St. Augustine grass is a warm-season grass type known for growing a lush, green, beautiful lawn.
Since St. Augustine grass is not tolerant of freezing temperatures, it is only suited to grow in the warmest regions of the United States.
The most popular warm areas for St. Augustine to grow include parts of Texas, Florida, and even South Carolina.
So when is the best time to plant St. Augustine grass?
The optimal time for planting St. Augustine grass is during hot temperatures, usually between 80-100° degrees Fahrenheit (38° C). In areas where it may get cold in the winter months, it is best to plant St. Augustine in full sunlight at least 90 days before the first frost.
Because of the warm temperatures and sunlight requirements, it is best to plant St. Augustine grass in late spring or early summer.
Once your St. Augustine lawn has been planted and established, it will require routine maintenance to keep the grass thick and healthy.
Read on to learn more about growing and maintaining St. Augustine grass.
Table of Contents
Measure Your Lawn For The Right Amount Of St. Augustine Seed
Before planting St. Augustine grass, the first step is to measure your lawn to ensure you buy enough grass plugs or sod.
Determine the square footage of your lawn by measuring the length and width of your yard in feet and multiplying these two numbers together.
Around 18 plugs will cover roughly 32′ square feet when using grass plugs.
If you install sod, you will need to know how many square yards you have because sod is sold.
To find the square yardage of your lawn, divide your square footage measurement by nine.
Give Your St. Augustine The Best Chance: Prepare the Soil
Once you have determined how much St. Augustine grass you need to purchase for planting, it is important to thoroughly prepare your soil.
St. Augustine grass grows best in well-draining sandy soil type with a pH ranging between 5.0 to 8.5.
If your soil has a high clay content, you will need to make some soil amendments to ensure your grass grows thick and full.
We have a post on growing grass in clay soil that will give you the information you need to do that successfully.
Topdressing your lawn with a sand and loam mixture will help improve your soil’s drainage and encourage rapid growth.
Remove any previous grass and weed growth to ensure your new lawn gets a fresh start.
If weeds are a problem in your area, apply a pre-emergent herbicide at least 2-3 weeks before planting your new lawn or installing sod.
Pre-emergent herbicides prevent weed seeds from germinating and sprouting in the spring.
Well-prepared soil also helps your St. Augustine grass develop a robust root system and allows it to spread faster, usually within 14 days after installation.
Apply a Phosphorus Fertilizer
To encourage your new St. Augustine grass to grow healthy roots, apply a starter fertilizer to the soil before planting.
A starter fertilizer is usually high in phosphorus, and you will continue to use this type of fertilizer for the first two months after planting your grass.
A phosphorus-rich fertilizer encourages faster growth, essential if your lawn is not yet established.
After these two months have passed, switch to a slow-release fertilizer with high nitrogen content.
To maintain the spread and growth of your St. Augustine grass, reapply the high-nitrogen fertilizer once every ten weeks.
Thoroughly Water the Area
Once you have applied the starter fertilizer, you will need to thoroughly water it into the soil.
St. Augustine grass requires plenty of water to keep it from going dormant during dry periods.
Take care not to overwater the soil, as you do not want areas of standing water on your lawn.
The soggy ground is not ideal for St. Augustine plug or sod installation.
If you accidentally overwater the soil, you will need to wait a day or two for some of the water to dissipate.
Plant Your New St. Augustine Grass
Since St. Augustine grass is difficult to grow from seeds, most installation is done through plugging or laying sod.
Plugging is much cheaper than sod installation, and there are three densities to choose from when it comes to planting them.
High-density plug installation only requires 6-11″ inches of space between sprigs, and this method will give you fast results because the grass will fill in quickly.
The St. Augustine grass plugs are spaced between 12-18″ inches apart in a typical density plug installation.
With this density, the grass will spread more slowly, and you may have to deal with bare spots on your lawn until the grass is established.
Low-density plug installation spaces the grass plugs 13-24″ inches apart.
Since it will take more than a year to spread and fill in your lawn, this method is only recommended for yards with low foot traffic.
Laying St. Augustine grass sod is the most expensive method of grass installation, but it is the only one with instant results.
You may choose to lay the sod yourself or have it professionally installed.
Water the Grass Daily
If you have planted St. Augustine grass plugs, you will need to water them daily until the plugs have established roots and start to spread.
It usually takes 7-14 days for the grass to establish a strong root system.
After sod installation, it is crucial to water your new lawn for at least 45 minutes to establish the roots in the soil.
After initial installation, water your new sod for 20 minutes at least twice per day to keep the soil moist and prevent the St. Augustine grass from drying out.
Monitor Your New Lawn for Bugs and Diseases
The roots and turf of newly planted St. Augustine grass are vulnerable to diseases and pests.
Keep an eye on your lawn for any brown spots or mildew formation.
If these issues are not treated quickly, they may cause your lawn to die.
If you are unsure of how to remove diseases or pests, you may wish to consult with a lawn care specialist for proper treatment options.
Maintaining Your St. Augustine Grass
With a regular maintenance schedule, it will be possible to keep your St. Augustine grass lush and green throughout the growing season.
St. Augustine tends to be resilient as long as it is planted in the right climate and optimal soil conditions.
Here are a few things you need to do regularly to maintain your new St. Augustine lawn.
Your St. Augustine grass needs the right combination of nitrogen, phosphorus, and potassium to maintain a green lawn.
