horsetail works but not 100% I'll try your tea method for sure ,how about late flower ?
(Horsetail) You can use it on harvest day if you like......does not add any smell or taste! late harvest is fine, but be sure to have fans on the subject plant to help prevent rot from too wet!
For better results with the HT. Mix a cpl of drops of dish soap into the tea water. Makes the surface tension of the water less and the HT will contact the molds better! Works great that way!
The "AACT light" for mold will work right up to the last 2 weeks!