Start mowing your lawn when the ground is dry and the grass is long enough to require cutting. Cut at the proper height for your type of grass that you have. Avoid mowing too low. Grass cut too short allows sunlight to reach soil, encouraging weed seeds to germinate. It also favors shallow root development, which makes the lawn more easily susceptible to drought stress. Follow the chart below depending on the type of lawn:
Bahia: 2.5 to 4 inches
Bermuda: 0.5 to 2.5 inches
Buffalo: 1.5 to 4 inches
Centipede: 1 to 2.5 inches
Kikuyu grass: 1 to 1.5 inches
St. Augustine: 1 to 3 inches
Zoysia: 0.5 to 3 inches