There are several potential reasons why your beloved fescue lawn has suddenly developed unsightly brown patches.
The most common reason why fescue grass turns brown is due to brown patch disease, which is caused by Rhizoctonia fungi. Other causes may be if the air temperature is very high and there are high levels of humidity, the soil has become too wet through lack of drainage, and because of drought stress.
This in-depth article will help you:
- Identify the cause
- Fix the problem
- Ensure it doesn’t happen again
Why Is My Fescue Grass Brown?
All grasses are prone to attacks by soil-borne organisms, which will turn the grass brown if they can take hold. Tall fescue is often under attack from various Rhizoctonia fungi that love to feed off seeds and seedlings.
Tall fescue is a type of cool-weather grass. It stresses and lowers its immunity in humid air that exceeds 85°F (29°C).
Humid weather and over-fertilizing will both speed up the spread of fungi and the brown patches that will form above it. Most diseases lay waiting in the thatch-ready to attack when the grass has weak immunity.
Rhizoctonia solani is one of the more common species of fungi that will discolor and damage your grass. Rhizoctonia zeae is another fungus that will cause your tall fescue to turn brown when the weather becomes hot and humid.
Why Does Tall Fescue Turn Brown in the Winter?
Flooding from rain and the thawing of winter snows can cause a buildup of water beneath the turf. Without treatment and good drainage, the flood water will feed fungus growth and help it spread out to the rest of your lawn.
With waterlogged, fungi-infected turf, you may notice the morning dew clinging to a web-like material across the blades of grass.
Signs of fungus growth on tall fescue can be white, burgundy, or dark purple patches and shriveling leaves. But the infected areas will all form circles, and this is also evidence of propagation and the fungi growing out to nearby roots.
Brown Patch vs Dollar Spot
Brown patches tend to show a broader problem affecting the roots and a sign that you need to apply a range of other tricks to save your grass from dying. Brown patches from some diseases will kill the grass if left untreated, but Dollar Spot fungus is less damaging.
Dollar spots will appear as tennis ball-sized patches at random intervals across your lawn. The dollar spot may appear after fertilizer treatments, and you may need to spray a fungicide to prevent it from spreading.
How to Treat Brown Patches in Fescue Grass
The professionals prefer to use alternative prevention methods first. Fungicides are effective at saving seeds, seedlings, and young lawns. But for an established lawn, you should save the powerful commercial fungicides until you see a major problem develop.
Homeowners will not have the same amount of time and money to tend to their lawns. Though a monthly application of fungicide can be effective at preventing brown patches if you are having ongoing issues.
The protection from some fungicides is limited to turf disease, and there is a small window for the best time for them to be sprayed. Some of the chemicals in industrial fungicides are also considered dangerous for use in residential areas.
In desperation, some lawn owners use bleach to kill grass infections. Never use a chemical that does not say it is safe for use on grass. Bleach not only kills the fungus and insects, but it also kills the grass, making it impossible to grow anything in the soil for years.
Granular fungicides are an effective method of preventing fungus growth. The grains of the mix dissolve slower than their liquid counterparts and will not wash out during rainfalls and irrigation.
What You’ll Need
- Weather Forecast – It is better to apply a fungicide when the weather forecast gives you a few days of minimal to no rainfall. You want to give the fungicide time to settle and attack the disease.
- Fungicide – Apply a fungicide every four to six weeks to prevent disease. Use a spreader to ensure that you get even coverage across the lawn.
- Seed Patch Repair – Use a patch and repair seed for tall fescue and a spreader to repair bald spots in your lawn. The mix will also thicken the rest of the lawn and absorb excess water, which causes mold to form on the seeds as they germinate.
Brown patches are harder to save on large swathes of grass, where infections can spread fast. It is more cost-effective to focus on the prevention of fungus on golf grounds and sports pitches than on repair treatments.
The regular application of fungicides after intense rain can help to prevent attacks from fungus and insects.
Commercial sports turf will also go through a vigorous and scheduled maintenance procedure. Groundskeepers trim the grass to within fine tolerances and moderate the pH levels of the soil to within specified limits.
Groundkeepers will also remove anything that creates excessive shade and thatch. All excess water should drain away from the roots to prevent pooling. But most important of all, the level of water in the ground must be enough to feed the grass.
How to Maintain Your Lawn to Reduce Brown Patches
Preventing brown patches from forming on your lawn is preferable compared to a disease that has already done severe damage. But there are a few things you can do to keep your lawn looking healthy and to reduce the chances of brown patches developing.
Fertilizer feeds your tall fescue and enriches the soil with nitrogen and other chemicals to help it fight disease. You need to balance the use of lawn fertilizer by choosing a slow-release brand that gets to the roots and does not cause fertilizer burn.
Each species of grass has a height preference. Tall fescue grows best when mowed to 3-3.5 inches (7.5-9cm). This is the best height for healthy tall fescue and will give it the best resistance to disease and attacks from insects.
Tall fescue grows the best with a weekly rainfall of 1 inch (2.5cm), so keep a record and try to make up the difference with irrigation. Do not overwater as this will drown the roots, rob them of oxygen, and encourage fungi growth.
Other Cultural Practices
Wear aeration shoes when walking over your tall fescue to improve drainage and allow more oxygen to reach the roots. These shoe attachments will also help fertilizers, fungicides, and repair mixes to reach the roots below the turf.
You also want to use a rake to remove thatch from dead grass, which is food for fungi and insects. Thatch is a significant cause of yellow and brown grass and dulls the appearance of an otherwise lush green lawn.