How to Care for St. Augustine Grass in Florida

If you live in St. Augustine, Nocatee, World Golf Village, Silverleaf, or almost anywhere else in St. Johns County, there’s a good chance your lawn is St. Augustinegrass. It’s the default turf for most new-build communities in North Florida — and for good reason: it tolerates heat, holds up well in sandy soil, and spreads quickly to fill in bare spots. But it isn’t maintenance-free. Mow it wrong, water it wrong, or ignore the wrong pest at the wrong time, and it can thin out fast.

Here’s what actually keeps St. Augustinegrass healthy through a Florida year.

Mowing Height & Frequency

St. Augustinegrass wants to be mowed taller than most northern lawn types — generally 3.5–4 inches. Cutting it shorter weakens the root system, invites weeds, and makes it far more vulnerable to drought stress and disease.

• Never remove more than one-third of the blade height in a single mow — if it’s gotten too tall, bring it down gradually over two or three cuts
• During peak growing season (roughly April–September in North Florida) that usually means mowing weekly
• In cooler months, growth slows dramatically — every 2–3 weeks is often enough
• Keep mower blades sharp; a dull blade tears grass instead of cutting it, leaving ragged, brown-tipped edges

Watering

St. Augustinegrass generally needs about 3/4 to 1 inch of water per week, including rainfall — applied deeply and infrequently rather than a little every day. Frequent shallow watering trains roots to stay near the surface, which makes the lawn less drought-tolerant, not more.

• Water early in the morning (roughly 4–10am) so grass isn’t sitting wet overnight, which invites fungal disease
• Watch the grass itself for signs it needs water — a blue-gray tint or blades that don’t spring back after being walked on both mean it’s time

Read our full watering guide — how often and why timing matters

Fertilization

St. Augustinegrass benefits from a light, consistent fertilization schedule rather than one heavy application. A general rhythm for North Florida:

• Spring (April–May): first feeding once the lawn has fully greened up after winter
• Summer: a light feeding to sustain color and density through peak growth
• Fall (September–October): a final feeding before growth slows for winter
• Avoid heavy nitrogen applications in late fall/winter — it encourages tender growth right when the lawn is most vulnerable to cold damage and disease

A soil test is the most reliable way to know exactly what your lawn needs rather than guessing — your county extension office can usually point you to affordable testing.

Common Pests: Chinch Bugs

Chinch bugs are the single most common pest problem in Florida St. Augustinegrass. They thrive in hot, dry, sunny areas of the lawn and cause irregular patches of yellowing, drought-stressed-looking grass that don’t improve with watering — that last part is the giveaway that it’s bugs, not thirst.

• Damage typically shows up first in the hottest, sunniest parts of the yard, often near driveways or sidewalks that radiate heat
• Left untreated, chinch bug damage spreads and can kill large sections of lawn
• Population peaks are usually late spring through summer

Read our full guide on identifying chinch bugs

Common Disease: Large Patch

Large patch (sometimes still called brown patch) is a fungal disease that shows up during cooler, wet periods — typically fall through spring in Florida. It causes circular patches of brown or yellow grass, often several feet across, with the blades pulling loose easily at the base when tugged.

Good cultural practices — correct mowing height, avoiding overwatering, and not over-fertilizing with nitrogen in cool months — go a long way toward preventing it in the first place.

Shade Tolerance

Not all St. Augustinegrass is equally shade-tolerant. ‘Floratam,’ the most widely sold variety, actually handles shade poorly and will thin out under heavy tree canopy. If large sections of your yard stay shaded most of the day, a more shade-tolerant cultivar (like ‘Seville’ or ‘Palmetto’) will hold up dramatically better long-term.

Weed Control

A thick, healthy, correctly-mowed St. Augustinegrass lawn is naturally one of the best defenses against weeds — it simply doesn’t leave much open ground for weed seeds to establish. Pre-emergent treatments timed for early spring (before soil temperatures consistently hit the mid-60s°F) help catch summer weeds before they germinate.

Why weeds get so much harder to control by summer

When to Call a Professional

Diagnosing the difference between drought stress, chinch bugs, fungal disease, and simple mowing damage isn’t always obvious — and treating the wrong problem can waste time while the real issue keeps spreading. If your lawn has patches that aren’t responding to watering, or you’re not confident in what you’re looking at, it’s worth having someone take a look before it gets worse.