Dissolve 0.85 g silver nitrate in 50 ml distilled water (Part A)
Dissolve 0.80 g sodium thiosulfate in 50 ml distilled water (Part B)
Put each stock solution into a separate amber bottle, wrap in foil and keep in the fridge.
Slowly add 10 ml Part A into 40 ml Part B, with shaking. This is your 20 mM working solution. The mixture will keep for about a month in the fridge in an amber bottle, but then should be discarded. The separate Part A and Part B solutions are more stable and can be kept in amber bottles wrapped in aluminum foil in the fridge until needed. They will freeze solid @ 4C - just take them out and defrost before mixing them together.
Take the preflowering target plant out of the tent and spray the entire plant thoroughly (leaves, stems, etc.). Allow it to dry fully (takes a couple of hours) before returning it under the light or the spray will damage the leaves.
Repeat the spray protocol five days later. If you are worried, you can do it one more time five days after the second time, but it usually doesn't need it.
Both silver nitrate and sodium thiosulfate are available on Amazon in powder form (links above). I would not purchase the liquid form, as the dry powder lasts much longer than the liquid. I mix up only what I think I might use for the plant.
Safety:
Always wear gloves when working with these solutions. If you are spraying, wear eye protection. Do not get it on your skin or on other plants unless you plan on reversing them as well.
