Sorry, but it's probably downey mildew. Peas and squash seem to get it in my garden as soon as the weather starts getting hot and humid. There's some fungicides you can try, but usually (for me) the plants stop producing once the mildew gets going, so I pull them and put them in the burn pile instead of compost. Sorry.

Are you trying to harden them off? Are they close to a window and have you had freezing temps outside? If you are trying to harden them off, you may have put them out for too long. If they get too much sunlight and they are not use to it, it can burn the leaves. However the leaves turn white. If you still have then inside, and the leaves are touching the windows and you had freezing temperatures at night, you may have frozen the leaves. Unfortunately, I've learned both of these things from experience.

Hi - thank you all for your help and advice. So I've checked the soil under the surface and it's very damp. Initially when the leaves started turning yellow I mistakenly thought that they weren't getting enough water so made the problem worse. I'm going to try not watering them for a while (I'll try a couple of weeks as suggested). I've also loosened some of the soil up a bit to make it easier for the water to evaporate. The window is facing South-East so not ideal but the best one in the Apartment. I'm thinking of getting a grow lamp of some sort to help them out. How many hours of direct sunlight do they need? Or is the answer "as much as possible"? We're in Virginia and so they peppers are pretty warm through the day particularly when in direct sunlight. I guess it's fingers crossed now and see how they recover. I've been checking out a few of the pepper pictures on the board and am jealous - hopefully I'll be able to followup with some decent pepper pics of my own. Thank you again.

New growth isn't a clear indication that the plant is growing. True growth is measured by a plant's increase in dry weight; so, if a plant is shedding a leaf and growing a leaf, it's roughly in a static state, which is not a good place for a plant to be. I'm not necessarily saying the leaf ISN'T being shed as a result of normal senescence, only that new growth might not indicate an o/a increase in mass. There is no better fertilizer program than one you can control to the degree you know exactly what nutrients your plant is getting, how much of each, and when nutrients will be available for uptake. There is an ideal level of nutrients in the soil and an ideal fractional amount of each in comparison to each and all of the others. Most plants use about 10X as much N as P, and about 3/5 as much K as N. The rest of the nutrients also have an ideal level determined by a function of N levels and the overall level of total dissolved solids (TDS) in the soil solution. Adding tonics, miracle concoctions, or supplements targeting an increase in 1 or 2 nutrients w/o good reason or a strong likelihood what you are doing is going to correct a deficiency, is far more likely to result in limitations than benefits. Al