What causes leaves to slowly curl down?

I just noticed that the biggest leaves on my good looking jalapeno plant are starting to curl under too. They aren't burn't, they still look vibrant green so it doesn't appear to have a deficiency I don't think. I'll have more pics to help with diagnosis as soon as i can. They are curling slowly to where the leaf tip points back toward the main stem. Any ideas on how to fix this?
I've noticed this on mine also, here in SoCal it has been getting to like around 50 degrees fairenheit :Shivers: :) . and I think that may have something to do with it.
Nope, no spider mites. Plus I have some neem oil so I'm ready for them if they come. Could it be from low temps? I keep a fan blowing directly on the lights, so it doesn't get too warm near the plants. Probably around 70 or so.
Hrm, dunno, my leaves keep curling down a little, but overall the plant looks happy. No burns, no holes, no bugs. Dunno, maybe its just a curled leaf phenotype? The purple one's leave quit curling, so maybe the jalapeno will grow out of it. I just transplanted it into a nice big 1 gallon pot. I read somewhere that peppers are one of the few plants that actually like being transplanted. And I was surprised to see how well the roots had already started to ball up around the outside in that little 4" pot i had it in.
My leaves on a Hidalgo plant are curling under as well, but I think that's the way Hidalgos just are. Would be grateful for confirmation if anyone else has them.

As long as the leaves aren't floppy and saggy, I normally take that as a good sign.