Lawn Care Schedule for St. Augustine Grass: A Complete Seasonal Guide

St. Augustine grass is one of the most popular warm-season turfgrasses in the southern United States, prized for its thick, carpet-like texture & excellent shade tolerance. Whether you have been maintaining a St. Augustine lawn for years or just moved into a home with an established yard, understanding the proper care schedule is essential for keeping your grass healthy, green, & resilient throughout the year.

Unlike cool-season grasses that thrive in northern climates, St. Augustine grass (Stenotaphrum secundatum) follows a warm-season growth pattern. It greens up in spring, grows vigorously through summer, & goes dormant in fall & winter. This growth cycle means your lawn care tasks need to shift with the seasons to match what the grass actually needs at any given time.

This comprehensive guide breaks down a practical, season-by-season lawn care schedule for St. Augustine grass. You will find actionable steps for mowing, fertilizing, watering, weed control, pest management, & disease prevention — everything you need to maintain a lush, healthy lawn. For more background on this grass variety, check out our complete guide to St. Augustine grass.

Spring Lawn Care for St. Augustine Grass (March Through May)

Spring is the wake-up call for your St. Augustine lawn. As soil temperatures climb above 55°F, the grass breaks dormancy & begins its active growth phase. This is arguably the most critical season for setting the tone for the rest of the year. A well-executed spring routine helps your lawn recover from winter stress & build the density it needs to crowd out weeds.

First Mow & Mowing Height

Your first mow of the season should happen once the grass reaches about 3 to 3.5 inches in height. Set your mower blade to 2.5 to 3 inches for this initial cut, then gradually raise it to the ideal maintenance height of 3 to 4 inches. St. Augustine grass performs best when kept slightly taller than many other warm-season grasses, as the extra leaf surface supports photosynthesis & shades the soil to reduce weed germination.

Always follow the one-third rule: never remove more than one-third of the grass blade in a single mowing. Cutting too short stresses the grass, exposes the soil to sunlight, & invites weeds like crabgrass & dallisgrass. For more details, read our mowing tips for a healthier lawn.

Spring Fertilization

Wait until your lawn has fully greened up & you have mowed at least twice before applying fertilizer. This typically occurs in mid to late spring. Applying nitrogen too early feeds weeds rather than your still-dormant grass.

Recommended products:

• A balanced, slow-release granular fertilizer with an NPK ratio around 15-5-10 or 16-4-8
• Scotts Turf Builder Southern Lawn Food
• Lesco Professional Starter Fertilizer for new sod or plugs

Apply approximately 1 pound of nitrogen per 1,000 square feet during this spring feeding. Use a broadcast spreader for even coverage & water the lawn lightly afterward to activate the granules. Visit our lawn fertilization guide for more in-depth nutrient advice.

Pre-Emergent Weed Control

If you did not apply a pre-emergent herbicide in late winter, early spring is your last window to prevent summer annual weeds like crabgrass, goosegrass, & sandbur. Look for products containing prodiamine or dithiopyr as the active ingredient. Apply according to label directions & water in thoroughly.

For existing broadleaf weeds that have already emerged, use a post-emergent herbicide labeled as safe for St. Augustine grass. Products containing atrazine are commonly recommended, but always check the label carefully, as St. Augustine is more sensitive to certain herbicides than other turf types.

Watering & Irrigation Checks

As temperatures rise, begin transitioning to a regular watering schedule. St. Augustine grass needs about 1 to 1.5 inches of water per week during active growth, whether from rainfall or irrigation. In spring, natural rainfall may be sufficient in many regions, but supplement during dry spells.

Spring is also the ideal time to inspect your irrigation system. Run each zone & check for broken sprinkler heads, clogged nozzles, & uneven coverage patterns. Proper irrigation setup now prevents brown spots & drought stress later in the summer.

Summer Lawn Care for St. Augustine Grass (June Through August)

Summer is peak growing season for St. Augustine grass. The combination of heat, humidity, & long days means your lawn is growing rapidly & demanding more attention than any other time of year. However, this is also when the grass faces the most stress from heat, drought, pests, & disease.

