St. Augustine grass establishes best when planted in late spring or early summer, allowing full root development before winter. Knowing when to plant st augustine is the single most important factor for a thick, green lawn that chokes out weeds and handles foot traffic well. Get the timing wrong, and you risk frost damage, poor rooting, or a patchy yard that needs constant reseeding.
This guide covers everything you need: the ideal planting window for your region, step-by-step preparation, and how to care for new sod or plugs. You will learn exactly when to put St. Augustine in the ground so it thrives.
When To Plant St Augustine: The Ideal Window
The best time to plant St. Augustine grass is when soil temperatures are consistently between 70°F and 90°F. Air temperature should be warm, but not scorching hot. For most of the southern United States, this means planting from late April through early July.
Planting too early in spring risks a late frost that kills tender new growth. Planting too late in summer or early fall means the grass won’t have enough time to establish deep roots before winter dormancy sets in. A weak root system leads to winter kill and bare spots come spring.
Why Late Spring And Early Summer Work Best
St. Augustine is a warm-season grass. It grows actively when temperatures are high and days are long. Here is why this window is critical:
- Soil warmth encourages rapid root growth from sod or plugs.
- Long daylight hours maximize photosynthesis for energy storage.
- Warm nights prevent stress that slows establishment.
- Rainfall is often more reliable in late spring, reducing the need for constant watering.
If you plant in this window, your St. Augustine will have 60 to 90 days of active growth before the first fall frost. That is enough time for roots to reach 6 to 8 inches deep, which is the minimum for winter survival.
Regional Timing Differences
Your exact planting date depends on where you live. Here is a breakdown by region:
- Gulf Coast (Texas, Louisiana, Mississippi, Alabama, Florida): Plant from mid-April to mid-June. Soil warms early here. Avoid planting during the peak heat of July and August unless you can water heavily.
- Southeast (Georgia, South Carolina, North Carolina): Plant from late April to early July. Coastal areas can plant a bit earlier than inland regions.
- California (Central Valley and coastal areas): Plant from May to June. Inland valleys with hot summers can plant as early as April.
- Transition zone (Tennessee, Arkansas, Oklahoma, Virginia): Plant from late May to mid-June. This zone has colder winters, so earlier planting is risky. Stick to the later end of the window.
If you are unsure, check your local extension office’s soil temperature map. Wait until soil at 4 inches deep is consistently above 65°F before planting.
How To Prepare Your Soil For St. Augustine
Good soil preparation makes a huge difference in how fast your grass establishes. St. Augustine prefers slightly acidic soil with a pH between 6.0 and 6.5. It also needs good drainage and organic matter.
Step 1: Test Your Soil
Buy a simple soil test kit from a garden center or send a sample to your local extension office. You need to know the pH and nutrient levels. If pH is below 6.0, add lime. If above 7.0, add sulfur. Do this at least two weeks before planting.
Step 2: Clear The Area
Remove all existing grass, weeds, rocks, and debris. Use a sod cutter or a non-selective herbicide like glyphosate. Wait 7 to 10 days after spraying to ensure weeds are dead. Then rake the area smooth.
Step 3: Amend The Soil
Spread 1 to 2 inches of compost or well-rotted manure over the soil. Till it in to a depth of 4 to 6 inches. This improves drainage and adds nutrients. If your soil is heavy clay, add sand or gypsum to break it up.
Step 4: Level And Firm The Soil
Rake the soil so it is smooth and slightly sloped away from buildings. Use a lawn roller filled with water to firm the surface. This prevents air pockets that dry out roots. Water the area lightly to settle the soil.
Planting Methods: Sod, Plugs, Or Seed
St. Augustine is almost always planted as sod or plugs. Seed is rarely used because it is expensive, slow to germinate, and less reliable. Here is how to handle each method.
Planting St. Augustine Sod
Sod gives you an instant lawn. It is the most common method for St. Augustine. Follow these steps:
- Order fresh sod from a local farm. It should be cut within 24 hours of delivery.
- Lay the sod within 24 hours of delivery. Do not let it sit rolled up in the sun.
- Start along a straight edge like a driveway or sidewalk. Butt the pieces tightly together without overlapping.
- Stagger the seams like brickwork. This prevents visible lines.
- Use a sharp knife to cut pieces around curves and obstacles.
- Roll the entire area with a half-filled roller to press roots into the soil.
- Water deeply immediately after laying. Keep the sod moist for the first two weeks.
Planting St. Augustine Plugs
Plugs are small sections of grass planted in holes. They are cheaper than sod but take longer to fill in. Here is the process:
- Space plugs 12 to 18 inches apart in a grid pattern. Closer spacing fills in faster.
- Dig holes slightly larger than the plug root ball.
- Place each plug so the top of the root ball is level with the soil surface.
- Firm the soil around each plug with your hands.
