Why Are Mushrooms Growing in My Garden? Causes, Risks and What to Do
Why mushrooms are growing in your garden, lawn and mulch after rain, whether they harm your plants, pets or children, and how to get rid of mushrooms or keep them under control.
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If you are wondering why mushrooms are growing in your garden, the short answer is: your soil is alive. Mushrooms growing in your garden are the fruiting bodies of fungi that break down buried wood, roots, thatch and other organic matter. They pop up after rain, especially in late summer and fall.
Most mushrooms in the garden are harmless to plants and even help recycle nutrients. But some are poisonous, and a few types in mulch can stain your siding or car. This guide explains why mushrooms are growing in your garden, lawn and mulch, which ones need attention, and how to get rid of mushrooms safely when you want them gone.
Why Are Mushrooms Growing in My Garden?
Mushrooms are only the visible part of a fungus. Most of the organism lives underground as a network of fine threads, called mycelium, that feeds on organic matter. When conditions are right, it sends up mushrooms to spread spores. The most common reasons for mushrooms growing in your garden are:
| Cause | What is going on |
|---|---|
| Wet weather | Several days of rain or heavy watering trigger mushrooms to appear, often overnight |
| Buried wood and old roots | Fungi feed on stumps, roots of removed trees and buried construction lumber |
| Thick thatch | A layer of dead grass stems in the lawn gives fungi food and moisture |
| Fresh mulch and compost | Wood chips, bark and compost are ideal food for many fungi |
| Shade and poor drainage | Damp, shady spots stay moist longer, so mushrooms last longer |
| Healthy tree roots | Some fungi live in partnership with tree roots and fruit near trees every year |
Mushrooms growing in your garden in fall are completely normal. Cooler nights, rain and falling leaves create ideal conditions for fungi.
Common Mushrooms in the Lawn and Garden
If you are asking “what are these mushrooms growing in my garden?”, these are the types you are most likely to see. Use this only as a general guide, never to decide whether a mushroom is edible:
| Type | What it looks like | Where you find it |
|---|---|---|
| Fairy ring mushrooms | Small tan caps in a circle or arc | Lawns, after rain |
| Inkcaps | Bell-shaped caps that dissolve into black liquid | Lawns, mulch and compost |
| Puffballs | Round white balls that release a cloud of spores when old | Lawns and beds |
| Small brown mushrooms | Thin stems and brown caps; many look alike | Everywhere after rain; some are poisonous |
| Stinkhorns | Orange-red horns with a strong smell | Wood mulch |
| Bracket fungi (conks) | Shelf-like growths on wood | Stumps, dead wood and tree trunks |
Many poisonous mushrooms look like edible ones. Never eat mushrooms growing in your garden unless an expert has identified them.
Are Mushrooms in the Garden Harmful?
For your plants and lawn, almost never. Extension services agree that most fungi in lawns and beds do not attack plants. They break down dead material and return nutrients to the soil.
- Mushrooms in lawns after rain
- Mushrooms and slime molds in mulch
- Puffballs and small brown mushrooms in beds
- Mushrooms growing on the trunk or roots of a living tree, which can signal wood decay
- Dead, brown rings in the lawn from fairy ring fungi
- Black specks on siding or cars from artillery fungus in mulch
For people and pets, the risk is real: some garden mushrooms are poisonous. That is the main reason to remove them where children and dogs play. See pets and children below.
Mushrooms in Lawn: Why They Appear After Rain
Mushrooms in lawn areas usually appear after a few days of wet weather and disappear within days once the sun comes out. They are often a sign of:
- Decaying roots or stumps of trees that were removed years ago.
- Thatch, a spongy layer of dead grass stems at the soil surface.
- Overwatering or poor drainage, which keeps the soil damp.
- Shade from trees or buildings.