These essential nutrients provide your lawn with what it needs to maintain strong, healthy growth.
St. Austine grass needs between 3-6 pounds of nitrogen for every 1,000′ square feet of lawn.
Be sure to educate yourself about local ordinances regarding fertilizers, as some areas have restrictions on how much nitrogen you are allowed to use on your lawn within a year.
If your soil has a high pH, usually above 7.0, your grass may turn yellow.
This yellowing indicates your lawn has an iron or manganese deficiency.
Using soluble or chelated forms of these micronutrients will help your grass return to its green color.
Nitrogen is also important for keeping your St. Augustine grass green and healthy.
Most cultivars of St. Augustine grass have a recommended mowing height between 3.5-4″ inches.
Cutting your grass too short will cause it to become stressed, and your grass may turn brown and die.
Never cut more than 1/3 of the length of the grass blades in one mowing session.
Keep your mower blades sharp, and establish a regular mowing routine to maintain a healthy lawn.
You do not need to mow your grass when it is dormant, as this may cause damage to your lawn.
When your St. Augustine grass blades start to wilt, fold, or turn a blue-gray color, these are signs it is time to water your lawn.
You will apply between 1/2-3/4″ inch of water per watering session to ensure the roots receive enough moisture to maintain the grass.
It is best to wait to water until your entire lawn appears dry to avoid encouraging mold and fungal growth.
Overwatering your lawn will not only cause the ground to become soggy and develop standing water, but it will also encourage fungal growth and certain weeds such as dollarweed and sedges.
If there are too many lawn weeds in your yard, they will crowd out the St. Augustine grass and cause stunted growth.
Apply a pre-emergent herbicide in late winter to prevent weeds from sprouting up in the spring.
Post-emergent herbicides may be used throughout the growing season to control annual and perennial broadleaf or grassy weeds.
Always research the weed control product you intend to use to ensure it is compatible with your St. Augustine grass.
The main pest insect affecting St. Augustine grass is the chinch bug.
The damage from chinch bugs will cause your grass to develop yellow or brown patches, and the appearance is very similar to drought-damaged grass.
The effects of a chinch bug infestation are most commonly seen in the spring as the weather starts to get warmer.
Chinch bug control is usually done with an insecticide, but it may take repeated applications to be effective.
Some chinch bug populations are resistant to synthetic pyrethroid insecticides, so choose your treatment carefully.
Other insects such as armyworms, webworms, grass loopers, and mole crickets will cause also cause damage to St. Augustine grass.
Choose the proper insecticide to eliminate these pests, or call a professional to handle it.
The two most common diseases affecting St. Augustine grass are large patch and gray leaf spot.
Large patch is caused by too much nitrogen in the soil, and it usually occurs during warm, humid weather.
Gray leaf spot primarily affects new grass growth, mainly during the rainy summer months.
It is usually best to hire a lawn care specialist to handle these diseases as they are more experienced in diagnosing and treating them.
Nematodes are another type of pest to watch out for in St. Augustine lawns.
Populations of parasitic nematodes usually spike in the early spring and fall seasons.
Damage from nematodes includes a thinner density, stunted growth, and a weakened root system.
Nematodes are only diagnosable through lab processes, which require you to send a soil sample to your local county extension office.
Nematode control options are very expensive, but there are a few things you are able to do to help control their population.
Raise your mowing height to the maximum recommended level to encourage deeper root growth.
It is also crucial to water your lawn deeply but less often.
Another step in nematode control is to add a generous amount of potassium to your soil.
A thick layer of thatch will prevent your St. Augustine grass from receiving the moisture and nutrients it needs to keep your lawn healthy.
If the thatch is thick enough, your grass roots may start to grow aboveground and root into the thatch layer.
This type of root growth makes your grass vulnerable to stress, and the problem needs to be remedied as soon as possible to prevent permanent damage to your St. Augustine grass.
Thatch removal is made easier with a dethatching machine, and it needs to be done at least once or twice per year, depending on how quickly your lawn develops thatch.
Does St. Augustine Spread?
Compared to other warm-season grasses, St. Augustine grass spreads quickly and has a more dense growth pattern.
Thanks to St. Augustine’s hardiness against lawn traffic, it will continue to spread even while the lawn is regularly being used.
This ability for dense growth creates a more lush and thick lawn, with very few instances of bare spots.
Advantages of St. Augustine Grass
St. Augustine grass is very popular in Florida and other coastal regions due to its tolerance of salty soil.
It also boasts a better shade tolerance than most other warm-season grass species.
If you live in a spot with a lot of shade read our post on St. Augustines ability to grow in the shade to learn more.
St. Augustine grass is known for its gorgeous green to blue-green color.
St. Augustine will create a lush and beautiful warm-season lawn combined with its dense growth.
Disadvantages of St. Augustine Grass
The main disadvantage of St. Augustine is its susceptibility to certain pests.
St. Augustine is also limited to growing in warmer regions because it is not tolerant of winter weather.
St. Augustine grass usually experiences a winter dormancy, followed by a spring green-up when warmer temperatures arrive.
Because of its thick growth, this grass also tends to quickly develop thatch layers.
Weed and pest control is also challenging because St. Augustine grass is sensitive to most common chemical lawn treatments.
It is best to use organic lawn care applications whenever possible.
We have a post on bringing back St. Augustine grass and reviving your lawn if you’re having some struggles.