What does this mean? (Pic)

What does this mean when your leaves start curling up like this?

it could be a number of things, ph is off, to much heat, magnesium deficency

I would say it's too hot

well i just had a period where i didnt water the plants for about 5 days could it be that they just didnt have enough water?

Its nothing to really be worried about. When the leaf edges curl up like in your pic, it is most likely the case of salt buildup around the roots. I've had the same problem with my plants before. Flush whatever medium your growing in with plain water. Then right after you flush pour in a very diluted mixture of water and epsom salt. This way you removed the salt buildup, and you added magnesium. If is was either of those causes(almost positive it is) then you should now be all set. Also, make sure the temps in your room don't exceed 80 F. What lights are you using and how close to the plant are they. Do you foilage feed at all? If you do, make sure you only do it like 10-20 mins before the lights go off. Also make sure theres a fan in the room for some constant airflow.

You know, you really dont need to worry so much, I have a few curled leaves on my plant to. When growing pot its always good to remember, its always a plant, Rip that sucker right off or some shit. It'll be fine. If there is a real bad problem. Your plant would just curl a little bit. But, it is probably because u didnt water for 5 days though. Dont be such a Paranoid Stoner. Eaiser said then done though. I know. but i do promise you IT WILL BE OK!

sweet thanks a lot guys n girls