St. Augustine grass (Stenotaphrum secundatum) is a popular warm-season turfgrass known for its lush, blue-green color and thick, coarse blades. It’s a favorite in warm, humid climates, particularly across the Southern United States, because of its excellent heat and salt tolerance, and its ability to grow well in partial shade where other warm-season grasses might struggle. Unlike many other lawn grasses, St. Augustine is typically not grown from seed due to its low germination rates and slow establishment. Instead, it is most commonly “spread” or propagated vegetatively using sod, plugs, or sprigs.

Establishing a St. Augustine lawn, or repairing bare spots, can create a dense, beautiful turf that effectively chokes out many weeds. This guide will walk you through the various methods of spreading St. Augustine grass, from preparing your site to ongoing maintenance, ensuring a successful and vibrant lawn.

When To Plant St. Augustine Grass

Timing is a critical factor for successful St. Augustine grass establishment. As a warm-season grass, it thrives in heat and requires specific temperature conditions for optimal growth and rooting.

The best time to plant St. Augustine grass, whether using sod, plugs, or sprigs, is during its active growing season, which is typically late spring through early summer.

  • Ideal Temperature Range: Soil temperatures should consistently be above 65°F (18°C), and ideally between 70-90°F (21-32°C). This usually corresponds to air temperatures reliably above 80°F (27°C).

  • Why this timing?

    • Rapid Rooting and Spreading: Warm soil temperatures promote quick root development, allowing the grass to establish itself efficiently and begin spreading via its stolons (above-ground runners).
    • Reduced Stress: Planting during its peak growth period minimizes transplant shock and allows the grass to quickly overcome any initial stress.
    • Avoids Cold Damage: Planting too late in the fall can lead to poor establishment before cooler temperatures arrive, making the young grass vulnerable to winter stress or freeze damage.
    • Avoids Extreme Heat (initial phase): While St. Augustine loves heat, establishing new sod or plugs during the absolute peak of summer (e.g., July-August in extremely hot climates) can be challenging due to intense sun and high water demand. If planting in peak summer, be prepared for extremely diligent watering.

  • Regional Considerations:

    • Southern U.S. (Florida, Gulf Coast, etc.): Planting can often begin in April and extend through September.
    • Transition Zones (e.g., northern parts of its range): May is often the earliest safe time, and it’s best to complete planting by July to allow sufficient time for establishment before fall.

In summary, aim for a period when consistent warm weather is expected, ensuring at least 6-8 weeks of ideal growing conditions for the grass to root deeply before any significant temperature drops.

How To Prepare the Planting Area

Proper site preparation is paramount to the long-term success of your St. Augustine lawn. Neglecting this step can lead to poor establishment, weed problems, and a less-than-ideal turf.

  1. Clear the Area:

    • Remove Existing Vegetation: This is the most crucial step. Thoroughly remove all existing weeds, grass, and debris (rocks, roots, trash).
      • Manual Removal: For small areas, hand-digging or raking can suffice. Ensure all roots and rhizomes of perennial weeds are removed.
      • Chemical Application: For larger areas or stubborn weeds, consider using a non-selective herbicide like glyphosate. Apply according to label directions and allow sufficient time (usually 7-14 days) for the vegetation to die completely before proceeding. Multiple applications may be needed for very persistent weeds.
      • Solarization: In hot, sunny climates, solarization (covering the area with clear plastic for 6-8 weeks during summer) can kill existing vegetation and weed seeds.

  2. Rough Grade for Drainage:

    • Ensure Proper Slope: Grade the area away from foundations, driveways, and sidewalks to ensure proper water drainage. A slight slope of 1-2% (1-2 feet drop per 100 feet) is generally adequate.
    • Fill Low Spots: Fill any low spots or depressions where water might collect, as St. Augustine, while loving humidity, does not thrive in consistently waterlogged conditions.

  3. Test the Soil:

    • Importance: A soil test is highly recommended. It will tell you your soil’s pH and nutrient levels, guiding necessary amendments. Contact your local extension office for testing kits and instructions.
    • St. Augustine’s Preference: St. Augustine grass generally prefers a slightly acidic to neutral pH, ranging from 6.0 to 7.5.
    • Amendments:
      • If pH is too low (acidic), add lime as recommended by the soil test.
      • If pH is too high (alkaline), add sulfur.
      • Add any recommended nutrients (phosphorus, potassium) if deficient.

