Why Is My St Augustine Grass Dying?

If you notice that your once-beautiful St. Augustine lawn is losing its vibrant green color, you must have wondered, ‘Why is my St Augustine grass dying?’ Always remember that whatever problem you are facing is also faced by many homeowners.

Maintaining St. Augustine grass, especially in climates with varying weather conditions, is tasking. But there are ways you can employ to stop it from dying and get your lawn back to looking like its former, beautiful, green self. Read on to find out!


What Does St Augustine Grass look like? 

Why Is My St Augustine Grass Dying?
St Augustine Grass

St. Augustine grass, scientifically known as Stenotaphrum secundatum, is a warm-season grass popular for its thick, lush growth and ability to survive in hot, humid weather. Its blades which are wide and flat give it a coarse texture.  its color ranges from light to dark green.

This grass creates a dense, carpet-like turf often seen in lawns, parks, and other outdoor spaces. It spreads through above-ground stems called stolons, which help it bounce back quickly from any damage. St. Augustine grass thrives best in full sun but can also grow in areas with some shade, making it a flexible choice for landscaping.


Why Is My St Augustine Grass Dying?

These are a few possible reasons your St. Augustine grass is dying, such:

  • Improper watering:

St. Augustine grass needs regular watering, but not excessive watering because overwatering can cause root rot, a condition where the roots decay due to too much moisture. Poor drainage makes this worse, by causing water to gather around the roots and deprive them of oxygen, suffocating them.

  • Improper mowing:

If you cut St. Augustine grass too short, it becomes strained and more susceptible to disease and pests. Short grass cannot photosynthesize efficiently.

Photosynthesis is the process by which plants make food using sunlight, so when the grass can’t photosynthesize well, it becomes weaker and less able to defend against threats like disease and pests. Also, cutting the grass too low can cause the base of the blades to get sunburned.

  • Nutrient deficiency:

St. Augustine grass needs specific nutrients to grow well. If the soil doesn’t have enough of these essential nutrients, the grass can turn yellow and eventually die.

You have to provide them with the right nutrients through fertilization to keep your St. Augustine grass healthy and green.

  • Hard soil:

When the soil is tightly packed, it’s hard for water and nutrients to reach the roots of St. Augustine grass. This can lead to weak growth and, eventually, the grass dying.

To fix this, you can aerate the soil by making small holes in it. This helps loosen the soil, making it easier for water and nutrients to get to the roots.

  • Disease and pests:

Another reason why your St. Augustine grass is dying is because it has been infected by different diseases and bugs, which can make it weaker and eventually die if not fixed quickly. Some common diseases that affect St. Augustine grass are brown patch, gray leaf spot, and take-all root rot.

These diseases can make the grass change color, become thin, and even die if you don’t treat them. Also, insects like chinch bugs, armyworms, and sod webworms eat St. Augustine grass, damaging and possibly killing it.


Read also: How Often Should I Water St Augustine Grass?


What is the Best Fertilizer for St. Augustine Grass?

The best fertilizer for your St. Augustine grass depends on what you want for your lawn. Here are some guidelines to help you choose.

First, how much nitrogen is in the fertilizer? St. Augustine grass needs lots of nitrogen to grow well. For established lawns, look for a fertilizer with 3-4% nitrogen. For new lawns or grass that is still growing, look for up to 6% nitrogen.

Next, think about the levels of phosphorus and potassium. St. Augustine grass does not need as much phosphorus and potassium as it does nitrogen, but these nutrients are still important. Look for a fertilizer that has a balanced mix of nitrogen, phosphorus, and potassium, like a 16-4-8 or 15-0-15 blend.

You also need to decide if you want a slow-release or quick-release fertilizer. Slow-release fertilizers give nutrients to the grass slowly over time, which is better for the grass. Quick-release fertilizers can be good too, but you need to follow the instructions carefully.