Mowing Frequency & Height

During summer, you may need to mow your St. Augustine lawn every 5 to 7 days to maintain the recommended 3 to 4 inch height. Keeping the grass on the taller side during hot months is crucial — taller blades shade the soil, reduce moisture evaporation, & protect the crown of the plant from heat stress.

Keep your mower blades sharp. Dull blades tear the grass rather than cutting cleanly, leaving ragged edges that turn brown & make the lawn more susceptible to disease. Sharpen or replace blades at least once during the summer season.

Summer Fertilization

Feed your St. Augustine lawn every 6 to 8 weeks during summer with a slow-release nitrogen fertilizer. A product with an NPK ratio of 15-5-10 or similar works well. Apply at a rate of 0.5 to 1 pound of nitrogen per 1,000 square feet per application.

Avoid fertilizing during extreme heat or drought conditions, as this can burn the grass. Water the fertilizer in immediately after application & try to schedule feedings for early morning or late afternoon when temperatures are slightly lower.

Recommended summer fertilizers:

• Milorganite Slow-Release Nitrogen Fertilizer
• Scotts Turf Builder SummerGuard (includes insect control)
• Andersons Professional PGF Balanced 10-10-10

Deep & Infrequent Watering

Water deeply but infrequently to encourage deep root growth. Aim for 1 to 1.5 inches of water per week, applied in 2 to 3 sessions rather than daily light sprinklings. The best time to water is early morning, between 4 AM & 8 AM, when evaporation is minimal & fungal diseases are less likely to develop.

Watch for signs of water stress: if footprints remain visible on the grass for several minutes after walking, or if the blades take on a bluish-gray tint, your lawn needs water immediately. For more irrigation strategies, see our complete watering guide.

Pest & Disease Monitoring

Summer is prime time for two major St. Augustine grass problems: chinch bugs & brown patch disease.

Chinch bugs are the most destructive insect pest of St. Augustine grass. They are tiny, black insects with white wings that feed on grass sap, causing yellowing & browning patches, especially in sunny areas near sidewalks & driveways. Part the grass at the border between healthy & damaged areas to spot them. If you find 20 or more chinch bugs per square foot, treat with a lawn insecticide containing bifenthrin or imidacloprid.

Brown patch (caused by the fungus Rhizoctonia solani) appears as circular brown patches that expand outward, often with a dark ring at the edge. It thrives in warm, humid conditions with excessive moisture. Reduce evening watering, improve air circulation, & apply a preventive fungicide containing azoxystrobin or propiconazole if the disease recurs annually.

Gray leaf spot is another fungal disease to watch for. It appears as small, oval, gray-green spots on the blades. Avoid over-fertilizing with nitrogen during humid periods, as this promotes the disease.

Fall Lawn Care for St. Augustine Grass (September Through November)

As daylight hours shorten & temperatures cool, St. Augustine grass begins to slow its growth & prepare for dormancy. Fall lawn care focuses on strengthening the root system, preventing winter weeds, & preparing the lawn for its dormant period.

Adjusting Mowing Practices

Gradually reduce mowing frequency as growth slows. Continue to maintain a height of 3 to 4 inches until the grass stops growing. Your final mow of the season can drop the height slightly to about 2.5 to 3 inches, which helps reduce the habitat for pests & disease over winter.

Leave grass clippings on the lawn during fall mowing (as you should during other seasons). They decompose quickly & return valuable nutrients to the soil. This practice, known as "grasscycling," can supply up to 25 percent of your lawn's annual nitrogen needs.

Fall Fertilization & Potassium Boost

Apply a fall fertilizer about 6 weeks before your area's average first frost date. This feeding should be lower in nitrogen & higher in potassium compared to summer applications. Potassium strengthens cell walls & improves cold tolerance, helping the grass survive winter stress.

Look for a fertilizer with an NPK ratio like 5-10-30 or a winterizer formula specifically designed for warm-season grasses. Apply at a rate of about 1 pound of potassium per 1,000 square feet.

