Mow Kentucky bluegrass and fine fescue lawns at 2 to 3 inches. Tall fescue lawns should be mowed at 3 inches. Proper mowing also means mowing at regular intervals. Scalping the lawn can shock it, making it more susceptible to stress. Lawn mowers should be kept sharp.
Dull mowers leave wounds on the grass blade that serve as a point of entry for diseases.
Leaf spot is especially encouraged by dull mower injury. While this is an effective means to survive drought, summer dormancy may result in extensive injury from insects and disease, and encourages weed invasion. Remember, it is a vigorous, healthy lawn that best resistant to pests. In the early summer, lawns should be watered when signs of wilt appear. Water the lawn thoroughly with about 1-inch of water.