I have used BT twice on my girls. Soaked the buds really good. Let them sit in the shade for an hour and then shook the stems to get all the extra off....then let them dry in the sun. I did the two sprays 2 weeks apart....haven’t seen any more caterpillars since and no adverse affects to the girls. There is a brand of BT called Monterey BT. It is 98.35% BT and only 1.65% other ingredients. I learned this after I purchased Thuricide brand which is only 15% BT. After some googling I did read that the other 85% was mostly water and something to prolong the life of the BT in the bottle....that ingredient wasnt listed. They are both marked organic so there’s that....