Recommended fall products:

• Scotts Turf Builder WinterGuard
• Superior Nitrogen & Potash 0-0-25 Liquid Fertilizer
• Lesco 0-0-24 Turf Fertilizer

Pre-Emergent Herbicide for Winter Weeds

Fall is the time to apply a pre-emergent herbicide to prevent cool-season annual weeds like annual bluegrass (poa annua), henbit, chickweed, & annual ryegrass. Apply the pre-emergent when soil temperatures drop to around 70°F, which typically corresponds to early to mid-fall in most St. Augustine growing regions.

Products containing prodiamine (Barricade) or pendimethalin (Pendulum) are effective choices. Water the herbicide into the soil after application to activate the chemical barrier. Avoid aerating or dethatching after application, as this breaks the barrier & reduces effectiveness.

Aeration & Dethatching

If your St. Augustine lawn has developed a thatch layer thicker than half an inch, early fall is the best time to address it. Thatch — the layer of dead & living organic matter between the soil surface & the green grass blades — prevents water, nutrients, & air from reaching the roots.

For St. Augustine grass, use a vertical mower (verticutter) or a dethatching rake rather than a power rake, which can be too aggressive. Core aeration can also help relieve soil compaction & improve thatch breakdown. Schedule these tasks at least 4 to 6 weeks before the first expected frost so the grass has time to recover. Read our lawn aeration guide for step-by-step instructions.

Winter Lawn Care for St. Augustine Grass (December Through February)

St. Augustine grass enters dormancy when soil temperatures drop below 55°F. During this period, the grass turns brown & stops growing, but it is still alive & needs basic care to emerge healthy in spring.

Dormant Lawn Maintenance

Reduce watering significantly during dormancy. The grass needs only about 0.5 inches of water per week to prevent the crown from drying out. In many regions, natural rainfall provides enough moisture. However, during extended dry spells in winter, a light watering every two weeks helps protect the root system.

Avoid walking on dormant St. Augustine grass as much as possible. The grass cannot recover from damage while dormant, & heavy foot traffic can compact the soil & create bare patches that weeds will colonize in spring.

Weed Control During Dormancy

Winter weeds can be a nuisance in dormant St. Augustine lawns. Since the grass is brown, green weeds like henbit, chickweed, & poa annua stand out prominently. You can apply post-emergent herbicides labeled for use on dormant St. Augustine grass during this period. Products containing 2,4-D, MCPP, & dicamba are generally safe when the grass is fully dormant, but avoid application during spring green-up, as the grass is extremely sensitive to herbicides during that transition.

Equipment Maintenance & Planning

Winter is the perfect time to service your lawn care equipment. Sharpen mower blades, change the oil, replace air filters, & clean undercarriage debris. Order any supplies you will need for spring — fertilizer, pre-emergent herbicide, grass plugs for bare spots — so you are ready to act as soon as the lawn greens up.

This is also a great time to test your soil. A soil test reveals pH levels & nutrient deficiencies so you can tailor your spring fertilization plan accordingly. Most cooperative extension offices offer affordable soil testing services, & results typically arrive within 2 to 3 weeks.

Essential Tools & Products for Year-Round St. Augustine Lawn Care

Having the right tools on hand makes following your lawn care schedule significantly easier. Here is a checklist of essentials for maintaining St. Augustine grass:

Mowing Equipment

• Rotary mower — St. Augustine grass is best cut with a rotary mower rather than a reel mower, as the coarse blades & stolons can jam reel-type units
• Mulching blade or kit — enables grasscycling by finely chopping clippings
• Blade sharpener or replacement blades — for clean cuts that reduce disease risk

Fertilization & Soil Care

• Broadcast spreader — for even application of granular fertilizer & herbicide
• Soil test kit — to determine pH & nutrient levels (target pH of 6.0 to 7.5 for St. Augustine)
• Slow-release nitrogen fertilizer — the backbone of your feeding program
• Potassium-rich winterizer — for fall cold-hardiness preparation

Weed & Pest Control

• Pre-emergent herbicide — prodiamine or pendimethalin based
• Post-emergent herbicide — atrazine or 2,4-D based, labeled safe for St. Augustine
• Insecticide — bifenthrin or imidacloprid for chinch bugs & grubs
• Fungicide — azoxystrobin or propiconazole for brown patch & gray leaf spot

Watering & Aeration

• Oscillating or rotary sprinklers — if you do not have an in-ground irrigation system
• Rain gauge or soil moisture meter — to measure actual water delivery
• Core aerator (rental or purchase) — for relieving compaction
• Dethatching rake or verticutter — for thatch management

For more recommendations on choosing the right equipment, browse our essential lawn care tools guide.