  4. Amend the Soil (if necessary):

    • Improve Soil Structure: While St. Augustine tolerates various soil types, amending heavy clay soils with organic matter (e.g., compost, well-rotted manure, peat moss) will improve drainage and aeration. For sandy soils, organic matter will improve water and nutrient retention.
    • Depth: Incorporate organic matter to a depth of 4-6 inches using a rototiller or garden fork.
    • Final Rake: Rake the entire area smooth and level, removing any remaining debris or large clods. The surface should be firm enough that you don’t sink deeply when walking on it, but not compacted.

Planting Methods for St. Augustine Grass

St. Augustine grass is primarily propagated vegetatively, meaning from parts of the plant rather than seeds. The most common methods are sod, plugs, and sprigs, each with its own advantages, costs, and establishment times.

1. Sodding (Instant Lawn)

  • Description: Sod consists of mature St. Augustine grass grown on a thin layer of soil, harvested in rolls or squares.
  • Pros:
    • Instant Lawn: Provides an immediate green lawn.
    • Fast Establishment: Roots quickly into the prepared soil, typically within 2-4 weeks.
    • Weed Suppression: Its density immediately smothers most weeds.
  • Cons:
    • Highest Cost: Most expensive method.
    • Labor Intensive: Can be heavy to transport and lay.
    • Time Sensitive: Sod needs to be laid immediately upon delivery, ideally within 12-24 hours, to prevent drying out.
  • Installation:
    1. Moisten Soil: Lightly moisten the prepared soil before laying sod.
    2. Lay Sod: Start along a straight edge (like a driveway or patio). Lay sod pieces tightly together in a staggered, brick-like pattern, ensuring no gaps. Avoid stretching or overlapping.
    3. Trim: Use a sharp utility knife or shovel to cut sod pieces to fit curves or edges.
    4. Roll/Tamp: After laying, roll the entire area with a lawn roller (or tamp lightly by walking on it) to ensure good sod-to-soil contact and remove air pockets.
    5. Water Immediately: Water the newly laid sod thoroughly, aiming for the top 4-6 inches of soil to be wet. Keep it consistently moist (multiple light waterings per day) for the first 2-3 weeks.

2. Plugging (Economical for Smaller Areas)

  • Description: Plugs are small squares or circles of established St. Augustine grass.
  • Pros:
    • More Economical: Cheaper than sod.
    • Less Labor Intensive (initial): Easier to transport and plant than sod.
    • Good for Repair: Ideal for filling in bare spots or establishing a smaller lawn.
  • Cons:
    • Slower Establishment: Takes longer to fill in (6-12 months, sometimes longer) compared to sod.
    • Weed Competition: More vulnerable to weeds until the plugs spread and coalesce.
  • Installation:
    1. Prepare Holes: Use a specialized plugger tool or a trowel to dig holes in your prepared soil, typically 6-12 inches apart in a checkerboard pattern. Holes should be slightly larger than the plugs.
    2. Plant Plugs: Place one plug in each hole, ensuring the top of the plug is level with the surrounding soil. Gently firm the soil around each plug.
    3. Water Immediately: Water the entire area thoroughly after planting.
    4. Post-Planting: Keep the plugs and surrounding soil consistently moist until they start to spread.

3. Sprigging (Most Economical, Slowest Establishment)

  • Description: Sprigs are individual stolons (runners) or small pieces of stolons with at least one node (a growing point). They usually come without soil attached.
  • Pros:
    • Most Economical: Cheapest method for large areas.
  • Cons:
    • Slowest Establishment: Can take 12-18 months or more to fully establish a dense lawn.
    • Highest Weed Competition: Extremely vulnerable to weeds due to large amounts of exposed soil.
    • Labor Intensive: Can be tedious to spread and plant.
  • Installation:
    1. Prepare Sprigs: Purchase sprigs or harvest them from an existing St. Augustine lawn.
    2. Spread: Broadcast the sprigs evenly over the prepared soil, ensuring good contact with the ground. A general guideline is 5-10 bushels of sprigs per 1,000 sq ft.
    3. Press In: Lightly roll the area or use a rake to ensure the sprigs are pressed into the soil. Some prefer to lightly cover sprigs with a thin layer of topsoil (no more than 1/4 inch) but ensure the nodes are not buried too deeply.
    4. Water Immediately: Water the entire area thoroughly.
    5. Post-Planting: Keep the area consistently moist for several weeks, similar to plug installation.

Fertilizing Newly Planted St. Augustine Grass

Fertilizing newly planted St. Augustine grass is crucial for promoting strong root development and rapid establishment. However, the type and timing of fertilizer application are critical to avoid damaging the tender new grass.

