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7 Reasons Why Bermuda Grass Turns Brown & How to Fix it

7 Reasons Why Bermuda Grass Turns Brown & How to Fix it

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Why does Bermuda grass turn brown? 

Bermuda grass turns brown for the following reasons: Soil compaction, cold spells, or growing in the shade, which slows down photosynthesis. Other reasons are fungal infections such as leaf spot, dollar spot, spring dead spot, and brown patch disease.  

1. Soil compaction

When your soil is too compact, the roots will suffocate. A lack of oxygen and poor drainage rots the roots, killing Bermuda grass

To prevent soil compaction, Bermuda grass lawns need aerated. 

It is possible for brown patches or rings of brown to appear on your lawn when it lacks water. Thatch stops water penetrating deep into the soil. Prevent thatch build up by dethatching your lawn once per year in early spring. 

As soil compaction causes the grass to dry up faster, creating brown patches, you can revive it faster by hand sprigging Bermuda grass, which is essentially growing new grass blades through propagation. 

2. Temperatures below 55 Fahrenheit 

Being a warm-season grass, Bermuda grass goes dormant in the winter. When it’s in dormancy, the grass goes brown naturally. Usually at the end of fall, then greens up in early spring. 

Soil temperatures below 55 Fahrenheit are when the grass goes dormant.  It greens up in spring, thriving when soil temperatures are continuously hovering around 65 Fahrenheit and warmer. 

If there’s an early cold snap either in spring or fall, Bermuda grass can go into dormancy earlier than expected.

3. Lacking sunlight

When growing in shade, such as under the canopy of bushy plants, it’s a good idea to mow at a higher height to help the grass capture more light and retain heat. 

The downside to long grass blades is that the sunlight gets blocked on the lower portions of the grass sprigs. 

Bermuda grass sprigs lacking sunlight exposure will be brittle. You can find longer blades growing in dappled sunlight are elongated, with the lower portion of the leaves turning brown. 

There are times when Bermuda grass just won’t grow. One of those is when you’re trying to grow grass under pine trees or similar plants that put out a huge canopy, shading the grass. 

Bermuda grass needs six hours of full sun daily to all parts of the grass. Blades longer than 2 inches crowds out the lower part of the grass, causing it to brown from the bottom up. 

Mowing it to expose the browning parts to sunlight helps it recover. 

Regular mowing keeps Bermuda grass from browning 

During peak growing season, good lawn care for Bermuda grass is frequent mowing at precise heights. 

Ideally, the grass should be kept between an inch to 2-inches.

When sunlight is scarce, keep it around 2 inches. When sunlight is plentiful, mowing twice weekly to keep the height controlled at a height under 2-inches prevents the grass getting too long that the lower portion of the grass sprigs turn brown. 

Diseases that cause Bermuda grass to turn brown 

Symptoms of the disease is when the browning spreads, or you get brown spots that get bigger. Irrigation problems cause browning only in the area that’s struggling to get water. When it’s spreading, it’s more likely a fungal infection. 

4. Brown patch disease

Brown patch is a fungal disease. Not a description of a symptom, like the name suggests. It’s caused by the fungal pathogen Rhizoctonia.

It’s particularly problematic on warm-season grasses, including Bermuda grass, Zoysia, and St. Augustine.

More so in early spring and late fall when temperatures suddenly spike upwards of 70 Fahrenheit at night. 

Bermuda grows best when the nighttime temperature is above 60 Fahrenheit. Combined with high daytime temperatures, it keeps the soil temperature at 65 Fahrenheit and higher. 

When night temperatures climb to between 70 Fahrenheit and 90 Fahrenheit, that’s when the Rhizoctonia fungus can get out of control. 

If the spread is severe, it may require a fungicide treatment, preferably with a liquid fungicide rather than granular.

Fungicides to treat brown patch disease on Bermuda grass include:  

  • Immunox 
  • Daconil
  • Rubigan
  • Rimidin

Spot treating with fungicides should be done once per fortnight, but treatments aren’t cheap. It’s approx. $20 per 1,000 sq ft. 

Given the nature of fungicides requiring precise applications and dosages, hiring a licensed landscaper with experience treating brown patch disease would be worth considering. 

5. Dollar Spot

Dollar spot causes brown spots on Bermuda grass. It’s a soil-borne fungus infection that’s easier to prevent than it is to get rid of. 

The problem that lets dollar spot set in is when the roots are dry, but the morning dew and moist air on the grass essentially rots it from the top down. 

Preventing dollar spot is done using a fertilizer high in nitrogen. That should be done monthly anyway. It’s one of the reasons each of the best fertilizers for Bermuda grass has high nitrogen levels.

Additionally, steps must be taken annually to ensure water reaches the roots. Do that by dethatching in early spring and core-aerating the lawn – piercing holes in it.  

6. Leaf spot 

Leaf spot on Bermuda grass starts as tiny brown spots on the leaves, but if it’s not treated, symptoms worsen, causing the grass to wilt, turn yellow, and eventually turn brown when it’s dying. 

The fungus Helminthosporium is the cause, and it’s most problematic during a wet spring when the temperatures are just below 65 Fahrenheit. At that temperature and time of year, the grass comes out of dormancy. 

Thatch is a contributing factor to its development, which is why it’s beneficial to dethatch in early spring. Similar to dollar spot, leaf spot is easier to prevent than it is to treat. 

7. Spring dead spot 

Spring dead spot is a fungal disease that only appears in highly maintained lawns. The more care you take with fertilizing, the more appealing it is to this fungal disease. 

Identifying it is easy. It causes brown circles on Bermuda grass. Depending on the severity, it can look like a bleaching effect. 

Where you see brown spots, pick a sprig of grass to inspect it. Spring dead spot rots every part of Bermuda grass. The rhizomes (underground roots), crowns, stems, and stolons (the above-ground runners). 

Effectively, what’s brown on top will be black rot below the surface. It’s only prevalent in the spring and in nitrogen-rich soil. 

When this occurs, the grass can’t outcompete weeds, so you’re likelier to see weeds sprouting up within the brown patches of dead or dying Bermuda grass. 

Treating spring dead spot in Bermuda grass is a balancing act between fertilizer application rates throughout the growing season and applying a fungicide in late fall when the grass goes dormant.

Recovery is slow because you’re essentially stopping the spread of fungal spores while encouraging new grass growth to replace the damaged patch of brown Bermuda grass. 

Frequently Asked Questions related to why Bermuda grass turns brown

Is it normal for Bermuda grass to be green on top but brown underneath? 

When Bermuda grass is above two inches, the top of the grass sprig crowds out the stem underneath. That’s why when you brush your hand across Bermuda grass, you’ll see the stems are brown. It needs kept mowed to 2-inches maximum for sunlight to reach all parts of the grass. 

Does Bermuda grass need top dressing? 

Top dressing with either compost or an organic soil mix helps prevent heat stress causing brown patches on your lawn. It’s common in the peak of summer when the soil struggles to retain moisture. To treat dry brown patches caused by heat stress, rake in a half inch of organic compost or soil.