Frequent watering can be too much of a good thing for a lawn. For example, warm-season grasses, such as Bermuda and zoysia grasses, need 1/2 inch to 3/4 inch of water as infrequently as every one to three weeks. Cool-season grasses, such as perennial ryegrass and Kentucky bluegrass, need watering every four or five days. Too much water interferes with healthy grass growth and makes the lawn susceptible to pests and diseases.