Only the tips of my 2 foot tall veg plants are curling pretty hardcore downwards. Definitely did not over water. Drainage seems to be fine. Ph has been a steady 6.5 all 8 waterings since I bought the clones. Gave one small dose of superthrive two weeks ago. Temperature fluctuates from 70 to 90 throughout the day and night in my grow room/garage. Please tell me what's going on and how to fix this someone!