What Are The Best And Worst Types Of Soil For St Augustine Grass?

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St. Augustine grass (Stenotaphrum secundatum) is a lawn grass that gives off a dark green color with its flat, broad blades. Due to the heat and drought tolerance of this grass, it is common in many states along the Gulf. Are you preparing to add some St. Augustine grass to your landscape? You may be wondering how to care for and prepare for this grass, starting with the soil. Good news for you; we have gathered our research to give you insights on the best and worst soil options for your St. Augustine grass. 

The best type of soil for St. Augustine grass is sandy, well-drained soil with a pH of 5 to 6.5. On the other hand, waterlogged, compacted clay soil is the worst type of soil for this grass. 

You know what type of soil is best for your grass, but what other characteristics should your soil have to promote growth? Continue reading as we break down what nutrients St. Augustine grass needs and the best time to lay your sod. 

Up close photographed of healthy St. Augustine grass, What Are The Best And Worst Types Of Soil For St Augustine Grass?

The Best Soil For Your St. Augustine Grass

Sandy soil with a slightly acidic pH is what makes St. Augustine grass happiest. This grass does not do well in compacted clay soil due to the lack of oxygen flow. This grass needs a sufficient oxygen supply to support its growth. Sandy soil provides a loose texture and well-aerated environment, making it ideal for St. Augustine grass.

Soil and grass detailed photo

There are some characteristics of sandy soil that you may need to accommodate for. The loose nature of this soil allows water and fertilizers to leach out quickly.

Check to see if your grass is getting enough water and nutrients frequently. Sandy soil by itself offers little nutrients for your grass or plants. Another reason to ensure your grass is getting the fuel it needs to keep growing. 

What Nutrients Does St Augustine Grass Need?

Completing a soil test allows you to see exactly the types and how much of a nutrient your soil has or lacks. Not only does this test show you nutrients present, but you get the pH. Your St. Augustine grass requires phosphorus, potassium, and a pH of around 5 to thrive. 

Soil tests are part of the needed maintenance of your grass. Fertilizing should be another part of your St. Augustine grass maintenance plan. Using fertilizers that are 16-4-8 or 12-4-8 are perfect for ensuring your grass is getting all the nutrients it needs. 

You can find a 16-4-8 balanced liquid fertilizer here on Amazon.

How Do You Prepare The Soil For St. Augustine Grass?

Before you lay your St. Augustine sod, you must prepare the ground to promote growth right from the start. You prepare the soil by moving any grass or weeds currently growing where you’d like to lay your sod. 

Top view of St. Augustine grass

After mowing, use a garden tiller to turn the soil about 4 inches (10 cm) deep. Pass through the soil from different directions with your tiller to thoroughly loosen your soil. Remove any weeds or rocks present using a rake. Last, you will go over your soil with a sprinkler or hose, creating damp soil that is ready for sod. 

Amazon offers a cordless electric tiller here that is great for soil cultivation.

Learn more on our blog post: For How Long Should You Water A Lawn?

Can You Put Topsoil Over St. Augustine Grass?

You can add topsoil over St. Augustine grass, and you should, in some cases. Topsoil can be added to your grass to level an uneven grass lawn or to add organic nutrients to your grass. 

Healthy St. Augustine grass on a white background

Do you want to take advantage of these organic nutrients? Lay a thin layer of organic soil mixture over the top of your sod. After this layer has been applied, thoroughly water your lawn, allowing the nutrients and soil to seep into the grass. This process can be done twice a year to promote growth and improve the soil for your grass. 

View premium, organic topsoil here on Amazon. 

There are many topsoils to choose from. There are commercial brands made for all lawns and gardens that work great. If you are looking for topsoil that is more St. Augustine specific, try using free-flowing sand or sandy loam soil. Using sand-based soil will further improve water drainage and decrease the chance of your grass getting waterlogged. 

Read more on our blog post: Is Wood Ash Good For Lawn Grass?

When Is The Best Time To Lay St. Augustine Sod?

St. Augustine grass loves the heat. To support growth and quickly spread grass, the best time to lay this grass sod is in the spring and summer months.

Lay your sod in full sun for best results.  If you live in an area that frosts every year, ensure you plant your grass at least 90 days before the first frost. 

You’ll be laying this sod during hot temperatures and full-on sun. With these conditions, it is crucial that water requirements are met.

Newly laid sod may require watering multiple times a day until your grass becomes established. Once established, you can water your grass as needed. The growth period of St. Augustine sod varies depending on aspects of the environment such as temperature, nutrients, and sun exposure. 

Have a look at these disease-resistant St. Augustine Grass sods here on Amazon. 

Can I Lay St. Augustine Sod Over Existing Grass?

If you replace your current grass with St. Augustine sod, it may be tempting to just lay your sod over your existing grass. Will this work? In some instances, this will work, but the chances of good results are low. 

Pallets of St. Augustine grass ready for resale

It is recommended to properly prep your soil before laying down your new sod. This gives your grass the best chance to take off and be healthy. For your sod to grow, it needs to sustain roots in the soil. This process can be delayed or obstructed if you leave your existing grass as a layer between your sod and the ground. 

Up close photo of healthy St. Augustine grass

Leaving your existing grass also creates a competitor for your sod when it comes to nutrients and other resources. Pulling up existing grass sounds like a lot of work, but it will be worth the result of your thriving St. Augustine grass. 

Read more on our blog post: 9 Types Of Sod Grass That May Be A Good Fit For Your Lawn

Can You Mix Bermuda Grass With St Augustine Grass?

You can mix Bermuda grass with St. Augustine grass. This pair actually works well together when maintained and cared for appropriately. Mixing these grasses allows for quicker coverage of your lawn. Having a mix can save you money as well, as Bermuda grass seeds are on the cheaper side. 

Up close photo of St. Augustine grass

With mixed grass or a single species planted, the maintenance is similar. Common maintenance includes evaluation of soil texture, pH, and nutrient values, proper watering, and mowing at the right height. 

Healthy St. Augustine grass on the fieled

Having both Bermuda and St. Augustine grass means your lawn will be full and flourishing no matter the season. Get familiar with the care requirements for both types of grass. You will need to find balance with some aspects of this care.

For example, a base of St. Augustine grass needs about twice the nitrogen and water versus Bermuda grass. Keep in mind that shade impacts Bermuda grass, while St. Augustine is sensitive to colder temperatures. 

Keep a good balance of each species of grass on your landscape. Stay on top of your lawn by monitoring for any changes, have a maintenance plan, and keep up to date with soil tests. 

Concluding Thoughts

St. Augustine grass thrives in well-aerated, loose, sandy soils. This grass grows best when planted in hot months and well before the first frost of the year. Your soil should be prepped and properly tested before you lay down your sod.

St. Augustine can be mixed with other species of grass, and in some cases, it is recommended. We hope you found this article helpful as you are preparing to lay your own St. Augustine grass on your landscape, and you found plenty of helpful tips.  Get ready to enjoy the dark green, smooth look of this grass. 

Do you want to explore other grass options? Have a look through our blog post, What’s The Best Grass For Shade In The South?

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