  1. Before Planting (Optional but Recommended):

    • If your soil test indicated a deficiency in phosphorus (P) or potassium (K), you can incorporate a starter fertilizer into the soil during the preparation phase (Step 3 in “How To Prepare the Planting Area”).
    • Look for a starter fertilizer with a high middle number (e.g., 5-10-15 or 10-20-10), indicating a higher phosphorus content, which is vital for root growth.
    • Apply as per product instructions and rake it into the top few inches of soil.

  2. After Planting (for Sod, Plugs, and Sprigs):

    • Delay Nitrogen: Avoid applying a high-nitrogen fertilizer (high first number, e.g., 30-0-0) immediately after planting. This can burn new sod, plugs, or sprigs and encourage top growth at the expense of root development.
    • First Fertilization (2-3 weeks after planting):
      • Once the sod has begun to root (you can’t easily lift it) or the plugs/sprigs show signs of new growth (typically 2-3 weeks after planting), you can apply a balanced, slow-release starter fertilizer or a general-purpose lawn fertilizer with a lower nitrogen content.
      • Look for formulations like 15-5-10 or similar. The “slow-release” aspect is important to provide nutrients gradually without overwhelming the young grass.
      • Apply at the rate recommended on the product label.

  3. Subsequent Fertilization (30-45 days after planting):

    • After the initial establishment period (about 1-1.5 months), you can transition to a regular St. Augustine fertilization program.
    • Apply a slow-release nitrogen fertilizer suitable for warm-season grasses. St. Augustine thrives on nitrogen for its green color and dense growth.
    • Follow the recommended application rates and schedule for your specific climate. Typically, St. Augustine benefits from fertilization every 6-8 weeks during its active growing season.

Key Considerations:

  • Soil Test is Best: Always base your fertilization strategy on the results of a soil test.
  • Water In: Always water your lawn immediately after applying granular fertilizer to prevent burn and help the nutrients reach the soil.
  • Don’t Over-fertilize: Too much fertilizer can stress or burn new grass. More is not better.
  • Granular vs. Liquid: Slow-release granular fertilizers are generally preferred for new establishments as they provide a consistent supply of nutrients.

Maintenance Tips for St. Augustine Grass

Once your St. Augustine grass is planted, ongoing maintenance is crucial for successful establishment and a healthy, thriving lawn.

  1. Watering (Most Important):

    • Initial Phase (First 2-3 weeks for sod; 4-6 weeks for plugs/sprigs): Keep the top 1-2 inches of soil consistently moist. This means frequent, light waterings throughout the day (e.g., 2-3 times a day for 10-15 minutes, depending on heat and soil type). The goal is to prevent the sod or plugs from drying out.
    • Transition Phase: Once the grass starts rooting well, gradually decrease the frequency of watering but increase the duration. This encourages deeper root growth.
    • Established Lawn: Water deeply and infrequently. Aim for 1 inch of water per week (from rain or irrigation), applied in one or two sessions, to encourage deep root systems and drought tolerance. Water early in the morning to reduce disease risk.

  2. Mowing:

    • Delay First Mow: Do not mow newly laid sod until it has firmly rooted (test by gently tugging on a corner – if it resists, it’s ready). For plugs and sprigs, wait until they have significantly spread and grown. This usually takes 2-3 weeks for sod, longer for others.
    • Mow High: St. Augustine grass performs best when mowed at a height of 2.5 to 4 inches. Mowing too short stresses the grass, especially in hot weather, and encourages weed growth.
    • “One-Third Rule”: Never remove more than one-third of the blade height in a single mowing. If the grass is tall, mow more frequently or raise the deck.
    • Sharp Blades: Always use a mower with sharp blades to ensure a clean cut, which promotes healthier growth and reduces disease susceptibility.

  3. Weed Control:

    • Manual Removal: Hand-pulling weeds is the safest method for newly planted St. Augustine, especially for plugs and sprigs, as herbicides can damage young grass.
    • Delay Herbicides: Avoid applying pre-emergent herbicides for at least 60-90 days after planting, as they can inhibit rooting and growth. Post-emergent herbicides should only be used once the grass is fully established (after 2-3 months or several mowings) and specifically labeled as safe for St. Augustine grass.
    • Dense Turf: A healthy, dense St. Augustine lawn will naturally outcompete many weeds.

  4. Pest and Disease Monitoring:

    • Regularly inspect your lawn for signs of common St. Augustine pests (e.g., chinch bugs, grubs) or diseases (e.g., brown patch, gray leaf spot). Address any issues promptly.

