The number on the mower deck does more to a lawn than almost anything else you control, and it's the setting most often chosen by eye, or simply inherited from wherever it was last left.
Every variety is bred to hold a particular range. A height that keeps one grass immaculate will strip another one back to the soil.
A height that keeps one grass immaculate will strip another one back to the soil.
The bermudas run low
TifTuf holds anywhere from half an inch up to two inches, which is a wide range for a bermuda. Celebration will take up to two. Tifway 419 sits lowest of the three, under an inch and a half.
Tifway is the one to plan around. Nimmer, who grow it, note that holding it properly means mowing at least twice a week in season, which is why it turns up so often on sports fields and golf courses. It's a superb surface when it's kept at its height. Worth knowing what that involves before you choose it.
The zoysias and centipede sit in the middle
EMPIRE and Palisades want one to two inches. Zeon will go lower and holds well around an inch. Centipede sits in the same one-to-two-inch band.
This is the comfortable middle of the range, and a standard rotary mower on a middling setting is already close to right for all of them.
St. Augustine stays high
This is the one that most often catches people out.
Palmetto should not go below three inches, and four is better in a shaded yard. Nimmer state it plainly: maintain at no less than three inches. Cobalt runs a little lower at two to two and a half. ProVista sits between them.
Set a deck to bermuda height and take a St. Augustine lawn over it and you'll scalp it. The blades are broad and the growing points sit higher up the plant than they do on a fine grass, so a low cut takes the part that regrows rather than only the tips.
The one-third rule
Whatever the variety, the standard guidance isn't to remove more than a third of the blade in a single cut.
A lawn that has got ahead of you while you were away comes back down over two or three mowings a few days apart rather than in one afternoon. It's a small amount of extra patience and it saves the lawn a considerable shock.
Measure what you're actually cutting at
Deck settings aren't always the height you end up with. Tire pressure, a worn deck and the setting number itself can all put you somewhere other than where you think you're.
It's worth checking once. Put the mower on a flat hard surface, measure from the ground to the bottom edge of the blade, and compare that with the number on the lever. Most people find they're cutting lower than they believed, and on a St. Augustine lawn that gap is the whole problem.
A sharp blade helps
A blunt blade tears the leaf rather than cutting it, and the difference is visible a day or two later as a whitish, frayed edge across the top of the lawn instead of a clean line.
Sharpening once a season is enough for most home mowers.
See the ranges before you choose
Every variety on our grasses page lists the range it wants, and the simulator there lets you move the mow height and see what each one looks like at the top and bottom of it.
It's worth a couple of minutes. The difference between a bermuda at half an inch and a St. Augustine at four isn't a small adjustment to the same picture.
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