Use a Rain Gauge
Measure the rainfall with a rain gauge posted near the garden so you can tell when to water. The garden needs about one inch of rain per week from April to September.
Install Cages and Stakes
Put in plant stakes, peony cages, or other supports now, while the plants are still small and manageable. I use green wire cages -- they disappear into the landscape while keeping my plants standing tall.
Fertilize Spring Bloomers
Fertilize those early-spring bloomers that have finished flowering for the season, but are gathering nutrients to store up for next year's show, such as forsythias and lilacs. When their bloom is finished, most likely by the end of the month, it's the perfect time to prune them, before they set buds for next year's flowers.
Plant Heat-Loving Veggies
You can plant corn, green beans, squashes, and melons when the soil temperature is about 60F. An easy way to test the temperature is by walking barefoot on the soil. If you can walk comfortably, the soil is warm enough to plant corn.
Deadhead Rhodies and Azaleas
Deadhead rhododendrons and azaleas when they have finished blooming. Cut or pinch off the spent flowers by snapping off the trusses with your fingers so you won't damage the latent buds just below them.