Never mow off more than the topmost third of a blade of grass at one time. Even if the lawn is overgrown, mow off just a third; then wait a few days and mow another third. Because each blade of grass provides food for the entire plant, continual scalping will compromise the health of the lawn. Some of its roots may die; it will be less able to withstand extremes of temperature, lack of water, and incursions by pests and diseases.

The optimum heights of various grasses differ. Under normal conditions, these heights are: Common Bermuda, hybrid Bermuda, and colonial bent grass: 1/2 to 1 inch Zoysia and centipede: 1 to 2 inches Perennial rye and St. Augustine: 1 1/2 to 2 inches Fine fescue: 1 1/2 to 2 1/2 inches Bahia, blue grass, and tall fescue: 2 to 3 inches Buffalo grass: 2 to 4 inches

Don't cut off more than the top third of a grass blade when you mow.  Leave the clippings to decompose on the lawn.

Warm-season grasses grow fastest in hot weather, cool-season grasses in spring. At the peak of the growing season, mowing may be needed more than once a week. At other times of year, every 2 weeks or even once a month may be enough.