wilting in the desert

I started some white buddha dwarfs on april 28th they started to get the female hairs on the 21st of may and since then they are wilting leaves are turning yellow at the bottom. I got some fox farm open seseme used 1/2 tsp per gal and they really perked up then i water after i water about 1 1/2 hours they start to wilt again. I'm using a 400 wt hps in a 66x30x15 file cabinet 6 in exhaust threw cool tube,four 6 in intake vents 1 9 in and 2 6 in fans temps are between 70 and 82 degrees lights are 24" from plants. New leaves have yellow tips please help if you can thank you.

if its yellow at the bottom of the plant then nute poisoning is a for sure. look up what changes in nutrients u need for flowering stage. the bottom of the plant turns yellow usually when the bottom leaves are rubbing up against the soil