While major planting projects should wait for fall's rains and cooler temperatures, fill in empty spots in beds with summer color. To increase beneficial insects, try calendulas, cosmos, salvias, and sweet alyssum.
Plant carrots, corn, and green beans from seed. For carrots, make sure soil is loose, well tilled, and free of rocks.
During hot weather, check container plants frequently to make sure they aren't drying out; they may need water daily. Trees also need regular, deep watering every few weeks--even some natives, such as coast redwoods, can look very scraggly without irrigation. A notable exception? Many kinds of native oaks resent summer water.
Pick green beans every few days to keep the plant producing. Shelly beans, such as cranberry or kidney beans, should be picked when the pods are dry and begin to shatter.
Zucchini and other summer squash are tastiest when picked relatively young; do not let the fruit linger on the vine or it will become too large and fibrous.
Yellow jackets can be a persistent backyard pest. Reduce their population with reusable yellow-jacket traps (available from any garden center), baited with pheromone attractant that must be replaced every two to 10 weeks, depending on the brand and formulation. Traps can be placed about 20 feet apart for effective coverage but will not be enough for an active nest; those should be dealt with by a pest-care professional.
Roses can fall prey to fungal infections such as black spot or rust in areas with summer thunderstorms or in coastal regions that get summer fog. Fight back using a nontoxic method: Pluck off and discard any affected foliage (do not compost), and apply horticultural oil monthly.
Twelve pianos will be placed throughout the San Francisco Botanical Garden's 55 acres this month. Between the scheduled professional performances, the pianos will also be open to anyone who wants to make music alfresco. Jul 13-24; free for San Francisco residents, $8 nonresidents; sfbotanical garden.org/flowerpiano.