- Water thoroughly after planting. Keep the area moist for the first three weeks.
Plugs take 6 to 12 months to fully cover the ground, depending on spacing and growing conditions. Be patient and keep weeds out during establishment.
Watering Schedule For New St. Augustine
Water is the most critical factor after planting. New St. Augustine has a shallow root system and dries out fast. Here is a simple watering schedule:
- First 2 weeks: Water daily, sometimes twice a day if it is hot. Apply about 1/4 to 1/2 inch of water each time. The soil should stay moist but not soggy.
- Weeks 3 to 6: Water every other day. Apply 1/2 to 3/4 inch per session. Let the soil dry slightly between waterings to encourage deeper root growth.
- Weeks 7 to 12: Water twice a week. Apply 1 inch per session. By now, roots should be 4 to 6 inches deep.
- After 12 weeks: Water once a week with 1 to 1.5 inches if there is no rain. Your grass is established.
Use a rain gauge or a tuna can to measure water output. Early morning watering is best to reduce evaporation and disease risk.
Fertilizing New St. Augustine
Do not fertilize immediately after planting. Wait until the grass shows new growth, usually 2 to 4 weeks after sod or plugs are laid. Then apply a starter fertilizer high in phosphorus.
Use a balanced fertilizer like 15-15-15 or a lawn starter formula. Apply at half the recommended rate to avoid burning tender roots. Water it in well after application.
After the first month, switch to a nitrogen-rich fertilizer. Apply every 6 to 8 weeks during the growing season. Stop fertilizing 6 weeks before the first expected frost to prevent tender growth that winter kills.
Common Mistakes When Planting St. Augustine
Avoid these errors to save time and money:
- Planting too early: Cold soil and frost kill new grass. Wait until soil is warm.
- Planting too late: Grass needs 60 days of growth before frost. Late planting leads to winter kill.
- Overwatering: Soggy soil causes root rot and fungus. Water deeply but infrequently after the first two weeks.
- Underwatering: New grass dries out fast. Check soil moisture daily during the first month.
- Mowing too soon: Wait until the grass is at least 3 inches tall. Mow at the highest setting to avoid scalping.
- Ignoring weeds: Weeds compete for water and nutrients. Hand pull or spot treat with a St. Augustine-safe herbicide.
Mowing New St. Augustine
Do not mow until the grass is firmly rooted. For sod, this takes about 2 to 3 weeks. For plugs, wait until they have spread and are at least 3 inches tall.
Set your mower blade to the highest setting, around 3 to 4 inches. St. Augustine should never be cut shorter than 2.5 inches. Scalping stresses the grass and invites weeds and disease.
Only remove one-third of the leaf blade per mowing. If the grass gets too tall, mow twice over a few days to gradually reduce height. Keep mower blades sharp to avoid tearing the leaves.
Winter Care For New St. Augustine
If you planted in late spring, your grass should be well-established by winter. But if you planted later than recommended, you need extra care:
- Apply a winterizer fertilizer in early fall to boost root reserves.
- Keep leaves raked off the lawn to prevent smothering.
- Avoid walking on frozen grass. It damages the crowns.
- If you live in a cold zone, consider covering new grass with straw or a frost blanket during hard freezes.
Come spring, check for winter kill. Bare spots can be filled with plugs or sod in late spring.
Frequently Asked Questions
Can I Plant St. Augustine In The Fall?
It is risky. Fall planting gives the grass little time to root before winter. Only do it in warm climates like southern Florida or Texas coastal areas. Even then, plant by early September.
What Is The Best Month To Plant St. Augustine In Texas?
May is ideal for most of Texas. Soil is warm, and summer rains help establishment. In far south Texas, April works. In the Panhandle, wait until June.
How Long Does It Take For St. Augustine Plugs To Fill In?
Plugs spaced 12 inches apart fill in about 3 to 4 months under ideal conditions. Wider spacing takes 6 to 12 months. Keep weeds out and water consistently.
Should I Plant St. Augustine From Seed?
Seed is not recommended for home lawns. It is expensive, slow to germinate, and the resulting grass is less vigorous. Sod or plugs are far more reliable.
Can I Plant St. Augustine Over Existing Grass?
No. You must remove all existing grass and weeds first. St. Augustine does not compete well with other grasses. Kill the old lawn completely before planting.
Final Tips For Success
Planting St. Augustine at the right time is half the battle. The other half is consistent care during the first few months. Water deeply, mow high, and keep weeds out. Your lawn will reward you with a dense, green carpet that lasts for years.
If you are unsure about your local conditions, ask a neighbor with a good St. Augustine lawn when they planted. Or call your county extension office. They know the exact timing for your area.
Remember: patience pays off. Do not rush the process. Wait for warm soil, prepare the ground well, and give your new grass the care it needs. You will have a lawn you can be proud of.