How To Get Rid of Brown Spots in Grass

How To Find Out What’s Causing Brown Spots in Your Grass

Before you can get rid of the brown spots in your grass, it’s important to know what’s causing them. By following the steps below, you can narrow down the potential culprits and take appropriate action to revitalize your lawn.

1. Examine the Affected Area Closely

Before you try anything else, take a close look at the brown spots, observing their size and shape. Look for any patterns or signs of physical damage. Sometimes, the cause can be as simple as accidental damage. For example, leaving an object on the lawn (like a tabletop, grill, or bench) for even a few minutes can lead to brown spots.

2. Check for Signs of Pest Activity

Inspect the grass blades and soil for insects or their larvae. Look for chewed leaves, sawdust-like insect excrement, or small tunnels in the soil. These signs can indicate an insect infestation.

3. Assess Soil Moisture

Test your soil moisture in both the affected areas and healthy parts of the lawn. Simply feel the soil in different areas with your hands to feel any differences. Dry patches will be noticeable and may indicate irrigation issues. Alternatively, you can ​​use a soil moisture meter to test the soil more accurately.

4. Evaluate Sunlight and Shade Patterns

Observe how sunlight falls on your lawn throughout the day. Note any areas that receive excessive shade or intense sunlight, which could contribute to brown spots. Uneven sun exposure can lead to stress on certain parts of the lawn.

5. Consider Recent Lawn Care Activities

Reflect on any recent lawn care activities, like fertilizer application, herbicide use, or changes in mowing habits. These changes may seem subtle, but they could‌ cause brown spots.

Human/Animal Damage To Your Lawn

Unfortunately, it’s very easy for humans and pets to inadvertently damage lawns. Keep an eye out for some of the causes of lawn damage below:

Dull Mower

Dull mower blades can tear your grass instead of cutting it cleanly, gradually killing your grass. This can result in a brownish appearance across the lawn.

To remedy this issue, sharpen your mower blades in fall and spring. After mowing, examine the grass regularly to see if the mower is cutting cleanly. Clean cuts indicate sharp blades, while ragged edges mean that it’s time for sharpening.

Scalping

If you set the mower blade too low or there are bumps in your lawn, it can cut the grass too short and cause damage, also known as scalping. This exposes the grass stems and can lead to brown patches.

To fix this, raise your mower blades to an appropriate height for your grass type. We recommend setting blades around 3 inches. Additionally, you can smooth out high spots in your yard by digging up the sod, removing some of the soil underneath, then replacing the sod.

Chemicals

Chemicals can cause dead spots if you spill them on your grass. If you fertilize your lawn, make sure to apply it evenly and correctly. Otherwise, it can burn your grass. Even insect repellents can burn the lawn if you spray them directly on grass blades.

To prevent chemical damage, pour chemicals, fuels, and sprays on the driveway, not on the lawn. Follow application directions carefully to avoid lawn fertilizer burn. If you spill any chemicals, immediately flush the area with water to dilute them.

Animal Urine

Dogs are the most common culprit for urine spots, but large birds and other animals can cause them too. Urine burns usually cause the lawn to turn yellow in spots.

To fix this issue, train your pets to use a designated area of the yard. If that doesn’t work, try immediately watering the spots where they urinate to dilute the nitrogen concentration.

Poor Growing Conditions

Not all brown spots are because of damage to your grass. Sometimes, these spots exist because of unfavorable growing conditions in your yard. Keep a close watch for the following causes of poor lawn growth:

Poor Soil

Soil quality can vary across a lawn, and poor soil quality can occur in patches, causing brown, bare areas. To test your soil quality, use a screwdriver to probe the ground. If it doesn’t penetrate easily, it means your soil is compacted, which can lead to poor root growth.

To improve poor soil, aerate and use top-dressing to improve the soil in your lawn. Aeration involves poking small holes into the soil to allow air, water, and nutrients to reach the roots. Top-dressing is when you add a thin layer of compost to your lawn to help the grass grow. Both of these tasks help incorporate nutrients and improve root growth.

