What Causes Mushrooms in My Lawn

Has It Been Raining?

It's a beautiful morning after a long rainy spell. You step outside to check out the yard and there they are: mushrooms have mushroomed overnight. They're under the shrubs. They're over by the tree. They're even smack dab in the middle of the yard. What causes the mysterious—and frustrating—appearance of these strange growths? You can blame it on the right mix of moisture, shade or cloudy weather, and rich, organic material in the soil. When those elements combine, it's mushroom time.

What Are Mushrooms?

Mushrooms are fungi, or rather, the reproductive part of fungi that live in the soil. Most of the time, the fungi just stay hidden, breaking down organic material. But when conditions are right, they burst forth, like desert flowers blooming after a rain. Mushrooms spread spores into the air and then go away when the sun comes out or the soil dries up. 

How to Get Rid of Mushrooms

Prevention is key to controlling mushrooms in your lawn. You can keep mushrooms from appearing as frequently by changing some of the conditions of your yard. It also helps to remember that mushrooms themselves aren't a problem, but the conditions that invite mushrooms can also bring in less friendly lawn fungi. Here's a few steps you can take to get rid of mushrooms in your yard:

Decrease Shade in Problem Areas. Since mushrooms like shade, trim back or thin out branches on nearby trees or shrubs. Extra sunshine helps keep mushrooms in check.

Avoid Compacted Soil. If your lawn has standing water or remains damp for long periods after a rain, your soil may be compacted. Aerating your lawn can help improve drainage, which will, in turn, help decrease the moisture that encourages mushrooms. It also helps to increase the amount of oxygen that gets to the roots of your grass. If you have excess thatch in your lawn (over half an inch), you have a lot of organic material that absorbs moisture and acts as mushroom bait. Dethatching your lawn can also help keep mushrooms away. Learn more about aerating and dethatching here.

Minimize Debris Like Old Trees and Pet Waste. If you have an area where a tree used to stand, even if the stump is gone, the dead roots underground may encourage mushroom growth. If the stump is still there, you can have it removed. If it's gone, just keep the area well raked and aerated to improve drainage. It also helps to frequently clean up after your pet. Animal waste left on the lawn can also bring out mushrooms.

Know That Mushrooms Aren't All Bad. If you have mushrooms, look on the bright side. Mushrooms are an indication that your yard has a lot of organic material in the soil. Mushrooms help break down that organic material and make your soil more productive. If your shade and drainage aren't real problems, you can always just knock the offending mushrooms over and wait for the sun to come out.

Target Less Friendly Fungi. Damp conditions can bring out other types of fungi that can create more serious problems for your lawn. Brown patch, fusarium blight and rust are a few of the diseases that thrive in wet grass. The good news is these lawn diseases can be controlled by fast-acting Scotts® DiseaseEx™ Lawn Fungicide, a broad spectrum disease prevention and control product, or Scotts® Healthy Turf Builder® Fungicide and Lawn Food, which prevents 27 types of lawn disease while feeding your lawn.