Mowing height: why the numbers differ
Tall fescue, bermudagrass and St. Augustinegrass mowing heights from five states' extension sources, and where they overlap or disagree.
By LawnYear editorial team · Published · Updated Windows are read from the extension publications listed under Sources; the dates are approximate.
Approximate dates for your state. Check with your local cooperative extension office before you act.
Mowing height is the one task where the extension pages give a number you can check against a ruler, and the numbers are not the same everywhere.
Tall fescue. NC State gives 2.5 to 3.5 in across the year, with 3.5 in from June to August, and says to mow before it gets taller than 5 in in summer. The University of Georgia gives 2 to 3 in all year. Ohio State's 2007 calendar gives 2.5 to 3 in, while a 2025 Ohio State article on early spring lawn care advises a 3 to 4 in lawn. The Ohio calendar also gives 2 to 2.5 in for Kentucky bluegrass, perennial ryegrass and fine fescues.
Bermudagrass. NC State accepts 5/8 to 2.5 in, with most lawns kept at 1 to 2.5 in, and says mowing below 1 in needs a reel mower and level ground. Georgia gives 1 to 2 in for common bermudagrass and 1 to 1.5 in for hybrids. Texas gives 1 to 2 in. Clemson says to start the season at 1.25 to 1.5 in.
St. Augustinegrass. Three states cover it: the lawn is kept at 2 to 3 in in Georgia, 2 to 4 in in Texas, and 2.5 to 4 in in South Carolina, where Clemson calls that range ideal depending on site and management. Clemson also says to cut down to 2 to 2.5 in just before spring green-up, then add 1/2 to 1 in once nights fall below 70 F.
Within each grass the ranges overlap from state to state, and the biggest gaps are between grasses: the St. Augustinegrass numbers sit above the bermudagrass numbers in every state that gives both. The one direct disagreement in these sources is Ohio's, where the 2007 calendar and the 2025 article give different numbers for the lawn; the sources do not say which supersedes the other.
Some rules recur. Georgia, Texas and Ohio all say not to remove more than a third of the leaf or blade at once, and Georgia says to raise the height 1/2 in in hot weather. NC State says to raise bermudagrass 1/2 in before frost.
How we read the sources: where a post sets states or grasses side by side, the comparison is ours, made by reading the extension pages next to each other. Every number comes from the page named.