The right way: Determine how much water a plant, flower bed or lawn needs (online guides can help), and then deliver it with as little waste as possible. (Which is to say: Standing over part of your garden with the hose may not do the trick.) "A good, basic overall tip that I always relay is that deep watering is best," Chace says. "It inspires plant roots to grow deeper into the earth, making them healthier and more drought-resistant. This is true for your rosebushes as well as your front lawn."
If you've goofed: Your plants will let you know—they'll wilt or their leaves will turn yellow. "If you mend your ways, chances are they'll recover," Chace says. The exception is extreme overwatering: Many garden plants can die in truly soggy soil—root systems can rot in as little as a day—and the only solution is to tear them out and start again.