Blog Post | LocalLandscape

Fall in Fulshear doesn't arrive all at once. What you do in the stretch from early October until the first frost, has a lot to do with how your lawn looks next spring. Here is a practical fall lawn care guide for warm-season grass in Fulshear and the rest of Fort Bend County, based on Texas A&M AgriLife Extension recommendations.

Keep Mowing Until the Grass Stops Growing

As nights cool off, St. Augustine, Bermuda and Zoysia all slow down, but don't park the mower yet. AgriLife's advice for St. Augustine from September on is to keep up your normal mowing until the grass goes dormant and no longer needs it.

What changes is how often you mow. AgriLife ties mowing frequency to the one-third rule: never remove more than one-third of the leaf height in a single cut. For example, if you mow at 3 inches, cut again before the grass reaches about 4½ inches. In early fall that may still mean weekly mowing. Once growth slows, every other week is often enough.

Fall mowing heights

St. Augustine: AgriLife publications give slightly different ranges: 2 to 4 inches in one fact sheet, 2½ to 3 inches (3 to 3½ inches in shade) in another, and 2 to 3 inches in the large patch guide. A good rule of thumb from AgriLife is to set your mower at its highest setting or one notch below. Taller grass shades out weeds and grows deeper roots.
Bermuda: 1 to 2 inches for home lawns with a rotary mower.
Zoysia: 1 to 2 inches for home lawns with a rotary mower.

Don't lower the deck in fall to "get one more cut out of it." AgriLife lists a low mowing height as one of the conditions that promote large patch disease, and St. Augustine has no underground rhizomes to recover from scalping the way Bermuda does. Keep your blades sharp, too.

Fall Fertilizing: Less Nitrogen, and Stop Early

This is the fall mistake that causes the most trouble in St. Augustine lawns. AgriLife lists over-fertilizing late in the fall as one of the main conditions that promote large patch, and warns that too much fall nitrogen can also increase winter kill.

AgriLife's guidance for St. Augustine:

Make your last regular nitrogen feeding at least 4 to 6 weeks before your area's average first frost.
If you fertilize at that point, use a low-nitrogen, high-potassium fertilizer, at no more than ½ pound of nitrogen per 1,000 square feet.
Don't fertilize St. Augustine from December through February unless the lawn has been overseeded.
Get a soil test instead of guessing.

Using the Houston-area frost averages below, that means the last feeding should go down somewhere between mid-October and early November. Since it's already October, if you haven't fertilized yet, the safest choice for many St. Augustine lawns is to skip it this fall.

Cut Back on Watering

Your lawn needs far less water now than in August. AgriLife suggests turning off automatic sprinklers in spring and fall and watering by hand only when the lawn needs it. Too much fall watering wastes water and makes the lawn more likely to get large patch.

Water only when you see drought stress: a dull bluish color, rolled or folded leaves, or footprints that stay pressed into the grass.
When you do water, wet the soil about 6 inches deep, then wait until the lawn shows stress again.
Water in the early morning (AgriLife suggests 3 a.m. to 9 a.m.). Evening watering keeps the grass wet overnight, which encourages disease.
Even when the lawn is dormant, it may need an occasional drink during warm, dry, windy spells.

Watch for Large Patch (Brown Patch) in Cool, Wet Weather

Many homeowners call it "brown patch." On St. Augustine and Zoysia, AgriLife calls it large patch. It's caused by the same fungus, Rhizoctonia solani, which causes brown patch on cool-season grasses. AgriLife calls it the most chronic disease of St. Augustine and Zoysia in Texas.

When: the fungus thrives once temperatures drop below about 70°F and the soil is wet. In Texas, fall outbreaks typically start in October and November.
What it looks like: circular, discolored patches with orange or yellow outer edges.
Quick field test: leaf blades at the edge of a patch pull easily away from the runner.
What helps: good drainage, deep but infrequent early-morning watering, less thatch, balanced fertilizer and the right mowing height.

The fungus can travel on equipment while it's active. AgriLife discourages mowing infected areas until the disease stops spreading and advises against returning clippings to the lawn during active disease. If you spot large patch, mow those areas last, bag the clippings from them, and clean the mower deck afterward. Fungicides work best as prevention in fall, before symptoms appear. If you use one, choose a product labeled for home lawns and follow the label. Damaged grass usually won't fill back in until the following spring.

Mulch-Mow Light Leaf Fall

Texas A&M's Earth-Kind program calls mowing over leaves "probably the most efficient and easiest way" to handle them. A light layer of leaves can be shredded with the mower and left on the lawn, and a mulching mower works best. The pieces settle between the grass blades and release nutrients as they break down. If you have big trees and a thick blanket of leaves, rake or bag some of them for compost or flower-bed mulch so they don't smother the grass.

Dormancy and the First Frost in Fulshear

St. Augustine turns brown or off-color during winter dormancy. That's normal, not a sign the lawn is dead. In milder parts of Texas, warm-season grass may not go fully dormant every winter.

We couldn't find a published first-frost date specifically for Fulshear or Fort Bend County. The closest AgriLife figures come from Harris County: an average first freeze of November 30 at Bush Intercontinental and December 20 at Hobby. For homeowners west of Houston, plan for a first frost window of roughly late November through December, and remember any given year can be earlier or later. For a local estimate, call the Fort Bend County AgriLife Extension office in Rosenberg at 281-342-3034.

Need Help Keeping Up With the Mowing?

Fulshear Lawn Mowing Service is a veteran-owned business run by James Henderson. We offer lawn mowing and edging only, for homes in Fulshear, Katy, Richmond, Simonton and Brookshire. Mowing starts at $45 per visit (weekly, every other week, or a one-time cut), and edging is an add-on starting at $15 per visit. Call (832) 338-2926 or visit our Fulshear Lawn Mowing Service profile.

Fall Lawn Care in Fulshear: St. Augustine Guide