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Brown Spots in Grass: Identification and Prevention

Your lawn could have brown spots for a variety of reasons—fungus, excessive thatch, and poor soil quality, to name a few. We’ll show you how to identify, repair, and prevent brown spots.

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No one wants unsightly brown spots taking over their once-green stretch of lush, green lawn. But in order to solve this problem, you have to know exactly what you’re dealing with. There are multiple causes of brown spots, from poor soil quality to dog urine and over-fertilization. But don’t fret. This Old House will show you how to identify the brown spots in your grass, repair them, and prevent them.

Once you’ve taken care of your brown spot, This Old House Reviews Team recommends hiring a professional lawn care company to handle all of your lawn care needs to keep your grass hardy and robust. TruGreen offers five annual plans with options like overseeding and aeration that can help you avoid brown spots. To get a free quote, call 866-817-2287 or fill out this easy form.

What Causes Brown Spots in Grass?

In order to combat brown spots, you first have to figure out just what is causing them. There are multiple sources for brown spots, and they must be dealt with in different ways.

Grubs

Grubs are plump, white beetle larvae that can do serious underground damage by eating roots. Their feeding habits can lead to uniform, sponge-like brown spots in your grass. There are several natural at-home remedies for treating grubs, like introducing beneficial nematodes or milky spore. Luckily, lawn care companies like TruGreen offer grub control, so you don’t have to do any guesswork.

Brown patch disease

Brown patch disease is caused by the fungus Rhizoctonia. This disease causes patches of dead brown grass in hot and humid weather, especially in mid-to-late summer.

Brown patch creates yellowish-brown irregular circular patches in your lawn, surrounded by a smoke ring border. Usually, the grass within the smoke ring border simply thins out. But sometimes, the grass inside of the ring gets killed off entirely. Luckily, grass that simply thins out can recover without chemicals.

There are a variety of reasons your lawn may develop Brown patch, including high heat and humidity, excessive nitrogen, moisture, poor soil damage, too much thatch, and compacted soil. In some cases, you can’t prevent your lawn from developing Brown thatch—after all, you can’t control the weather. But you can take some steps to make it less likely.

Apply fungicide

While most lawns recover without chemical intervention, in some cases you may need to combat Brown patch with chemicals. This is best left to professionals. Different fungicides will start showing results at different times. For some, you may see improvement in as little as 24 hours.

Water properly

Excessive moisture can lead to Brown patch, so be sure to water your lawn either early in the morning before 10 a.m., or between 4 p.m. and 6 p.m. to ensure that the grass dries out fully before nightfall. If you allow your grass to remain wet all night, it will become more susceptible to disease and pests.

Fertilize carefully

Too much nitrogen can lead to Brown patch. Try to avoid fertilizing your lawn when it’s hot and humid out, and select a fertilizer with a suitable NPK value. NPK refers to the proportions of nitrogen, phosphorus, and potassium in the fertilizer. You can ask your local gardening store about which fertilizer may be best for your lawn.

Improve air circulation in your soil

Aerating and dethatching will reduce humidity, making it less likely that Brown patch will develop. Aerating is done using a core aerator or spike aerator, either pulling many little plugs or “cores” of soil out of the ground, or perforating it with many small holes. Dethatching, done with a dethatching rake, removes a layer of organic material that can smother grass. When you aerate and dethatch, you allow the grassroots to access the water, air, and nutrients they need more easily.

Thatch

Thatch is the accumulation of dead and decomposing organic material nestled between grass blades and the root system. A little thatch can be a good thing, but a layer over ½ inch thick can choke the grass by preventing the flow of air, water, and nutrients and make your lawn more susceptible to pests and diseases.

You can fix this issue by dethatching or aerating your lawn. You can dethatch your lawn using a dethatching rake to break up the layer, which you can rent or buy from your local garden store. Make sure the settings are appropriate for your grass type.

Aerating your lawn involves poking a series of tiny holes into your soil to let it breathe. There are different types of aerators available for purchase or rent, with the most popular being a core aerator. This type of aerator removes tiny plugs of soil to create room for the flow of nutrients, water, and air into your soil.

Improper mowing

If your mower blades are dull, they tan tear up your grass instead of cutting it cleanly. Shredded, damaged grass will die, and can cause brown spots. To avoid this, sharpen your mower blades in spring and fall.

Scalping is another issue. Even if your mower blades are sharp, you can do some damage—cutting your grass too short can create brown spots in your lawn. Raise your mower blades and be sure you’re only cutting a third of the grass blades at a time.

Too much fertilizer

Excessive nitrogen can cause unfortunate brown spots. Do not overfeed your lawn by fertilizing more often than is recommended, and do not fertilize on hot days.

Poor soil quality

Poor soil quality can lead to brown, bare patches. Try pushing a long-head screwdriver six inches into your soil. If you meet too much resistance, try aerating and covering the area with top-dressing to add beneficial organic matter.

Soil erosion

Combat soil erosion by aerating—this will increase water absorption and help your grass from drying out.

Pet urine burns

Urine from animals like dogs can create brown spots in your lawn, since it’s high in nitrogen. These brown spots have brown centers surrounded by dark rings. The best way to resolve this is by raking up as much of the patchy areas as possible and covering the areas with topsoil, then spreading some grass seeds. Water the area daily for two weeks to promote growth.

Dormancy

Your grass will turn brown when it goes dormant. Warm-season grasses go dormant in the winter, and some cool-season grasses may as well. If your lawn is in a transition zone and made up of different types of grasses, some spots may turn brown before others.

Professional Lawn Care

This Old House Reviews Team’s top recommended lawn care provider, TruGreen, can help you establish and maintain a healthy lawn that’s less susceptible to developing brown spots by handling aeration, fertilization, overseeding, soil amendments, and more.

TruGreen offers five annual plans and a variety of a la carte services in every state except for Alaska. To get a free quote, call 866-817-2287 or fill out this easy form.

Frequently Asked Questions

How do I fix brown spots in my lawn?

You can fix brown spots in your lawn by raking up the dead grass and sprinkling some seed, or implementing proper lawn care regimens—like watering, mowing, and fertilizing properly.

Can grass recover from Brown patch?

In most cases, grass suffering from Brown patch will recover on its own. In some cases, you may need to apply a fungicide.

Can a brown lawn be saved?

Generally, yes. If the lawn is brown because it has gone dormant, it will bounce back by itself and turn green again during its growing season. However, if your lawn has turned brown all over due to drought, there is no way to revive it.

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