Early in the month, sow seeds of cool-season veggies, such as carrots, chard and spinach.
Late in the month, sow seeds of warm-season crops, such as beans, corn and squash, and set out seedlings of eggplant, peppers and tomatoes.
Prized for their rich flavor, heirloom tomatoes are becoming more widely available as seedlings in retail nurseries. This might be the year to try a new variety.
Continue sowing lettuce greens by planting a small batch of seeds every two weeks until daytime temperatures stay around 75 degrees. To beat advancing heat, choose fast-growing arugula and leaf lettuce, rather than slower-maturing, head-forming greens, such as radicchio and romaine.
Mosquitoes start multiplying as the weather grows warmer. Eliminate mosquito breeding sites at your home by draining excess water from anywhere water stands or collects.
Turn on water features every few days to discourage mosquitoes from those areas, too.
There are some chemicals that can be sprinkled in water features to deter mosquitoes. Be sure to read the labels carefully to ensure the chemicals won’t harm birds, pets or beneficial insects that visit your garden.
A little maintenance will maintain your garden’s beauty. After azaleas, camellias and rhododendrons finish blooming, remove spent blooms. Take care not to damage the new growth just beneath them. Feed the plants with a fertilizer especially developed for lovers of acidic soil.
Now that the days are warmer, it is time to trim back winter freeze damage from perennials.
As lawns start to need more water, make sure your sprinklers are covering the entire lawn area equally. Scatter a dozen equal-sized, flat-bottomed cans throughout the area while you water; then measure the water in each can and adjust your sprinklers if necessary.
• The Green Thumb is a column by Tracy’s master gardeners. University of California-certified master gardeners answer questions from 9 a.m. to noon Tuesday, Wednesday and Thursday at 953-6112 or firstname.lastname@example.org.