How Often to Mow St. Augustine Grass in Houston: A Month-by-Month Guide
St. Augustine is the default grass in most Houston yards for a reason. It handles our humidity, tolerates the shade under mature live oaks, and stays green for most of the year. It also grows fast enough from March through November that mowing is the single biggest part of keeping it healthy. Here is the rhythm that works across the Houston area, whether you are on the heavy clay in Katy or closer to the coast in League City.
The one rule that matters more than the calendar
Never remove more than a third of the blade in a single mow. St. Augustine spreads by stolons that run along the surface, and the blade is where the plant stores its energy. Scalp it and you stress the whole lawn at once: it thins, the soil shows, and Bermuda and weeds move into the gaps.
Keep the deck between 2.5 and 4 inches. Go taller in shade and taller in the worst of summer. If the lawn looks ragged the day after a mow, the blade needs sharpening; a dull blade tears St. Augustine instead of cutting it, and the torn tips brown within a day.
March and April: green-up
Wait for the lawn to green up on its own before the first real mow. In most Houston neighborhoods that is early-to-mid March. Set the deck on the low end of the range for the first cut to clear winter debris, then raise it back up. Growth is still slow, so every 10 to 14 days is usually enough.
May and June: the growth machine turns on
Warm nights and regular rain push St. Augustine hard. Weekly mowing becomes the baseline, and skipping a week usually means breaking the one-third rule on the next cut. If spring rains stack up and the yard is too wet to mow, cut as soon as it firms up rather than waiting for the schedule.
July and August: heat management
Growth stays strong if the lawn is watered, but the job changes: now you are protecting the grass from heat stress. Raise the deck toward 4 inches. The extra blade shades the soil, holds moisture, and keeps roots cooler. Mow in the morning or evening when you can, and never mow a drought-stressed lawn in the afternoon sun.
September and October: slow down and watch for circles
Growth eases off and you can stretch back to every 10 days or so. This is also Large Patch season. When nights cool but humidity stays, brown circles a few feet wide can show up almost overnight. Mowing will not fix it, and bagging clippings from the affected area helps keep it from spreading. If circles are appearing across the yard, it is worth having someone look at it before fall fertilizing.
November through February: the quiet months
Most years there is a last real mow in mid-to-late November. Houston winters are mild, so the lawn rarely goes fully dormant; it just stops growing. An occasional tidy-up cut on a warm stretch is fine. The more useful winter job is keeping fallen leaves from matting on the grass, since a wet leaf layer smothers St. Augustine.
Mulch the clippings or bag them?
Mulch, almost always. Clippings break down fast and return nitrogen to the lawn, and with weekly mowing they disappear into the canopy. Bag only when the grass got away from you and the clumps would smother the lawn, or when you are mowing over a fungus-affected area.
Common questions
Do I need to water right after mowing? No. Water on your normal schedule, deeply and infrequently, in the early morning. Mowing does not change what the roots need.
Why does my lawn look brown right after mowing? Either the blade is dull and tearing the grass, or the deck dropped below the healthy range and you are cutting into stems. Sharpen first; it fixes it more often than people expect.
Bermuda is creeping into my St. Augustine. Does mowing height matter? Yes. Bermuda loves short lawns and full sun. Keeping St. Augustine at 3.5 to 4 inches shades Bermuda out and slows the takeover.