  5. Thatch Management:

    • St. Augustine grass is prone to thatch buildup (a layer of dead and living organic matter between the soil surface and green blades). Excessive thatch can hinder water penetration and harbor pests/diseases.
    • Light dethatching or verticutting may be needed every few years once the lawn is mature.

So, Is Spreading St. Augustine Grass Worth the Effort?

Despite the initial effort involved in site preparation and planting, establishing a St. Augustine lawn is often well worth it for homeowners in suitable climates.

Pros of St. Augustine Grass:

  • Exceptional Heat Tolerance: Thrives in hot, humid summers where many other grasses struggle.
  • Moderate Shade Tolerance: Performs better than Bermudagrass in partially shaded areas (though it still prefers at least 4-6 hours of direct sun).
  • Salt Tolerance: Good choice for coastal regions or areas where irrigation water may have higher salt content.
  • Dense Growth: Its thick, horizontal stolons create a very dense turf that naturally chokes out many weeds, reducing the need for herbicides over time.
  • Attractive Appearance: Features a lush, blue-green color and coarse texture that many find appealing.
  • Low Maintenance (Once Established): Once established, it generally requires less frequent mowing than some other warm-season grasses and is relatively drought-tolerant.

Cons of St. Augustine Grass:

  • Poor Cold Tolerance: Goes dormant and turns brown in cooler temperatures and is not suitable for areas with prolonged freezing conditions.
  • Susceptible to Chinch Bugs: Particularly susceptible to chinch bug infestations, especially in hot, dry conditions.
  • Prone to Thatch: Its vigorous growth often leads to thatch buildup, which may require periodic dethatching.
  • Not Wear Tolerant (relative): While dense, it’s not as tolerant of heavy foot traffic as Bermudagrass.
  • Limited Seed Availability: Must be established from sod, plugs, or sprigs, which can be more costly and labor-intensive initially than seeding.
  • Iron Deficiency: Can be prone to iron chlorosis (yellowing) in alkaline soils, requiring iron supplements.

For those in the right climate, the benefits of a beautiful, resilient St. Augustine lawn typically outweigh the initial efforts. Its low maintenance once established and ability to thrive in challenging conditions make it a rewarding choice for many homeowners.

FAQs About St. Augustine Grass

Q: Can I grow St. Augustine grass from seed? A: While St. Augustine grass does produce seeds, they have very poor germination rates and are notoriously difficult to establish. For this reason, it is almost exclusively propagated vegetatively using sod, plugs, or sprigs for reliable results.

Q: How long does it take for St. Augustine plugs or sprigs to fill in? A: It depends on the spacing, growing conditions, and time of year. Plugs typically take 6-12 months to completely fill in, while sprigs can take 12-18 months or even longer for a full, dense lawn. Optimal warm temperatures and consistent watering will accelerate the process.

Q: Why is my new St. Augustine sod turning brown? A: The most common reason is insufficient watering. Newly laid sod needs consistent moisture (top 4-6 inches of soil) for the first few weeks to root properly. Other causes could include disease, insect activity (like chinch bugs), or soil issues.

Q: How often should I water new St. Augustine sod/plugs? A: For the first 2-3 weeks, water newly laid sod lightly 2-3 times a day to keep the top 1-2 inches of soil consistently moist. For plugs and sprigs, the frequency might be similar but for a longer duration (4-6 weeks) until new growth is evident and spreading. Always adjust based on weather conditions and soil type.

Q: When can I fertilize my new St. Augustine lawn? A: If you incorporated a starter fertilizer into the soil before planting, you might not need to fertilize immediately after. Otherwise, wait about 2-3 weeks after planting sod, or when plugs/sprigs show active new growth, then apply a balanced, slow-release starter fertilizer. Follow with a standard St. Augustine fertilizer program about 30-45 days after planting.

Q: Can St. Augustine grass grow in full shade? A: No. While St. Augustine is more shade tolerant than Bermudagrass, it still requires at least 4-6 hours of direct sunlight per day to thrive and maintain its density. In deep shade, it will thin out, become leggy, and be more susceptible to disease. For full shade, consider shade-loving groundcovers or alternative landscaping.

Q: My St. Augustine lawn is developing a thick thatch layer. What should I do? A: Thatch buildup is common with St. Augustine. For established lawns, periodic dethatching (verticutting) every 1-3 years can help. It’s usually best to do this in late spring/early summer when the grass is actively growing and can quickly recover. Proper mowing height and avoiding excessive nitrogen fertilization can also help manage thatch.