I don't know for sure, But when I added a 400w HPS the temp. got to 90 deg. and a within a week, my leaves curled like a claw. I killed the HPS and went back to CFL and some leaves look better. I have no idea what the real problem, also PH was high 7 almost 8. I fixed that problem, maybe this is what is happing with yours.
I for sure am not the one with the answer. Good Luck.
Vinman Reviewed by Vinman on . BIG PROBLEM WITH LEAVES!!!! For some unknown reason the leaves on my plants are curling downward dramatically, like a claw almost facing the other way, the tips have turned a golden brown (worse on a particular node)and the bud is turning light brown(only on top though). I have recently brought the plants in from the outdoors due to a dramatic dip in temp and transplanted into pots. I have them under a 400w hps light, they were fine a few days ago, smelling very nice but now they look a bit sorry. is it something ive done Rating: 5