Leaf curl! help?

just relax, try to keep temps w/lights on under 88 and over 50 during lights out with a 20 degree difference at least if you can manage it between the 2. she'll be ok. don't freak over every little thing. Symptoms you see today were likely caused days ago and you are just seeing the results when the problem is likely solved. You probably got a lil over heated yesterday or a few days ago.

 

what are your temps and humidity?
get the humidity up to about 60 or 70% if you can, keep the temps Idealy lights on around 80-85
lights off around 60 - 70 not less than 40 lowest but I think growth stops around 50 degrees. I think your problem is heat I have plenty links on nute problems and such too.
Here's one
The Complete guide to Sick Plants,pH, and Pest troubles! - International Cannagraphic Magazine Forums

and another one if you need them.
Cannabis Growing Guide

 

Had this problem too. It's low humidity coupled with high temps. Good temps are actually around 70-75 if you can manage with 80-85 being acceptable with good humidity ranges. Tips for getting high humidity include using a humidifier. $30 for a cool mist humidifier dropped my temps about 4* and raised my humidity by a good 15%. Put styrofoam cups full of water around all your plants and if you can, hang wet towels over a bucket full of water, using the towel like a wick. These things together can raise your humidity 20-30%.

 

It'll help a little but not more than 2-3% which isn't much in the scheme of things.

 

80 is a great temp. If they are sativa they will want it hot and go fine up to 90 but it will affect the trich production. 80 is great. How about freezing say four or five gallon milk jugs and swap them out? set the fan on top somehow.
I'm all about ghetto if it works and saves $$$.

 

chime in over there any time. glad to have ya.