St. Augustine grass (Stenotaphrum secundatum) is a popular warm-season turfgrass known for its lush, coarse-bladed, blue-green appearance, making it a favorite for lawns in warm, humid climates, particularly across the southern United States. Its dense growth habit helps suppress weeds, and it tolerates moderate shade better than many other warm-season varieties. However, like all living things, St. Augustine grass can fall victim to stress, disease, or neglect, leading to brown, thinning, or seemingly “dead” patches.

Witnessing your once-thriving St. Augustine lawn turn an unappealing shade of brown can be disheartening. The good news is that often, what appears to be dead is merely dormant or severely stressed grass that can be brought back to life with the right care and intervention. Understanding the specific causes of decline is the first crucial step in developing an effective revival plan. This guide will walk you through how to diagnose, treat, and ultimately revive your struggling St. Augustine lawn, offering insights into common stressors and practical steps for restoration.

Can I Revive Dead St. Augustine Grass?

The short answer is: sometimes, but not always.

The key differentiator is whether the grass is truly “dead” or merely “dormant” or “severely stressed.”

  • Dormant Grass: St. Augustine grass, being a warm-season grass, can enter dormancy during periods of extreme drought, cold temperatures (below 50°F / 10°C), or prolonged heat stress. When dormant, the blades turn brown and crispy, but the crown of the plant and its stolons (above-ground runners) may still be alive. If the stolons are still pliable and green when bent or scraped, there’s a good chance for revival once favorable conditions return and proper care is provided.
  • Severely Stressed Grass: Your St. Augustine might look terrible due to a lack of water, nutrient deficiency, pest infestation, or disease. In these cases, the grass isn’t dead but is struggling. If you catch the problem early enough and address the underlying cause, the grass can often recover.
  • Truly Dead Grass: If the stolons are brittle, dry, and snap easily, or if you can pull up patches of grass with no resistance and no signs of green in the crown, then the grass is likely dead. Once the entire plant, including its root system and stolons, has died, it cannot be revived. In such cases, the only option is to remove the dead patches and replant with new sod, plugs, or seed (though seeding St. Augustine is often less common and slower than using sod or plugs).

How to Check for Life: Gently tug on the brown blades. If they pull up easily, the grass is likely dead. If they resist and you see any hint of green at the base of the blades or in the stolons (the runners across the soil surface), there’s still life. You can also try scraping a small section of a stolon with your thumbnail; if it’s green underneath, it’s alive.

The earlier you identify and address the issue, the higher the likelihood of a successful revival.

Steps for Revival

Reviving St. Augustine grass requires a systematic approach, addressing potential problems one by one until the lawn begins to show signs of recovery.

Step 1: Diagnose the Problem

Before you do anything else, try to determine why your grass is struggling. This often involves a bit of detective work.

  • Observe Patterns: Are the brown spots uniform, or are they localized? Are they near a downspout, under a tree, or in a high-traffic area?
  • Check for Pests: Look for insects like chinch bugs (tiny, black-and-white insects found at the base of the grass blades, especially at the edge of brown spots) or grubs (white, C-shaped larvae that feed on roots, causing grass to pull up like carpet).
  • Inspect for Disease: Look for fungal indicators like leaf spots, irregular patch shapes, or mycelium (spider-web-like fungal growth). Common St. Augustine diseases include Brown Patch (large, circular, browning patches) and Take-All Root Rot (irregular yellowing patches that turn brown).
  • Assess Soil Moisture: Stick a screwdriver or probe into the soil. Is it bone dry, or waterlogged? Overwatering and underwatering are both common culprits.
  • Check for Compacted Soil: Try pushing a screwdriver into the soil. If it’s very difficult to push in, your soil is likely compacted.
  • Consider Nutrient Deficiencies: Prolonged yellowing, despite adequate water, might indicate a lack of nutrients. A soil test can confirm this.

Step 2: Adjust Watering Practices

Proper watering is the single most important factor for St. Augustine’s health.

