Skip to Content Top

How To Prevent and Treat Brown Patches in St. Augustine Grass

Discover how lawn care professionals treat brown patch disease on St. Augustine grass below! Regular yard maintenance helps prevent brown patch fungus, also known as large patch disease. But what if a yard still gets infected with a brown patch?

What Is a Large Patch?

Large patch is a fungal disease caused by Rhizoctonia solani, affecting warm-season turfgrass from early spring to late fall. It was previously known as “brown patch” before being renamed. Controlling brown patches on warm-season lawns requires the experience and expertise of a professional, as well as the vigilance of the homeowner.

Signs a Lawn Has Large Patch

Before addressing lawn patches, it must first be identified. Collect a sample from the affected area for analysis by lawn care experts. They may also want to visit so they can control the spreading brown patches and apply the proper treatment. Here are some of the signs that warm-season grasses have large patch:

  • Circular patches one to three feet wide
  • Yellow, tan, brown, red, or orange patches
  • Grass blades detach easily from the rest of the plant    

What Causes Brown Patches in St. Augustine Grass?

St. Augustine grass may seem affected by brown patch fungus, lawn requires even more care.

Damp environments create ideal conditions for fungi like the brown patch fungus to grow and spread large patches across the yard. Some of the common causes of a large patch fungal infection include:

  • Overwatering
  • Poor drainage
  • High nitrogen levels
  • Low mowing
  • Thick thatch
  • Excessive shade

7 Steps to Prevent and Treat a Brown Patch: St. Augustine Grass

The best way to control and reduce the impact of brown patches involves several different tasks. Most experts steps to impede and address brown patch disease on St. Augustine grass.

Step 1: Lawn Inspection

During the inspection of grass blades, lawn experts will check for small, irregular, tan spots. Dark-brown borders often accompany these spots, which coincide with deteriorated sheaths near the soil’s surface.

The symptoms of large patches vary depending on the grass type and soil conditions. Typically, the disease leads to circular patches of light brown grass. The affected areas may range from a few inches to several feet. In many cases, the center of the patch may recover, creating a doughnut-shaped pattern.

In favorable conditions for the disease, large portions of the lawn may experience uniform thinning and eventual grass death without a clearly defined circular patch. Lawn care professionals frequently see this pattern in infected St. Augustine grass, especially in shady, high-humidity locations.

Step 2: Water at Set Times

Watering the yard in the late evening leads to a damp lawn overnight. This practice may result in several lawn health issues, especially in cooler months because it encourages the growth of brown patch mold.

To combat large patches, lawn care experts water the lawn in the early morning, ideally at sunrise. This timing allows the grass to dry thoroughly before nightfall.

Step 3: Water the Correct Amount

Watering too much creates a damp environment ideal for brown patch mold. Professionals water a St. Augustine lawn every five to 10 days or when the grass stays dry for a long time. These warm-season grasses are semi-drought tolerant and do well with as-needed watering.

Experienced lawn care experts water St. Augustine lawns deeply—four to six inches down—to encourage growth and healthy soil. However, the necessary amount will vary based on the lawn's drainage capacity.

Step 4: Keep Nitrogen Low in Early Spring and Late Fall

Nitrogen fertilizer promotes lush, green growth. However, it also creates a favorable environment for brown patch fungus. Brown patch fungus proliferates on tender, new growth fueled by a nitrogen-rich setting.

Timing is crucial when fertilizing to prevent brown leaf spots from developing on individual blades of grass. Lawn care professionals apply nitrogen fertilizer in late spring or summer rather than early spring, avoiding early or late applications.

Step 5: Check Drainage and Aerate

Compacted soil impedes good drainage, leading to excess surface moisture on the lawn. Lawn care professionals aerate the lawn annually and maintain a balanced pH for optimal results. This method promotes active root growth and contributes to visually appealing, healthier grass.

Step 6: Leave the Grass Clippings

Lawn experts regularly mow grass to avoid fungus growth. Mowing the yard every ten days to a height of 2.5-3 inches will help avoid too many clippings. This mowing method maintains a well-groomed lawn. However if the homeowner prefers shorter grass, lawn care professionals can increase the mowing frequency.

Professionals stress the significance of managing clippings in lawn care to prevent clumps and excessive thatch buildup. However, with St. Augustine grass, it’s recommended to leave the grass clippings on the lawn. The clippings will decompress and become a natural fertilizer.

Step 7: Apply Fungicide

Using fungicides in the early stages effectively manages brown spots. Lawn experts utilize various fungicide options. They choose fungicides based on local availability and preferred application methods.

Adhering to the recommended application guidelines on product packaging remains crucial. Typically, applying fungicides once or twice a month yields optimal results. Starting fungicide early after detecting initial signs of brown patch fungus enhances its effectiveness.

Brown Patch Fungus Treatment | Heroes Lawn Care

Now that you know how experienced lawn care professionals control and treat brown patches, leave your lawn maintenance to the experts for a healthy, beautiful lawn. Call Heroes Lawn Care at 844-980-LAWN and schedule a free consultation with the best lawn specialists.

Get Started Towards a Greener Lawn