No matter how much time and effort you spend on your St. Augustine lawn, it may appear more like a harvested wheat field than a putting green. Even if you haven’t changed your lawn maintenance routine, your St. Augustine lawn may develop a straw-like appearance. What could be causing this problem? Well, there are several reasons your St. Augustine turfgrass is turning brown and dying. If you know what to look for, you can quickly tackle these problems and turn your lawn back to the dark green it should be.
Why Has My St. Augustine Grass Turned To Straw? (The Short Answer)
The most common causes of your St. Augustine lawn having a straw-like appearance comes down to an issue with watering, nutrients, weather, disease, and pests. Any of these causes or a combination of them can result in St. Augustine lawn grass having a straw-like appearance.
8 Possible Reasons Why Your St. Augustine Grass May Have Turned to Straw
Once you start to notice a change in the appearance of your St. Augustine grass, you want to diagnose the cause quickly. Let’s take a look at the common problems in more detail and what could be causing your lawn to suffer and struggle.
Take All Root Rot
TARR (Take All Root Rot) lawn fungus can be found attached to the roots of turf grass, including St. Augustine, during spring and fall due to the milder weather. The pathogen Gaeumannomyces graminis attacks the roots of turfgrass and completely destroys the parts of the plant that grow below ground.
TARR is visible on the plant’s upper part by the grass blades’ yellowing and withering. This deterioration can start in small areas and give the lawn a patchy appearance. If TARR goes untreated, the lawn will turn brown, and patches will develop and cover the entire lawn. It is common for lawn owners to confuse this problem with underwatering.
It’s important to note that it’s less common to see TARR during the peak of summer or winter as the weather conditions are not right.
White Grubs
Grubs are the larvae of beetles. In the larva stage, the beetle lives just under the surface of the lawn; just the right place to eat the roots. Once your lawn starts to lose its roots, you’ll notice the top turn brown and start to have a straw-like appearance.
If you are suspicious that you may have grubs (read this: Signs of grubs in your lawn), then grab a shovel and remove the top inch or two of dirt from an affected area. If you find a grub, then take a look in another affected area.
Usually, a couple of grubs around the yard isn’t going to make much of a difference to the lawn, but if you find several in a single square foot, then you’ll need to take some action to get rid of them.
Gray Leaf Spot
This is another disease that hits the St. Augustine turfgrass hard. Gray leaf occurs during the mid-summer months. It appears as a spot in the leaf as if it’s been burned. If left to run its course, it can kill your lawn and give it a straw-like appearance.
One thing that can accelerate the growth of the gray leaf spots is nitrogen. So, if you start to notice the spots a week or two after you have fertilized, then your lawn could definitely be infected with gray leaf spot disease.
Chinch Bugs
If you think you have a dry lawn and you’re giving it more water with no effect, then you could have chinch bugs. These pesky little black bugs are most active during the peak of summer out in the sunny areas of the lawn.
If you’re having a problem in the shade, then it’s unlikely to be the chinch bugs, as these guys like the sun. If you see big rings of dead or dying grass that have folding blades and a washed-out color, then you could be dealing with chinch bugs.
Nutrient Levels
Dealing with nutrient levels in your lawn is a double-edged sword. Too much or too little nutrients can be a problem. Over-fertilizing can cause the grass to turn yellow and potentially kill the lawn. Whereas under fertilizing can cause the lawn to brown and die as the lawn doesn’t have enough food. So, hitting the middle of the scale is vital. Review your fertilizing schedule and check which side of the scale you are overdoing.
Poor Watering
Too much watering will suffocate the St. Augustine root of oxygen and nutrients. In addition, the constant moisture can rot the root. Too little watering will quickly lead to the grass dying out and giving a straw-like appearance. So, check your watering schedule then take a look at the dirt below the grass. You’ll want to check the top few inches and make sure it’s holding a bit of moisture.
Cold Weather
A drop in temperature will make St. Augustine go dormant, which is to be expected. But if you have a particularly significant drop in temperature, it could make the grass struggle beyond what it’s used to. So, if you see the lawn changing, then take note of the weather and check to see if you’re experiencing out-of-the-ordinary temperatures.
Too Much Shade
St. Augustine isn’t a grass type that enjoys being in too much shade. As a result, the lack of sunlight causes the plant to work extra hard to stay alive, resulting in unmanageable stress. St. Augustine grass grown in the shade is usually very thin and weak, and it’s only a matter of time before it turns brown and begins to die. So, keep an eye on the level of daily sunlight your St. Augustine lawn gets, keeping in mind that the sun shifts throughout the year.
What To Do To Save a St Augustine Lawn That Is Turning To Straw
Even though these eight problems can make your lawn look like a hay field, there is still hope. Let’s take a look at how you can tackle each of these common issues.
Take All Root Rot Solutions
Taking care of Take All Root Rot requires a five-step process. The first step is to attack the fungus directly with a fungicide. So, grab yourself a chemical fungicide that directly targets TARR.
Once you have treated the fungus, you can move on to topdressing the lawn. Topdressing is the process of adding an inch of compost directly on top of the lawn. For best results, use a mixture of mushroom compost and Sphagnum peat moss in the spring and fall for 2-3 years.
The third step in the TARR treatment is aeration, which works best if done during May-June. The fourth step is to lower the rate of nitrogen. This can be done by increasing the level of other micronutrients and Potassium/Magnesium.
