What is Summer Patch and How Do You Get Rid of It?

dry patch of missing grass in a yard

Are brown spots covering your lawn? It might be summer patch disease… or it could be drought, heat stress, or brown patch disease? Summer patch resembles the symptoms of many lawn stressors, but that doesn’t make the disease impossible to identify. Our handy summer patch guide will show you how to best diagnose the turfgrass disease and how to get rid of it. 

How to identify summer patch

Summer patch’s wilted grass and tan circles are a common symptom of other lawn diseases and turf injuries. For the most accurate diagnoses, a qualified diagnostician should examine the diseased turf with a microscope

You can send a sample of the infected turf to a diagnostic lab or turfgrass pathology lab. These labs specialize in the accurate diagnosis of turfgrass disease and are often located at state universities. 

So what does summer patch look like on the lawn? Here are the symptoms to look for: 

  • Summer patch appears as crescent-shaped or circular patches of slow-growing, wilted, thin grass. 
  • Sometimes the patches contain healthy grass in their center, giving them a frog-eye appearance. 
  • The patches range from a few inches to 3 feet in diameter but can appear larger when they merge. 
  • Affected grass blades turn reddish-brown, then tan, then a light straw color. 
  • Roots, rhizomes, and crowns are black and rotten.

What causes summer patch in the yard?

Summer patch is a turfgrass root disease caused by the pathogen Magnaporthe poae. The early stages of the disease are rarely visible. Symptoms eventually appear during summer when the infected roots struggle to support the grass blades during drought and heat stress. By the time symptoms of summer patch begin to appear, the roots are already damaged. 

Will summer patch strike your lawn? Here are conditions that encourage the disease: 

  • Soil pH is 6.5 or greater
  • Soil temperatures exceed 65 degrees Fahrenheit
  • Soil compaction
  • Poor drainage
  • Heat stress
  • Drought stress
  • Excessive nitrogen fertilizer
  • Low mowing heights
  • Heavy rainfall followed by extended periods of high temperatures
  • Excessive thatch buildup
  • Watering too often and for short periods
  • Weak root system

How to get rid of summer patch

The best way to control summer patch is with lawn care practices that relieve stressors and increase root strength. Why? Because heat stress, drought stress, and a weak root system often trigger summer patch outbreaks. 

Fungicides are available for summer patch control, but they are more effective as a preventative treatment. Fungicides might attack the fungus, but they won’t alleviate your lawn from cultural stresses or strengthen the turf’s roots. Your grass will have a much smoother recovery if you prioritize your lawn care routine. 

Perform the following treatments on your lawn to help get rid of summer patch: 

  • Aerate compacted soil.
  • Raise your mower blades to your grass type’s highest recommended mowing height.
  • Test your soil and create a balanced fertilizer regime.
  • Avoid fertilization practices that encourage top growth at the expense of root development. 
  • Water your lawn in the early morning before 10 a.m. Avoid watering the lawn in the evening. 
  • Water the lawn less often and for long periods. 
  • Dethatch the lawn.
  • Reseed affected areas with cultivars resistant to summer patch.
  • Maintain a soil pH between 6.0 and 6.5.
  • Minimize soil compaction by redirecting foot traffic.

How to prevent summer patch in the yard

Summer patch attacks lawns that are under stress and have weak root systems. A weak root system often develops because the yard isn’t getting the maintenance it needs. Poor fertilization, bad watering habits, and mowing too low will hinder the lawn from developing strong roots. 

The best way to help your grass establish a deep root system is to maintain your grass. The extra yard work might not sound so appealing, but proper maintenance also will help your lawn fight off other turfgrass diseases. 