Mushrooms in lawn areas do not damage the grass, and mushrooms in lawn soil near old trees can return every year. Mow or pick them off, water deeply but less often, and aerate compacted areas. Our guide on how often to water your garden explains how to water without keeping the soil constantly wet.
Fairy Rings: Mushrooms in a Circle
A fairy ring is a circle or arc of mushrooms, dark green grass or, less often, dead grass. It forms when a fungus grows outward from a central point, often an old stump or buried wood.
- Dark green ring: the fungus releases nitrogen as it breaks down organic matter, so the grass grows faster there.
- Ring of mushrooms: appears after rain, usually in summer and fall.
- Dead or brown ring: a dense mat of fungal threads can repel water, so the grass above it dries out.
Fungicides are not effective against fairy rings. Core aeration, deep watering of the ring and a balanced fertilizer help mask the symptoms. In severe cases, the affected soil can be dug out and replaced.
Mushrooms in Mulch: What Grows There
Fresh wood chip and bark mulch is one of the most common places to find mushrooms in the garden. The most frequent types of mushrooms in mulch are:
| Fungus | What it looks like | Harmful? |
|---|---|---|
| Stinkhorn | Orange-red, horn-shaped, 4 to 8 inches tall, with a strong odor | No, just unpleasant |
| Slime mold | Yellow or orange foam, often called dog vomit fungus | No; it dries up and disappears |
| Bird’s nest fungus | Tiny cups about 1/4 inch wide with egg-like spore packets | No |
| Artillery fungus | Tiny black specks that stick to siding, windows and cars | Not to plants, but the stains are hard to remove |
| Puffballs and inkcaps | Round puffballs or bell-shaped caps that turn to black liquid | No |
- Rake or turn the mulch so it dries out; fungi need constant moisture.
- Keep mulch 2 to 4 inches deep; thicker layers stay wet and invite fungi.
- Replace mulch near the house if artillery fungus stains siding, and consider a coarser mulch or stone in that strip.
Mulch is still one of the best ways to prevent weeds; see our guide on how to get rid of weeds.
Mushrooms in Garden Beds, Raised Beds and Pots
- Garden beds and raised beds: mushrooms often appear after you add compost or wood-based soil. They are a sign of active soil life and do not harm vegetables or flowers.
- Containers: small yellow or brown mushrooms in pots usually mean the potting mix stays too wet. Let the top of the soil dry between waterings and check the drainage hole.
- Near the vegetable garden: remove mushrooms before harvest so they cannot be confused with edible crops.
Building a new bed? Our guide on how to build a raised garden bed explains which soil mix to use.
How to Get Rid of Mushrooms in Your Garden
Wondering how to get rid of mushrooms growing in my garden for good? You cannot get rid of mushrooms permanently without removing what they feed on, but you can keep them under control:
Clearing leaves in fall is quicker with the right tool; compare options in our best leaf blowers guide. Gloves protect your hands when you pick mushrooms; see our gardening gloves guide.
How to Prevent Mushrooms from Coming Back
- Avoid frequent, light watering; water deeply and let the surface dry between waterings.
- Dethatch or aerate the lawn when the thatch layer is thicker than about half an inch.
- Remove stumps and large roots when you take down a tree.
- Use aged compost and mulch rather than fresh wood chips near the house.
- Rake fallen leaves from the lawn in fall, and use them as mulch in beds instead.
Fungicides are not recommended for mushrooms in lawns and beds. They do not reach the fungus deep in the soil, and mushrooms are rarely a problem for plants.
Mushrooms Growing Near Trees: When to Worry
Most mushrooms in the lawn around a tree are harmless and feed on dead roots or live in partnership with the tree. Pay closer attention when you see:
- Mushrooms or shelf-like conks growing directly on the trunk or at the base of a living tree. They can be a sign of wood decay inside the tree.
- Mushrooms together with cracks, dead branches or a leaning trunk.
- Honey-colored mushroom clusters at the base of a declining tree, which can point to root rot.