Frequently Asked Questions About St. Augustine Grass Care

How often should I water St. Augustine grass?

During the active growing season (spring through early fall), St. Augustine grass needs approximately 1 to 1.5 inches of water per week. This can come from rainfall, irrigation, or a combination of both. Water deeply 2 to 3 times per week rather than lightly every day. During winter dormancy, reduce watering to about 0.5 inches per week or rely on natural rainfall. Always water in the early morning to minimize evaporation & reduce the risk of fungal diseases.

What is the best fertilizer for St. Augustine grass?

The best fertilizer for St. Augustine grass is a slow-release, nitrogen-rich formula with an NPK ratio around 15-5-10 or 16-4-8 during the growing season. Slow-release nitrogen feeds the grass steadily over 6 to 8 weeks, reducing the risk of fertilizer burn & excessive top growth. In fall, switch to a low-nitrogen, high-potassium fertilizer to improve winter hardiness. Organic options like Milorganite are also popular among St. Augustine lawn owners. Always base your fertilization plan on a soil test for the best results. See our warm-season grass fertilizer guide for detailed product comparisons.

Why is my St. Augustine grass turning yellow?

Yellowing in St. Augustine grass can be caused by several factors. The most common causes include iron chlorosis (iron deficiency, often in high-pH soils), nitrogen deficiency, chinch bug damage, overwatering, or fungal disease like take-all root rot. Iron chlorosis is particularly common in alkaline soils & can be corrected by applying chelated iron or iron sulfate. If the yellowing appears in patches near hardscapes, inspect for chinch bugs. A soil test is the most reliable way to diagnose nutrient-related yellowing.

How do I fix bare or thin spots in my St. Augustine lawn?

St. Augustine grass spreads through above-ground stems called stolons, so it has good self-repair ability if given proper conditions. For small bare spots, improve soil contact by lightly raking the area, apply a thin layer of topsoil or compost, & keep the area consistently moist. The surrounding stolons will gradually fill in the gap. For larger damaged areas, plant St. Augustine grass plugs spaced 6 to 12 inches apart in late spring or early summer when the grass is actively growing. Water the plugs daily for the first two weeks, then gradually reduce to a normal schedule. You can also lay fresh sod for an instant repair. Learn more in our bare spot repair guide.

Can St. Augustine grass grow in shade?

Yes, St. Augustine grass is one of the most shade-tolerant warm-season grasses available. It can thrive with as little as 4 to 5 hours of direct or filtered sunlight per day, making it an excellent choice for lawns with mature trees or partial shade from structures. However, in heavily shaded areas, the grass may thin out over time. To help shaded St. Augustine grass, raise the mowing height to 4 inches to maximize leaf surface area for photosynthesis, reduce nitrogen fertilizer in shaded zones, & prune lower tree branches to allow more light penetration. Varieties like Palmetto & Seville are specifically bred for improved shade tolerance. Explore our shade-tolerant grass guide for additional options.

Final Thoughts on Maintaining a Healthy St. Augustine Lawn

A successful St. Augustine lawn care schedule is built on consistency & timing. By aligning your mowing, fertilizing, watering, & pest management practices with the natural growth cycle of the grass, you create the conditions for a thick, green, weed-resistant lawn that enhances your home's curb appeal year after year.

Remember that every lawn is unique. Soil type, local climate, sunlight exposure, & foot traffic all influence how your St. Augustine grass responds to care. Use this schedule as a foundation, observe how your lawn reacts, & adjust your approach as needed. A soil test every 2 to 3 years provides the data you need to fine-tune your fertilization & pH management strategy.

For more expert lawn care advice, explore our complete library of lawn care guides & learn about other warm-season grass types that may complement your landscaping plans. A beautiful lawn starts with knowledge — & now you have the schedule to make it happen.