ok, some of the advice in this thread is not helpful.
First thing, it sounds like your plants are hardened off, and should have no problems being in direct sun. Your experiencing drooping, not sun bleached leaves. Intense sun is not your problem. I grow in temps above 100 with an UV index of 10 on a daily. Scratch that off your list.
Second: I am worried how you determined you are watering properly? What makes you say this? How much water are you using? You said you dug a hole for your plants, how large? What is the surrounding soil like? Clay?
From what you have been saying, it sounds like under watering to me. I would double your watering and see if they respond.
On the flip side of that coin, I would also worry about over watering. Since you dug a hole into native dirt, sometimes that means you have really well draining soil that you added to a hole that doesn't drain at all. Hence leaving your roots sitting in a puddle of water.
Another possibility is your low on calcium. Does the plant just droop, or does it also have weird new growth? Could also be excess boron, but I doubt it.
Figure out how to post up a picture and we will have this solved right away.
