There are always plenty of different issues it could durive from. From my experience I could relate the leaf curling to lack of calcium but that might not be the case. I zoomed in on the first picture and noticed severe Edema which means that your plants are up-taking water faster then it can release it. I could be wrong and if I am please correct me fellow chiliheads. Edema is not usually that serious but it looks pretty bad on that plant. If I were you I would try and water less. Only when the leafs are wilting pretty bad. Keep doing that enough and maybe it will make it's way out of it. My plants had it pretty bad and once I got in a routine of watering them only when they absolutely need it then the very small gathering of tiny white bumps all over started to slowly disappear. If that's not it maybe it's because of the humidity?

Here is a picture of what mine had looked like

I don't see edema but maybe a close up pic of the underside of leaves might help.

Looks to me more like a situation of temperature issue. When leaves curl up like that, it's usually in response to "protection." Not that the plant actually needs more water, but the plant "thinks" it needs more water because of the higher temps and humidity.

No way of getting it outside during the day, maybe? Or is still too chilly where you're at?

Do the leaves relax a bit when the temps lower? Any way of bring down the temp of the greenhouse just a tad? Like maybe 5-10 degrees?

Let's wait until others chime in. Maybe the experts have something to offer.

Kevin

Either I'm blind or you didn't zoom in enough haha. Someone please tell me they see what I see on the under leafs?

Moruga,

I was thinking possible edema as well, I just wanted to get another opinion. I haven't watered since Saturday and the new growth is starting to look a bit better. It's more of a shiny green instead of a dull green like the other leaves. I'm wondering if I'm going to end up needing to cut off the old growth at some point or if it should be OK to leave.

Woohoo,

I was also concerned about the temp and humidity since that is a definite difference between the healthy and unhealthy plant. It's still too early to take these outside, I'm in zone 7. Maybe middle of May if I'm lucky.

I've opened the door on the greenhouse a couple of weeks ago to let a little of the heat and humidity out, but I may take the greenhouse down entirely if that does end up being the problem. My new seedlings in the same environment seem the be healthy though which then leads me to think over watering again.

Defenitly cut some old growth off. The new green color is a very good sign. Time will tell.