Can get granulated(powder) suffer and mix 8 ml per g in hot water(breaks down easier) then add cold water and spray. The pm thrives in lower ph, the suffer raises the leafs ph to over 7, pm does not like that on and will disappear quickly
Really
it depends on the light cycle outside. If you want her to stay in veg then add light either in the evening or morning to keep the plant from flowering, 16 hrs light usually helps