I am in a pretty hot zone as well, here in Austin, and I don't mulch. I think it's helpful if you're starting during a hot time of year, but if you're starting in spring, or staggering plants in mid-season, there should be plenty of shade to keep them moist. I am interested in other members feedback as well, though.

Interesting post; I just came in from mulching cabbage and here is a mulch question. On the cabbage it was planted for fall harvest the last of June the first of July. and I want to keep the soil cool so I just pulled some handfuls of grass along my raised bed and put in 2 inches loose. Another thing I just started was when I weed I put the pulled weeds in the square around the tomatoes (if The weeds are not yet seeded). They make a great but sparse mulch. I really go more by the amount of sun that hits the ground around the plant and watch the soil temperature more so than the water. Cultivating/hoeing will conserve the water

Curt~

I use straw as a vegetable mulch. It keeps the produce off the ground and conserves water. I am careful not to place it directly against the stems of the plant.

Where we get more than a few days of scorching 100+ weather, mulch is important. SFG beds are just not deep enough to retain what I consider optimum conditions, things will dry out more than I like. In this case mulch is a necessity, I use bark chips (free).

I usually pile on a few inches of grass clippings after I plant the tomatoes out. Then after a couple weeks it mats down and I put a few more inches of clippings down. Really suppresses weeds well. I still get the odd weed through the mulch after it's mated down again and mostly decomposed. Then I just throw more mulch down and smother them. I figure the clippings are free and it's not much extra work to bag the clippings every now and then and spread the out in the garden.