  • Underwatering/Drought Stress: If the soil is dry, begin deep and infrequent watering. Apply 1 inch of water (from rain or irrigation) once or twice a week, allowing the topsoil to dry slightly between waterings. This encourages deep root growth. Water early in the morning to reduce evaporation and disease risk.
  • Overwatering/Poor Drainage: If the soil is soggy, stop watering immediately. Check for drainage issues (see previous articles on muddy yards and standing water). Reduce watering frequency, ensuring the soil has a chance to dry out between sessions. Overwatering can lead to root rot and fungal diseases.

Step 3: Address Pests and Diseases

If your diagnosis points to pests or diseases, immediate action is needed.

  • Pest Control:
    • Chinch Bugs: Apply an insecticide specifically labeled for chinch bugs on St. Augustine grass. Follow label directions carefully.
    • Grubs: Apply a grub control product. Timing is crucial for effectiveness (often late spring/early summer for preventative, or late summer/early fall for curative).
  • Disease Management:
    • Fungicides: For fungal diseases like Brown Patch or Take-All Root Rot, apply a fungicide labeled for your specific disease and grass type. Multiple applications may be necessary.
    • Cultural Practices: Improve air circulation (e.g., prune surrounding shrubs), reduce thatch, and adjust watering practices (avoiding evening watering) to create less favorable conditions for fungal growth.

Step 4: Improve Soil Conditions

Healthy soil is the foundation of a healthy lawn.

  • Aeration: If soil is compacted, core aeration can significantly help. It creates channels for water, air, and nutrients to penetrate, promoting deeper root growth. Do this during St. Augustine’s active growing season (late spring/early summer).
  • Dethatching: If you have a thick layer of thatch (dead organic matter between the soil surface and grass blades), it can impede water and nutrient absorption and harbor pests/diseases. Dethatch St. Augustine when it’s actively growing.
  • Soil Amendments: Based on a soil test, apply necessary amendments.
    • pH Correction: St. Augustine prefers a slightly acidic to neutral pH (6.0-7.0). Apply lime to raise pH or sulfur to lower it, if needed.
    • Nutrient Deficiencies: Apply appropriate fertilizers to address nutrient shortfalls.

Step 5: Proper Fertilization

  • Purpose: To provide essential nutrients for recovery and vigorous growth.
  • How: Once you’ve addressed underlying issues and the grass shows signs of life, apply a balanced fertilizer or one tailored for St. Augustine grass. Look for formulations with potassium, which helps with stress tolerance. Avoid excessive nitrogen, especially if disease is present, as it can promote fungal growth.
  • Timing: Fertilize during St. Augustine’s active growing season (late spring through early fall), typically every 6-8 weeks. Follow product instructions.

Step 6: Fill in Bare Spots (If Necessary)

  • For truly dead patches: If sections of your St. Augustine lawn are beyond revival, you’ll need to replant.
    • Sodding: Laying new sod is the fastest way to repair large dead areas. Ensure good soil contact and water diligently.
    • Plugging: St. Augustine spreads by stolons, so planting plugs (small squares of sod) can fill in bare areas over time. Space them 1-2 feet apart.
    • Sprigging: Spreading stolons and rhizomes over the surface.
    • Seeding: While St. Augustine seed is available, it’s generally slow to establish and less reliable than sod or plugs.

Step 7: Ongoing Maintenance

Once your St. Augustine is on the road to recovery, consistent, proper maintenance is crucial to prevent future issues.

  • Mow Correctly: Mow at the recommended height (2.5-4 inches, depending on variety and shade) with a sharp blade. Never remove more than one-third of the blade height at a time.
  • Regular Inspections: Periodically check your lawn for early signs of pests, diseases, or water stress.
  • Weed Control: Manage weeds, as they compete with St. Augustine for resources. Use pre-emergent herbicides in spring and fall (but be careful if you plan to plant new sod/plugs).

What Kills St. Augustine Grass?

Understanding the primary threats to St. Augustine grass can help you prevent future decline.

