before application(I'm still using from the first batch stock solution I made, I keep it in my fridge and when I need some I take out a few ml and dilute it)(I'm now also applying with a pipette instead of spraying, so each plant just gets a few drops)

often online I see people using stronger recipes or applying more often, so I thought my application was on the weaker side.
but if you're having success with a way lower concentration, I'd like to know which concentration, then I can try a lower dose next time and see if that still works.
i have same problems with lack of pollen... but im working with hemp, its very unstabile genetic.. sometime i have tons males flowers without any pollen :crying:
Females reversals will never drop pollen like a male, if ur looking for pollen to be everywhere like a male than someone misinformed you my friend. Reversals also don't always work thats why so many companies dont offer fems and other companies specialize in "fem only" I tried reversing my witch doctor 5 times over the last year and half only 2 were successful. I had plants i reverse a few females and only one takes. When it comes to collecting pollen from a reversal its way more than just shaking pollen loose some u really gotta dig in those balls and half the time not alot of pollen. The strong the genetics the harder it is to reverse, remember that.

Sts recipe 100mg of SN to 500mg of ST in 1L

Thats same recipe with work from some strains and not for others. If u want alot of fem pollen reverse more females:pass:
Here are my results with the solution made as per instructions, in fact, they have already released enough pollen to pollinate the female recipients, and the pollen sacks are just now bursting! One spraying was all it took.

mother plant:

Breeding motherpic1 -3-11-2018.jpg

Reversed Plant:

Reversed Breeding plant pic1 -3-11-2018.jpg
Also fresh batch of sts everytime, people say they can keep reusing sts with success ive yet to see a successful reversal when reused. 4 years of reversing plants all of my best reversals are with fresh batch of sts every spray. Even making new every week most people supplies will still last over a year. Dont worry about wasting because your not, its only a waste when ur plant doenst fully reverse so id have to suggest make a new mix every week. Spray 5-7 days is my SOP until u see Full ball sacs then stop and i start feeding "heavy" (heavy as u can with a auto) once sacs start forming.
Last edited:
anyone try freezing sts to preserve it?