If you have NGW tube in your room please check out this thread it sounds like your problem. I scratched my head for a year myself trying to figure it out.

http://boards.cannabis.com/indoor-gr...ml#post2145305
u.g.u Reviewed by u.g.u on . Leaves dying one week into budding Hey, I was growing for two years with no problems, but about a year and a half ago every time i try to bud the leaves turn yellow and die. They seem to be light sensitive the leaves on the sides or down low stay nice and green. Iā??ve tried moving my light further away, new bulbs, new room, and i have cleaned everything. I have thrips and have got rid of them on the leaves but they are still in the medium and i cant seem to get rid of them. just wanted to see if anyone had any ideas. Rating: 5