The final stage is to limit the rate of herbicides used in areas with a straw-like appearance. So, you’ll have to stop using targeted weed killer in your yard.
| Stage | Treatment | Comments |
|---|---|---|
| 1 | Chemical Fungicide | TARR Targeting Chemical |
| 2 | Topdressing | Mushroom Compost & Sphagnum Peat Moss |
| 3 | Aeration | |
| 4 | Nitrogen Reduction | Micronutrients & Potassium/Magnesium. Zero Nitrogen |
| 5 | Herbicide Reduction |
Dealing with White Grubs
The most effective way to get rid of white grubs is to use an insecticide. So, take a trip to the gardening store and pick up an insecticide that targets the white grub.
Alternatively, you could give a call to somebody like Trugreen. You’ll find that TruGreen’s prices are very competitive and their treatments very effective.
For grub treatments to work, the insecticide needs to reach below the ground to where the grubs are growing. Make sure you fully read the instructions, apply enough water, and take every precaution.
Gray Leaf Spot Treatment
Gray Leaf Spot treatment is a multi-stage process. Let’s take a look at what you will need to do.
Mow Lower
To reduce the moisture held in the lawn, you want to reduce the cut height as much as you can. Reducing the cut height by ½ inch will reduce the moisture held in the lawn and also help the sunlight reach the crown of the plant.
Cut the Lawn More Frequently
Cutting more frequently will assist by allowing the sunlight to penetrate the lawn and help keep it dryer. Ideally, you want to cut the lawn every 3-5 days.
Bag Clippings
If you have a bag for your lawn mower, then this is definitely the time to use it. Leaving clippings on the lawn will retain moisture and block the sunlight. Additionally, the clippings will compost and add nitrogen to the lawn, which you certainly don’t want.
Reduce Nitrogen
In addition to cleaning up clippings on the lawn, you want to pause your fertilizing schedule. Cutting out the fertilizer (Nitrogen inclusive) will cut out the food source for the Leaf Spot Disease. If you happen to be using a slow-release fertilizer, then this can take 6-8 weeks to dissolve into the soil completely. So, you’ll have to be patient.
Growth Regulator
If all this extra work seems like too much, then a product is available to slow the lawn’s growth. If you have ever wondered why golf courses and places like Disneyland keep their mowing to a minimum, it’s because they use a growth generator to slow vegetation growth.
So, if you want to keep the lawn short and skip the extra cutting and growth, then you can use a regulator.
Reduce Watering
Knocking down the amount of water your lawn gets is the easiest way to reduce the moisture the fungus needs to thrive. Just be careful not to knock it down so much that the lawn starts to struggle with a lack of water.
Treat for Pyricularia Grisea Fungus
Finally, if all else fails, then treat for Pyricularia Grisea Fungus. This is a direct treatment that will target the fungus directly. You can take a trip to the gardening store and collect a chemical treatment.
Getting Rid of Chinch Bugs
One way to get rid of chinch bugs is to keep ahead of them by frequently cutting the lawn. This is another good reason to have a proper fertilizing schedule. Alternatively, you can use a professional or DIY solution to treat the bugs directly. It can be tackled quickly by taking a trip to the gardening store for some chemicals or calling the professionals. Another way to treat this pest is to introduce a predator to dine on the chinch bugs.
Improving Nutrients
Like most things, moderation is key. So, to avoid overfeeding or starving your lawn, a soil test will give you detailed information on the state of your lawn’s nutrient level. The straw-like appearance more commonly comes from lack of feed, but not always, so the test will come in very handy. Once you have the soil test results, you can devise a fertilizing schedule that keeps the nutrients within tolerance levels.
Schedule Watering
Watering is a topic that is more complicated than you would think. Even though there are restrictions in place, you can still end up overwatering and rotting your lawn’s roots.
On the flip side, you could end up underwatering. Underwatering tends to happen because irrigation timers are set too low, insufficient coverage, broken heads, or timers are not working.
As you have already read, too much water can promote fungus growth. So, as I said, watering is complicated. One way to tell if your lawn is getting enough water is to use a moisture tester. This simple tool reads the soil moisture directly and will take the guesswork out of how much water your lawn has. You can pick it up at the gardening store for around twenty bucks.
Too Much Shade
Shade is a tricky one to address. There isn’t much you can do about reducing the amount of shade other than chop down trees and knock down the neighbor’s house. So, if you’re struggling with shade, then switching to an alternate grass type more suited to these conditions could be the solution.
St. Augustine needs about 4-6 hours of sunlight per day and is the most shade-tolerant warm climate grass available, but if the lawn struggles to get this much sunlight, then it might be best to look for a grass that is even more tolerant to the shade.
St. Augustine Grass Turned to Straw Summary Chart
Here’s a quick chart you can use to help identify which of these problems could be causing your St. Augustine to have a straw-like appearance. Just remember that this chart is a general guide, and the seasons will affect when these problems occur.
| Month | TARR | Grub | Chinch | Leaf | Nutrient | Water | Cold | Shade |
| Jan | x | x | x | x | ||||
| Feb | x | x | x | x | ||||
| Mar | x | x | x | x | x | x | x | |
| Apr | x | x | x | x | x | x | ||
| May | x | x | x | x | x | x | ||
| Jun | x | x | x | x | x | x | ||
| Jul | x | x | x | x | x | x | ||
| Aug | x | x | x | x | x | x | ||
| Sep | x | x | x | x | x | x | ||
| Oct | x | x | x | x | x | x | ||
| Nov | x | x | x | x | x | |||
| Dec | x | x | x | x |
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