Our mowing height guide gives a number for each grass, and that number is right for the bulk of the growing season. But a lawn in Jefferson County goes through a real winter, a dry spring, a brutal summer and a wet fall, and the deck should move a little with it. Here is how we set it.
Why height changes matter
Leaf area is how the plant makes food. A taller cut means deeper roots, more shade on the soil, less evaporation and fewer weed seeds germinating. A shorter cut means faster warm-up in spring, a tighter look, and more stress in heat. Neither is right all year. The trick is moving between them slowly enough that the grass never gets scalped.
Late winter: the one time to go low
In late February or early March, before green-up, warm-season lawns are still dormant and the top is dead, brown leaf. Dropping the cut by about a half inch, once, and bagging the clippings removes that dead material, lets sun hit the crowns, and speeds green-up by a week or two. It also takes down winter weeds before they seed.
Do this once. Do not scalp centipede down to the dirt the way people do with Bermuda on golf courses. Centipede's stolons run on the surface and a hard scalp exposes them to a late freeze. A half inch below your summer height is enough. Our spring green-up sequence covers the rest of the timing.
Spring: back to normal, gradually
Once the lawn is green and growing, in April for most of the Big Bend, bring the height back up to the standard for your grass over two or three mowings. Centipede settles at one and a half to two inches, St. Augustine at three to four, Bermuda at one to two, Zoysia at one and a half to two and a half. Mow often enough that you never take more than a third of the blade in one pass; in a wet April that can mean every five days.
Summer: raise it and leave it
June through September is where most lawns around Monticello get hurt. Heat, drought in the gaps between storms, chinch bugs and disease all hit harder on short grass. We raise the deck a quarter to a half inch above the spring setting and hold it there:
- Centipede: two inches, or a little above under trees.
- St. Augustine: four inches, the top of its range, especially in shade.
- Bermuda: two inches for a home lawn. Lower is possible with a reel mower and daily attention; most people do not have either.
- Zoysia: two to two and a half inches.
The taller canopy shades the soil and buys the lawn a couple of days between rains. It also hides the ragged edge of a lawn that could not be mowed on time because it rained for a week straight. Our post on summer heat stress goes deeper.
Fall: hold, then taper
Keep the summer height through September. Growth slows in October and the lawn needs fewer cuts, but do not drop the height to compensate; a lawn going into dormancy taller has more stored energy and more protection for the crowns. One thing to avoid is letting it get shaggy in a wet October and then taking it all off at once. That single hard cut is what sets up large patch in centipede and St. Augustine. Mow lightly and often until growth stops.
Winter: mow the weeds, not the grass
Once the lawn is fully dormant, usually after the first hard freeze in November or December, the grass is not growing and does not need cutting. What does grow is winter weeds: poa annua, henbit, chickweed, wild garlic. A pass every few weeks at the summer height keeps them from seeding and keeps the lawn looking tidy without touching the dormant turf. If you overseeded with ryegrass, that is a different schedule.
The exceptions
- Drought. Any time the lawn is stressed for water, raise the cut and skip a mowing rather than cutting dry, wilted grass.
- Shade. Under oaks and pines, run every grass at the top of its range all year. Shade grass needs the leaf.
- New sod. Leave it alone until it is rooted, then start at the summer height and work down. Our new sod guide covers it.
- After a freeze. Do not cut frost-damaged grass until it has recovered. The brown leaf is protecting what is underneath.
FAQ
Does the height on my mower dial match the actual cut?
Rarely. Set the mower on a flat driveway and measure from the pavement to the blade edge. Most dials are off by a quarter inch or more.
Should I lower the height before a hurricane?
No. Height does not matter to a storm. Cleanup afterward is what matters.
My lawn service cuts at the same height all year. Is that a problem?
If the height is at the top of the range, it is fine. If it is short all year, the lawn is being stressed every summer.
Do you adjust height by yard?
Yes. It is part of any maintenance plan we set up; a shady St. Augustine yard and a sunny centipede one get different settings.
If you'd like a crew that pays attention to the deck setting and not just the schedule, get in touch. We mow yards around Monticello and Drifton every week through the season.