  1. Drought/Underwatering: St. Augustine needs consistent moisture. Prolonged dry spells without irrigation will cause it to go dormant and eventually die.
  2. Overwatering/Poor Drainage: Too much water can suffocate roots, lead to root rot, and encourage fungal diseases. Compacted soil exacerbates this problem.
  3. Chinch Bugs: These tiny insects suck the sap from St. Augustine blades, causing irregular brown patches that quickly spread. They are a notorious killer of this grass type, especially in hot, dry conditions.
  4. Fungal Diseases:
    • Brown Patch: Causes circular browning patches, often with a yellow halo. Thrives in warm, humid, and overly wet conditions with high nitrogen.
    • Take-All Root Rot (TARR): A severe root and stolon rot that causes irregular patches of yellowing, thinning, and eventual death. It’s often worse in alkaline, wet soils.
  5. Freezing Temperatures: As a warm-season grass, St. Augustine is not cold-hardy. Prolonged freezing temperatures can kill it, especially without adequate winter preparation.
  6. Incorrect Herbicide Application: St. Augustine is sensitive to certain herbicides (e.g., those containing 2,4-D or MCPP in higher concentrations). Always read herbicide labels carefully to ensure they are safe for St. Augustine grass.
  7. Nutrient Deficiencies/Imbalances: Lack of essential nutrients, particularly iron (leading to chlorosis or yellowing), or an imbalance in pH, can weaken the grass and make it susceptible to other issues.
  8. Excessive Thatch: A thick layer of thatch (over 1 inch) can prevent water and nutrients from reaching the soil, harbor pests, and make the lawn more susceptible to disease.
  9. Soil Compaction: Prevents water and air from reaching roots, leading to weak, struggling grass that is prone to death.

Best Professional Lawn Care: TruGreen

When your St. Augustine grass is severely struggling, or if you simply prefer to leave lawn care to the experts, professional lawn care services can be a valuable investment. Companies like TruGreen offer comprehensive programs designed to address common lawn issues, including those specific to warm-season grasses like St. Augustine.

TruGreen typically provides a range of services that can directly benefit a struggling St. Augustine lawn:

  • Soil Analysis: They often start with a professional soil analysis to identify nutrient deficiencies or pH imbalances, which are critical for customized fertilization plans.
  • Customized Fertilization: Based on soil tests and the specific needs of St. Augustine grass, they apply targeted fertilizers throughout the year to promote healthy growth and recovery.
  • Weed Control: TruGreen offers pre-emergent and post-emergent weed control programs to minimize weed competition, which is vital for new or recovering St. Augustine.
  • Insect Control: They provide solutions for common St. Augustine pests like chinch bugs and grubs, applying insecticides at the appropriate times.
  • Disease Management: Some programs include fungicide applications to manage common St. Augustine diseases like Brown Patch or Take-All Root Rot.
  • Aeration: Depending on the program, they may offer core aeration services to alleviate soil compaction and improve drainage.

Benefits of Professional Care:

  • Expertise: Professionals have in-depth knowledge of grass types, local pests, diseases, and soil conditions.
  • Convenience: They handle the complex timing and application of products.
  • Specialized Products: They often have access to professional-grade products not available to homeowners.
  • Ongoing Monitoring: Regular visits allow them to monitor your lawn’s health and address issues proactively.

While professional services come at a cost, they can save homeowners significant time, effort, and frustration, especially when dealing with complex or widespread lawn problems. When considering a professional service, inquire about their specific programs for warm-season grasses, their approach to integrated pest management, and read customer reviews to ensure they are a good fit for your needs.

Final thoughts

A brown or thinning St. Augustine lawn is a distress signal that shouldn’t be ignored. While it can be alarming, many instances of decline are reversible if caught early and addressed correctly. The fundamental approach involves a bit of detective work to identify the underlying cause, followed by targeted interventions that restore the grass’s essential needs.

From correcting watering habits and amending compacted soil to battling stubborn pests or diseases, each step contributes to creating an environment where St. Augustine grass can thrive. Remember that consistency is key; a single application or action might not be enough. Regular monitoring, proper mowing, and a tailored fertilization program are crucial for long-term health. If the task feels overwhelming, or if your lawn’s problems are particularly severe, don’t hesitate to consult with a local lawn care professional or extension service for expert guidance. With patience and the right strategy, you can often bring your St. Augustine grass back to its vibrant, lush glory, ensuring your yard remains a beautiful and inviting space.