In those cases, ask a certified arborist to check whether the tree is still safe, especially if it stands near the house, a path or a play area. Mushrooms in lawn areas away from the trunk are rarely a concern.
Mushrooms, Pets and Children: Stay Safe
- Treat all wild mushrooms as poisonous. Many toxic species look like edible ones.
- Check the yard after rain and remove mushrooms before children or dogs go out.
- Dogs are especially at risk because they eat things off the ground. If your pet eats a mushroom, call your veterinarian or an animal poison control line right away.
- Children: if a child eats a wild mushroom, contact Poison Control (1-800-222-1222 in the U.S.) immediately, even if they seem fine.
Want to keep your dog out of certain areas? Read how to keep dogs out of your garden.
When Mushrooms Are a Good Sign
Mushrooms growing in your garden also have a positive side. They show that your soil contains plenty of organic matter and active soil life. Fungi break down leaves, wood and roots into nutrients, and some partner with tree roots to help them take up water. If they do not bother you and no children or pets are at risk, you can simply let them be.
Healthy soil is also the basis of a productive vegetable garden; see vegetable gardening for beginners. For fall garden tasks, including leaves and mulch, see our checklist to winterize your garden.
Frequently Asked Questions
Why are mushrooms growing in my garden all of a sudden?
Mushrooms appear suddenly after a few days of rain or heavy watering. The fungus was already in the soil; wet weather simply triggers it to produce mushrooms.
Are mushrooms in my garden bad?
Usually not. Most mushrooms in the garden break down dead organic matter and do not harm plants. Remove them where children and pets play, because some are poisonous.
How do I get rid of mushrooms in my lawn?
Pick or mow them off, water less often but more deeply, aerate compacted areas, reduce thatch and remove buried wood. Fungicides are not effective against mushrooms in lawns.
Why are mushrooms growing in my mulch?
Wood mulch is food for fungi. When it stays moist, mushrooms, slime molds and other fungi appear. Rake the mulch to let it dry and keep it no thicker than 4 inches.
Are mushrooms in the lawn poisonous to dogs?
Some are. Remove mushrooms before your dog goes out, and call your veterinarian immediately if your dog eats one.
Do mushrooms mean my soil is healthy?
Often, yes. They show that your soil contains organic matter and active fungi, which recycle nutrients for plants.
Will mushrooms go away on their own?
Yes. Most mushrooms disappear within days when the weather turns dry, but they can return after the next rain.
What is the yellow foam in my mulch?
That is a slime mold, often called dog vomit fungus. It is harmless and dries up on its own; you can scoop it up and throw it away.
Can I compost mushrooms from the garden?
You can, but spores may spread to the compost and garden. If mushrooms bother you, put them in the trash instead.
Should I remove mushrooms growing in my garden?
Only if you want to or if children and pets play there. Mushrooms growing in my garden or yours do no harm to plants, but some are poisonous, so pick them off in play areas.
How do I get rid of mushrooms in mulch?
Rake or turn the mulch so it dries out, keep it no thicker than 4 inches and scoop up mushrooms and slime molds. Mushrooms in mulch disappear once conditions are drier.
Should I use a fungicide on garden mushrooms?
No. Fungicides do not reach the fungus deep in the soil and mushrooms rarely harm plants. Removing their food source works better.
Final Thoughts
Mushrooms growing in your garden are usually a sign of healthy, living soil, not a problem. They appear after rain, feed on organic matter and disappear when it dries out.
Pick them off where children and pets play, keep mulch and lawn from staying wet, and remove buried wood if mushrooms keep returning in the same spot. That is all you need to get rid of mushrooms or keep them under control.
Sources: University of Illinois Extension: managing fairy rings and mushrooms; University of Maryland Extension: mushrooms and slime molds in lawns; Iowa State University Extension: managing strange-looking fungi in landscape mulch; Penn State Extension: what is growing in my landscape mulch.
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