1. Is there a way to plant my garden so the heat-tolerant veggies protect fragile plants?Yes. Know what zone you're planting in and pick plants that grow well in that climate. Create boundaries with taller plants on the west side of tender plants (for example, taller okra can protect the shorter pepper plants).
2. What's the best kind of mulch for keeping soil moist?
Any kind is better that none -- as long as its composted. Avoid the use of fresh mulch like grass clippings or fresh manure, which can deplete the soil of nitrogen. Plastic mulch is good for things like tomatoes, because it helps minimize soil-borne diseases. For a single season, it will also keep weeds away. But clear plastic generates a great deal of heat and can make soil too warm; opt for red or black. Avoid recycled rubber mulch -- it cannot be tilled into soil, which you'll want to do at the end of the season.
3. Do soaker hoses work better than regular sprinklers?
Yes. I'm a firm believer in soaker hoses. There's virtually no evaporation, because the water goes right into the soil and isn't getting on foliage. You can direct the water directly to where it's needed most.
4. Once a plant wilts, can I save it?
If you catch it early enough, it doesn't mean you've lost the plant. Some plants naturally wilt at the end of the day as a natural defense, then spring back in the morning.
5. How can I tell if I've overwatered my veggie plants?
Ironically, overwatered plants will look the same as a drought-stricken plant: it will wilt, droop and turn yellow. Be aware of both rainfall and how much water you've added. Poke a finger in the soil, if dirt remains on your finger, there's enough moisture in the soil.
