Agreed dragonfly, peppers can grow in crummy soil. However, not to be rude or anything, we're trying to figure out what's wrong with Mark's peppers, not yours. Just curious, why don't you mulch them? Just don't feel it's necessary?
I've grown peppers and tomatoes close to each other before with little problem, and the soil was the same, so it's hard to say whether it's the watering or soil. Fertilizers often come as "tomato and pepper food", so they obviously share some needs. The herbicide issue was just something that happened to me years ago and I was sharing an experience to give some food for thought.
How about this? A good foliar feed might straighten out the problem. I'd suggest seaweed. I did a little reading and found that a late frost or dramatic temperature change could bring on the same effect. These are signs of stress in any case. A good handful of cornmeal watered in at the base would probably do good for them too. So there you are, lots of ideas to help you! Let's hope you get great peppers this year.
Kathe