Buried Debris

Sometimes, buried objects in your yard can impede grass growth, resulting in mysterious brown patches. While uncommon, it’s worth checking to see if anything buried in your yard may be causing these spots.

To investigate, use a screwdriver or small garden tool to gently probe the soil in and around brown spots. If you find anything buried, remove it and replace the soil and grass.

Erosion

Water tends to run off slopes, taking grass seeds and young shoots with it. This can leave patchy or brown areas on the sloped sections of your lawn.

To combat erosion, aerate the lawn to increase water absorption. For steep slopes, consider building terraces or planting ground cover to stabilize the soil.

Roots

Large trees or shrubs usually win the battle for water and nutrients because their roots grow deeper than the grass nearby. This makes the area under trees notoriously difficult for growing grass, which can lead to brown patches in the lawn near trees.

Consider mulching or naturalizing areas under trees and shrubs where grass struggles to grow. This can improve the appearance of your lawn and conserve soil moisture for the trees.

Drought

Lawns need at least an inch of water per week, either from rainfall or irrigation. If your lawn is dry, it can lead to dead, brown patches.

Keep a close eye on sunny spots, especially if the soil drains poorly. Make sure to water your entire lawn evenly if you’re using an irrigation system.

Dormancy

Cool-season lawns (like Kentucky Bluegrass, Fescues, Bentgrass, etc.) can go dormant during the heat of summer, while warm-season lawns (like Bermudagrass, Centipedegrass, Zoysiagrass, Bahiagrass, etc.) go dormant during winter. If your lawn has a mix of grass types, you may see brown patches as some areas go dormant while others stay green.

While seasonal dormancy is normal, make sure to fertilize, water, and mow your lawn throughout the growing season to help the grass better withstand dormancy periods.

Common Lawn Diseases and Pests

Once you rule out all the causes above, you may need to consider more serious diseases and pests that plague lawns. Here’s a list of some of the most common diseases and pests that may be hurting your lawn:

Thatch

Thatch is a buildup of decaying grass blades that can become so thick it chokes out healthy grass. Excessive thatch can prevent water and nutrients from reaching grass roots, leading to brown patches.

To address thatch issues, remove buildup if it’s more than a half-inch thick. Dethatching your lawn can be difficult with a rake, so consider using a dethatcher attachment for a lawn mower to make it easier.

Grubs

Grubs are a common problem in the summertime. These larvae feed on grass roots, causing brown patches that can quickly expand. One of the biggest symptoms of a grub problem is when sod easily pulls back from the ground like a carpet.

To check for grubs, pull back a section of sod and inspect for fat, white curved worms. More than ten per square foot can cause lawn damage. If grubs are present, apply a grub control product to exterminate them.

Chinch Bugs

Chinch bugs are a common summer pest for warm-season lawns, especially in hot, sunny patches beside driveways and sidewalks. These small insects suck the sap from grass blades, causing them to dry out and turn brown.

To identify chinch bugs, inspect the lawn closely, paying attention to the border between damaged and healthy grass. Look for small black and white bugs on your shoes when walking through the grass. Chinch bugs are resistant to many pesticides, so if you see them, use specialized products to target them.

Fungal Diseases

Brown patch disease and other fungal diseases thrive in moist conditions, often appearing in midsummer or spring. These diseases may cause circular or irregular brown spots or a general thinning of the grass.

To manage fungal diseases, increase air circulation and sunlight exposure to make the lawn less hospitable to fungi. If that doesn’t work, take a sample of the affected lawn (including blades, roots, and soil) to a local cooperative extension office for analysis. They can suggest appropriate fungicides if necessary.

Final Thoughts About Brown Spots in Grass

Like many problems, it’s easier to prevent brown spots on your lawn before they start than it is to fix them once they’re there. Taking proactive measures can keep your lawn healthy and spot-free. 

Remember, a healthy lawn is the best defense against many of the causes of brown spots. With regular maintenance, proper watering, and attentive care,  you can prevent and manage lawn problems before they become a bigger issue.