What Causes Brown Spots In Your Lawn

Brown spots of dead or dying grass could have several causes. Learn how to identify which one is affecting your lawn so you can restore the health of your turfgrass.

Identifying Causes Of Brown Patches In Lawns

Grubsgrubs in soil

There are two kinds of white grubs we see here in Utah lawns, and both can cause dead brown patches in your turfgrass. One way to tell if it’s grubs ruining your lawn: the brown patches will be irregularly shaped. Unlike brown spot, a lawn disease that we’ll get to shortly, the damage caused by grubs comes in unpredictable, irregular shapes.

The grubs you see are either the larvae of Japanese beetles or billbugs, a type of lawn weevil. Both species use turfgrass as a nursery to feed and protect their young. The eggs hatch beneath the surface of the soil. This occurs in spring when the warmer weather arrives. Once the eggs hatch, they go into their larval stage – what you would recognize as white grubs. These grubs munch the roots of your turfgrass. While having some grubs in your lawn is not the end of the world, an overabundance of the critters is where your lawn runs into trouble.

Aside from the irregularly shaped dying or dead patches, other signs that point to grubs include:

  • Increased activity of birds, possums, or raccoons on your lawn. These animals consider grubs a delicacy!
  • Spongy turf that feels like a running track when you walk on it.
  • Turf that pulls up easily like freshly laid sod

Compacted Turf

It’s natural for your lawn to have some build-up of thatch. Thatch is simply an organic matter that has broken down. Organic matter could include grass clippings from the mower, dead leaves, etc. However, when the thatch build-up is extensive, it can smother grass, leading to brown dead or dying patches. Also, compacted soil is dense, making it difficult, even impossible, for the grass’s roots to spread out and grow properly. To test out your lawn for excessive thatch build-up, try to pierce the soil with a trowel or shovel. If it’s difficult, you could have compacted soil. Luckily, there’s a simple solution: aeration. Also known as “core aeration,” this service uses a specialized tool to gently break up the compacted soil without harming the look or health of your lawn.

Nutrients Imbalancesoil testing by hand

If you have tried adding fertilizer to your soil to correct those brown spots, and your lawn hasn’t repaired itself, it could mean the pH level is out of balance. If your lawn leans to the acidic side of the spectrum, all the fertilizer in the world is not going to make a difference. Acidic soil isn’t receptive to fertilizers. Try performing a soil test and see what the results say. If it’s not the pH level, it could be that one of the macronutrients has been over-applied. Nitrogen is a vital mineral that all lawns need, but it can actually burn the grass and create brown patches when over-applied. Quick-release fertilizers are a common culprit.

Turf Disease

Believe it or not, there is a turf disease called brown patch that, well, causes brown spots in your lawn. The difference, though, is that these spots appear more symmetrical than the other problems we’ve discussed. Brown spot lawn fungus is caused by the Rhizoctonia fungus, and it typically appears during the hot, dry summer months. The affected blades of grass will have lesions that are tan and irregularly shaped. You may also notice white mycelium if you inspect your lawn first thing in the morning.

Foot Traffic

This goes for both humans and animals. Frequent foot traffic by dogs or humans can quickly tear up the turf and result in browned grass.


As weeds naturally die off or get treated with herbicide, they can leave behind bare brown patches of thinned grass or bare exposed soil. To combat this problem, ask your lawn care service provider about patching the bare spots with an overseeding application.

Restore Your Turfgrass With Help From Ferta-Lawn

Get the highest quality lawn care in the Salt Lake City area! From our grub prevention program to our multi-step lawn care applications, the professionals at Ferta-Lawn have the expertise to rid your lawn of brown spots. Don’t put up with that eyesore of a lawn any longer. Give us a call today at 801-295-3057 or contact us online here. And to stay up to date on the latest products, offerings, and deals, be sure to read our monthly blog and like us on Facebook, Instagram, and Pinterest!

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