FIND a place in the shade, pour yourself a tall iced tea and take the next month off. There is not much for gardeners to do in the hot July garden other than water and weed. Everything needs watering this dry year, even normally drought-resistant plants that barely got wet this last winter. And every gardener knows that weeding is never done. The philosopher who said that work well done never needs doing over never weeded a garden.
If your summer water bill suggests that maybe the garden uses too much, don't change your plant palette now. Wait for fall or early winter (late October to February), when most nonthirsty plants grow, and when whatever winter rains we get will help them become established. It takes a lot less water to help plants become established in fall than in summer.
In the meantime, save water by using it wisely. Make sure sprinklers are in good repair and working properly. If water is running down the street, or blowing away as mist, something is wrong. Maybe the water pressure is too high (install a pressure valve) or the nozzles spray too far (swap them out for more efficient kinds). There are special nozzles for awkward strips and parkways that don't throw as much water onto the street or walkways.
Set sprinklers so they come on early in the morning, around 4 a.m., when there is no wind to blow the mist out into the neighborhood. Early irrigations also give plants plenty of time to dry before nightfall, which helps prevent disease and cuts down on damage caused by slugs and snails, which need moist soil to travel on. If you are irrigating when it is still dark outside, occasionally turn on the system during the day to check for leaks and broken nozzles. Mulches help keep soils cool and moist.
Irrigations should be thorough, and as infrequent as possible, to encourage roots to go deep in the soil, where moisture does not evaporate so quickly. Though lawns may need more water than other parts of the garden, they also benefit from deeper, less frequent irrigations, which help prevent weeds and disease.
Why did they wilt?
On really hot days, plants sometimes temporarily wilt when they simply can't take up water fast enough. They should perk up as the sun sets, but it might take them all night to completely recover. It's OK to cool them off with a quick spritz if you feel compelled to do something. But soaking plants that have adequate water, and are only temporarily wilted, will not help and may actually make things worse by keeping the crown too wet, encouraging disease. Root rot, usually brought on by too much water, looks just like lack of water--the plants wilt but additional water will only finish them off. Before watering, check to make sure the soil is dry an inch or two down.
Because they are pot-bound, container plants need lots of attention. In summer, pots can quickly dry out and may need watering twice a day in full sun. If you're going away for even a day, move them into partial shade where moisture will last longer. Always water until you can see it run out the drainage hole. This washes harmful mineral salts out of the pot. It also washes out fertilizer elements, one reason container plants need more frequent fertilizing than plants in the ground. Don't overdo it though, as it may bring on more growth than you want and require you to water even more.
Vines often stop producing fruit when the days and nights get too hot, but they will begin again as the weather cools. Watch for the green, knife-edged, keel-backed treehopper. Their young look quite different -- black and spiny. They can be crushed with gloved hands (they're very prickly) or dispatched with soap sprays. Look for tomato hornworms, which can quickly defoliate stems. Because they're green, they're hard to see even though they may be several inches long, so watch for the black droppings. The bugs must be handpicked. Gloves help. Don't over-water tomatoes. Too much brings on rampant growth and little fruit. Too much can also split fruit, encourage disease or rot roots. Water deeply when you do, so it soaks a foot or more into the ground.
Weed it or weep
Summer weeds produce an abundance of seeds, so get after spurge, chickweed and the ever-present oxalis. If weeds succeed in producing seed, they may overwhelm the garden next year, when it all sprouts. Weed with a pry tool since soils are hard and dry and weeds won't come out without a fight.
Leave the roots behind and they'll be back in days. Use a bucket so seeds can't escape. Be sure to dump them in the trash, not the compost pile.
A few weeds, such as false garlic and certain oxalis, have underground bulblets that sprout after the main plant is pulled. If weeds keep coming back in the same place, suspect that some part was left behind and dig a little deeper next time, making sure you get every little bit.