The following 15 lawn care treatments will help your lawn grow healthy and strong, making it more resistant to summer patch and other diseases: 

  • Remove leaves and other debris from the yard. Lawn debris provides an excellent place for fungus to remain dormant. A thick layer of leaves also can harm your lawn by blocking the turf’s access to sunlight. 
  • Mow the grass regularly (and correctly). If you mow too low, you risk scalping your lawn. Scalping is stressful for your turf, and it makes your lawn vulnerable to summer patch. And remember, never remove more than ⅓ of the grass blade during a single mow. 
  • Leave behind grass clippings. Your neighbor might bag grass clippings to maintain aesthetic appeal, but grass clippings are healthy for your lawn. Grass clippings help retain moisture and add nutrients to the soil. However, if your grass clippings are infected with disease, it’s best to remove them to avoid spreading the disease. 
  • Perform proper irrigation practices. How you water your lawn has a significant impact on its roots. Watering too often for short periods promotes a shallow root system. Watering less often for long periods encourages a deep root system. Remember to water early in the mornings before 10 a.m. 
  • Invest in a sprinkler system. If you haven’t got time to water your lawn, an automatic sprinkler system might be just what you need. A sprinkler system delivers the right amount of water for your turf and sprays the water uniformly throughout the lawn. 
  • Plant grass seed that’s disease-resistant and suitable for your lawn. Not every grass type will grow well in your yard. Talk to a local lawn care professional about whether you should grow warm- or cool-season grass and which disease-resistant varieties are the best choice for you. 
  • Test your soil. The healthier your soil, the healthier your lawn. A soil test reveals what nutrients your soil is lacking and how you can improve its fertility. 
  • Fertilize your grass. After performing a soil test, implement a fertilization regime that meets your lawn’s nutritional needs.  
  • Aerate compact soil. Core aeration relieves compact soil by creating small holes in the ground. Aeration allows water, nutrients, and oxygen to access the root system. 
  • Remove thatch that exceeds ½-inch thick. Thatch is the dead organic matter that accumulates between the turf and soil surface. A thin thatch layer is healthy for the lawn, but a thick layer may harbor dormant fungus. 
  • Overseed the lawn. Routine overseeding keeps the turf dense and green. 
  • Remove existing weeds. When weeds take over the lawn, your turf must compete for space, nutrients, sunlight, and water. This competition is stressful on your turf. Remove existing weeds with a post-emergent herbicide or pull them by hand. 
  • Apply pre-emergent herbicide. Pre-emergent herbicides help prevent weeds from growing. They are not an ideal herbicide for existing weeds. 
  • Control grubs and other pests. Grubs live underneath the soil’s surface, munching on the turf’s roots. These pests are stressful for your turf and can make your lawn more vulnerable to disease. 
  • Spread compost across the lawn. Compost is a nutritional organic fertilizer. You can rake a compost top dressing across the yard or brew a compost tea and spray it on the grass.  

FAQ about turfgrass disease

1. What grass types are most susceptible to summer patch?

If you grow annual bluegrass, Kentucky bluegrass, or fine fescue, your lawn is highly susceptible to summer patch. Grasses with high resistance to summer patch include creeping bentgrass, perennial ryegrass, and tall fescue. 

2. What other turf diseases can infect my lawn?

Summer patch isn’t the only disease that can turn your lawn upside down. When your lawn starts developing different colors and textures, the culprit may be a fungal disease. Several turfgrass diseases can infect your lawn, including: 

Anthracnose
Brown patch
Dollar spot
Fairy ring
Gray snow mold 
Leaf spot and melting-out 
Pink snow mold 
Powdery mildew
Red thread
Rust 

3. What if I can’t identify the fungus on my lawn?

Correct identification of a lawn fungus is essential for effective treatment. If you misidentify the disease, your control efforts may prove futile. Control methods that work on one kind of disease aren’t guaranteed to work against other diseases. 

Many turfgrass diseases share similar symptoms, which can make identification especially difficult. Contact a local diagnostic lab or turfgrass pathology lab to receive an accurate diagnosis of your infected turf. 

Leave the fungus to the pros

You always dreamed of having a big yard for your family to enjoy, but who knew it would take so much work to maintain? Skipping the lawn chores might save you time, but it’s only going to make your lawn vulnerable to unsightly diseases. And who wants to enjoy the outdoors when the grass looks ugly?

Take back your free time and keep your lawn healthy by hiring a local lawn care professional. A lawn care pro can tackle existing lawn diseases while also preventing future outbreaks. Hiring a qualified professional allows you to prioritize friends and family over a fungus. 

Main Photo Credit: pxfuel

Jane Purnell

Jane Purnell is a freelance writer and actor in New York City. She earned her B.A. from the University of Virginia and enjoys a warm cup of French press coffee.