We get this question a lot in spring and after wet stretches. “There are mushrooms popping up all over my lawn — what are they, and what do I do?” The good news: in almost every case, they’re not damaging your lawn at all. The mushrooms themselves are a symptom of something underground, and once you understand what that is, the right action becomes obvious.
After 40+ years of looking at Maine lawns, here’s what those mushrooms are actually telling you.
What Mushrooms Actually Are
The mushroom you see on the lawn surface isn’t the whole organism. It’s the fruiting body of a fungus that lives entirely underground, the same way an apple is the fruit of a tree you see above ground. The fungus itself is a network of fine white threads (called mycelium) growing through the soil, breaking down organic matter and recycling nutrients.
The mushroom only shows up when the fungus reproduces. That’s why you see them after wet weather, in shaded areas, or in spots where conditions are favorable. They’re not appearing because something is wrong with the lawn. They’re appearing because the underground fungus is doing exactly what fungi are supposed to do.
Why They Appear in Lawns
The fungi that produce lawn mushrooms feed on decaying organic matter. The most common food source on Maine properties is buried wood:
- Old tree stumps that were ground or buried. Even decades after a tree comes down, the root system underground can still be feeding fungi.
- Dead tree roots from trees that were removed years ago. Roots decompose slowly, especially in cooler Maine soils.
- Construction debris. Builders sometimes bury scrap lumber, brush, or stump grindings during site prep. We’ve found stumps under lawns 30 years after the house was built.
- Heavy thatch layers. Decomposing thatch is fungal food.
- Buried compost or topsoil organic matter. Especially on newer lawns where fill was brought in.
If your mushrooms keep appearing in the same spot year after year, it’s almost always one of these. There’s something organic decomposing under that exact location.
Are They Harmful to the Lawn?
The mushrooms themselves don’t damage turf. The fungi underground actually help the lawn in most cases by breaking down organic matter and releasing nutrients into the soil. You’d never want to actually eliminate the underground fungal network even if you could (which you can’t reliably do anyway).
The exception worth knowing about is fairy rings. These are circular or arc-shaped patterns of mushrooms (sometimes 3 to 30 feet across), often paired with a ring of darker green or browned grass. Fairy rings are a specific fungal pattern where the mycelium grows outward in a circle. They’re not damaging in a serious way, but the visual pattern can be persistent and frustrating. Cultural management (deep aeration, watering, balanced feeding) is the right approach. There’s no reliable rescue product for fairy rings.
What to Do About the Mushrooms You See
For typical scattered lawn mushrooms, the management is simple:
- Mow them off. A regular mow knocks them down and they dry out. They’ll come back after the next wet stretch but it’s not a problem worth treating.
- Hand-pick them. If you have kids or dogs and don’t want them coming into contact with the mushrooms, just snap them off at the base and dispose. Rubber gloves if you’re sensitive.
- Skip the fungicide. Fungicide treatments don’t kill the underground mycelium reliably and they’re not warranted for a cosmetic issue. Don’t waste the money.
- Wait it out. The mushrooms disappear when the underground food source runs out. That can take years if there’s a lot of buried wood, but they’re getting smaller as the food breaks down.
If You Have Pets or Kids
Some Maine lawn mushrooms are toxic if eaten. Most are not, but identifying species in the field is hard and you don’t want to take the risk. The simple rule is: assume any mushroom in your lawn is potentially toxic and remove it before pets or kids can get to it.
If a pet eats a mushroom, take a photo of the mushroom and the pet to your vet. Same for kids and your pediatrician. Identification of the specific species is what guides treatment, so the photo matters.
The Source Is Underground
If your mushrooms are concentrated in one specific spot and they keep coming back year after year, you almost certainly have buried organic matter directly underneath. The choices then are:
- Live with it. Mow them off as they appear. Eventually the underground food source will fully decompose and the mushrooms will stop. Could take 5 to 15 years depending on how much wood is down there.
- Dig it out. If you can locate and excavate the buried wood (old stump, debris pile), the mushrooms stop almost immediately. Significant labor for a cosmetic issue, but it’s an option.
- Replace soil and sod the area. Major project. Rarely worth it for a mushroom issue alone.
What Mushrooms Tell Us About Your Soil
A lawn with mushrooms isn’t a sick lawn. It’s almost always a lawn with active soil biology, decent moisture, and decomposing organic matter underneath. That underground activity is good for soil structure, nutrient cycling, and long-term turf health.
What we’d actually be more concerned about is a lawn that has compacted, lifeless, biologically inactive soil. That’s the lawn that struggles, not the one with occasional mushrooms.
If your mushroom situation is bothering you and you want a real read on what’s going on with your soil, that’s part of what our turf management programs include. Soil testing, organic matter assessment, and feeding strategy that supports both healthy turf and active soil biology.
When to Call Us
You don’t really need to call about scattered lawn mushrooms. They’re cosmetic. But if you have:
- Persistent fairy rings that are 6+ feet across and getting bigger each year
- Heavy mushroom flushes paired with dying turf in the same area
- Concerns about toxic species and you’d like an ID
Send us a photo to 207-989-1433 or request a free quote. We’ll take a look and tell you whether it’s something to manage or just to live with.
Jeremy & the Green Thumb Team