Consider micronutrients too. St. Augustine grass might need extra micronutrients like iron, manganese, and zinc, especially if your soil is alkaline. Look for a fertilizer that has these micronutrients in a form that the grass can absorb easily.

Lastly, what form of fertilizer do you want to use? Granular fertilizers are easy to spread and give an even amount of nutrients to the grass. Liquid fertilizers can be absorbed quickly by the grass, but you might need to apply them more often.


Is Too Much Water Bad for St. Augustine Grass?

Yes, too much water can be bad for your St. Augustine grass. Although this grass needs regular watering to stay healthy, too much water can harm it in several ways. One issue is that overwatering can make the grass’s roots start to rot, which will eventually kill the grass.

Overwatering can also lead to the growth of fungus and other diseases that can damage the grass. To prevent these problems, it’s best to water St. Augustine grass deeply but not too often.

This helps the water soak deep into the soil, encouraging the roots to grow deeper and making the grass more resistant to dry spells.


What Can I Do About Yellow St. Augustine Grass?

If your St. Augustine grass is turning yellow, you can take a few steps to fix it and bring back its lush green color.

First, check how you’re watering. Yellowing can mean you’re either watering too much or too little. Water deeply but not too often, letting the soil dry out a bit between waterings.

Next, think about the nutrients in your soil. Yellowing might show that your soil is lacking important nutrients like nitrogen, iron, or manganese. Test your soil to find out what’s missing and use the right fertilizer.

Also, watch out for pests and diseases. Bugs like chinch bugs and diseases like brown patch fungus can make your grass turn yellow. Look for signs of pests or diseases and treat them quickly.

Make sure you’re mowing your grass correctly too. Don’t cut it too short because that can make it strained and cause yellowing. Keep your mower at the right height, around 3-4 inches, to help your grass grow well.

Lastly, if your soil doesn’t drain well, fix it. Too much water around the roots can make your grass turn yellow. Improve your soil’s drainage to stop water from pooling around the roots.


Read also: How To Slow Grass Growth


What is the Best Time of Day to Water St. Augustine Grass?

The best time to water St. Augustine grass is early morning. This allows the grass to soak up the water before it gets too hot and evaporates.

Watering in the morning helps prevent fungus from growing and lets the grass dry out during the day, which reduces the chance of disease.

Avoid watering in the evening or at night because the grass stays wet longer, creating a damp environment that’s perfect for fungus to grow.


How Do I Revive St. Augustine Grass?

To bring your St. Augustine grass back to its green state, try these steps:

Make sure your grass gets enough water. Water deeply but not too often to encourage deep roots. Avoid watering too much, as it can cause root rot.

Use a balanced fertilizer to give your grass the nutrients it needs. A slow-release fertilizer is best for steady feeding.

Keep your grass at the right height, about 3-4 inches, to help it grow well and reduce stress.

Get rid of any weeds that are competing with your grass for water and nutrients.

If your soil is hard, break it up to help water and nutrients get to the roots.

If you have insects or diseases in your grass, treat them quickly to stop them from causing more damage.

If some areas of your lawn are damaged, plant new St. Augustine grass seed to help it grow back.


Frequently Asked Questions

Q. What Does Epsom Salt Do to St. Augustine Grass?
A. Using Epsom salt can boost the health of St. Augustine grass by giving it magnesium, which plants need to grow. But, you need to use Epsom salt carefully, as using too much will damage the grass.

Q. How Do You Fix Bare Spots in St. Augustine Grass?
A. To fix bare spots in St. Augustine grass, start by raking the area to remove any debris. Then, loosen the soil and add a thin layer of compost. Finally, reseed the area with St. Augustine grass seed and keep it well-watered until the new grass establishes itself.


Read also: How To Kill Water Grass In Lawn



Keeping your St. Augustine grass healthy takes effort. You can bring it back to life by fixing watering problems, adding nutrients, and loosening compacted soil.

Regular fertilizing, mowing at the right height, and watering deeply but not too often are key. With proper care, your St. Augustine grass will grow well and make your yard look great.


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