Warm-season grass • USDA Zone 9

St. Augustine Grass Lawn Care Schedule — USDA Zone 9

St. Augustine is a warm-season grass with broad, coarse blades that handles shade and coastal salt better than other Southern turfs. It is not cold-hardy, so it's grown in the warmest zones, where it makes a thick, blue-green lawn that spreads by above-ground runners. This schedule is tuned for USDA hardiness zone 9 — warm, nearly frost-free winters (average lows around 20 to 30°F). Green-up, fertilizing, and pre-emergent timing all shift with your winter low temperatures, so the windows below are tuned for this zone.

Type: Warm-season
Mowing height: 3–4″
Nitrogen budget: 2–4 lbs N / 1,000 sq ft / yr
Growth habit: Spreading (self-repairs)
Shade tolerance: High
Drought tolerance: Moderate
Traffic tolerance: Low
Winter low: average lows around 20 to 30°F

Different zone?

See the St. Augustine schedule for another USDA hardiness zone, or the full St. Augustine care guide.

Key care windows for Zone 9

Timing windows are flexible (early / mid / late) and tuned to Zone 9's season — soil temperature and your local weather should always have the final say.

early January to early February

Spring pre-emergent (crabgrass)

Apply a pre-emergent herbicide as soil temperatures approach 55°F to stop crabgrass and other summer weeds before they germinate. A second application 6–8 weeks later extends control through the season.

Don't apply a pre-emergent if you plan to seed — it blocks grass seed too. Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.

early January to mid-February

Spring green-up & first mow

As soil temperatures reach about 55°F the lawn breaks dormancy and greens up. Once it's about half green, mow low to clear dormant material and let sunlight reach the crowns. Don't fertilize until it's at least 80% green.

mid-March to early April

First feeding

Make the first fertilizer application 2–4 weeks after full green-up, once the lawn is actively growing. Feed about 2–4 lbs of nitrogen per 1,000 sq ft per year across the warm months. An iron supplement deepens color without forcing the excess top growth that heavy nitrogen would.

Several weed killers that are fine on other lawns will damage St. Augustine — confirm the label lists it by name before spraying. Keep nitrogen at or below ~1 lb per 1,000 sq ft per feeding. Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.

late March to mid-May

Aeration & dethatching

Core-aerate (and dethatch if the thatch layer is over about ½") during the peak growing season, when warm-season turf recovers fastest. Avoid aerating dormant or drought-stressed turf.

late April to mid-July

Summer feeding program

Summer is the warm-season growth peak. Feed about 2–4 lbs of nitrogen per 1,000 sq ft per year across the warm months. An iron supplement deepens color without forcing the excess top growth that heavy nitrogen would. Spread the annual budget across the season rather than applying it all at once.

Never exceed ~1 lb of nitrogen per 1,000 sq ft in a single feeding. Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.

late April to mid-July

Summer weed & pest watch

Spot-treat broadleaf weeds during active growth, never on drought-stressed turf. Watch for insect and disease pressure in hot, humid weather and treat problem areas rather than the whole lawn.

mid-October to early November

Final feeding & soil test

Give a final feeding in early fall, then stop nitrogen — late-season nitrogen pushes tender growth into frost. Fall is also the best time to take a soil test so amendments are ready before spring.

Stop nitrogen about 6 weeks before your first expected frost. Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.

early November to late November

Fall pre-emergent (winter weeds)

A fall pre-emergent applied before soil cools below about 70°F controls winter annual weeds like Poa annua and henbit.

Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.

mid-December to late December

Winter dormancy

Expect a brown, dormant lawn from first frost until spring green-up. Hold off on fertilizer and pre-emergent. A light watering during extended winter drought helps prevent desiccation.

Month-by-month schedule

A quick at-a-glance plan for St. Augustine grass in USDA zone 9, month by month.

Month	Season	What to do
January	Winter	Watch for green-up; do the first low mow to clear winter material. Apply crabgrass pre-emergent before soil reaches ~55°F.
February	Winter	Watch for green-up; do the first low mow to clear winter material. Apply crabgrass pre-emergent before soil reaches ~55°F.
March	Spring	Make the first feeding once the lawn is fully green and growing. Core-aerate during peak growth; dethatch if thatch is heavy. Mow at 3–4" and water deeply as needed.
April	Spring	Make the first feeding once the lawn is fully green and growing. Core-aerate during peak growth; dethatch if thatch is heavy. Continue the summer feeding program on schedule. Spot-treat weeds and scout for pests; water deeply in heat. Mow at 3–4" and water deeply as needed.
May	Spring	Core-aerate during peak growth; dethatch if thatch is heavy. Continue the summer feeding program on schedule. Spot-treat weeds and scout for pests; water deeply in heat. Mow at 3–4" and water deeply as needed.
June	Summer	Continue the summer feeding program on schedule. Spot-treat weeds and scout for pests; water deeply in heat. Mow at 3–4" and water deeply as needed.
July	Summer	Continue the summer feeding program on schedule. Spot-treat weeds and scout for pests; water deeply in heat. Mow at 3–4" and water deeply as needed.
August	Summer	Steady-state: mow at 3–4" and water deeply about 1" per week including rain.
September	Fall	Steady-state: mow at 3–4" and water deeply about 1" per week including rain.
October	Fall	Make the final feeding of the year; take a soil test. Mow at 3–4" and water deeply as needed.
November	Fall	Apply a fall pre-emergent for winter weeds before soil cools. Make the final feeding of the year; take a soil test. Mow at 3–4" and water deeply as needed.
December	Winter· dormant	Lawn is dormant — no feeding; water lightly only in extended drought.

St. Augustine at a glance

Best shade tolerance of the warm-season grasses
Thrives in heat, humidity, and coastal conditions
Spreads quickly by stolons to fill in
Not cold-hardy — limited to the warmest zones
Prone to chinch bugs and gray leaf spot
Coarse texture; doesn't take heavy traffic

For the full St. Augustine mowing, watering, fertilizing, and weed-control guide that applies in every zone, see the complete St. Augustine lawn care schedule.

Safety first

Several weed killers that are fine on other lawns will damage St. Augustine — confirm the label lists it by name before spraying. Keep nitrogen at or below ~1 lb per 1,000 sq ft per feeding.