Seedlings should never dry out, so water daily while they are small. Taper off as the plants get larger. New transplants also need frequent watering—every other day or so—until their roots become established. After that, how often you need to water depends on your soil, how humid your climate is, and how often it rains. Plants are begging for water when they wilt slightly in the heat of the day. Water slowly and deeply, so the water soaks in instead of running off into the street. To minimize evaporation, water in the early morning.