Mushrooms in the Lawn: The Causes & What to Do About Them

Have you woken up and stepped outside to notice mushrooms have suddenly appeared in your lawn?

It’s common for lawn owners to freak out when they see mushrooms or toadstools in the lawn but they aren’t necessarily a bad thing. In 99% of cases, it’s actually a sign of a healthy lawn.

Sometimes though, it can be a problem.

Also, if you have kids and/or pets you’ll need to remove them. As we all know, eating the wrong kind of mushrooms can have serious consequences.

What Are Mushrooms?

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In all lawns, there are hundreds, thousands of fungi.

They’re the most active micro-organism in turf. They help degrade lawn thatch and feed on dead organic matter such as fallen leaves, old grass cuttings, dead grass roots, bits of decaying bark or dying tree roots. This, in turn, provides the soil with nutrients which aids grass growth.

Most fungi can’t be seen, it exists as numerous fine threads or filaments called Hyphae. Together these filaments make up what is called ‘Mycelium‘ which is practically invisible to the naked eye.

Although you won’t see most fungi, a few species produce mushrooms or toadstools.

These mushrooms are referred to as ‘Fruit’. They’re the reproductive structure of the fungi and they come in all different shapes and sizes, not just the classic mushroom shape we’re all familiar with.

If you look at the underside of a mushroom you’ll see lots of gills. These gills contain millions of spores that get carried through the air and germinate when they land in favourable conditions.

Good Mushrooms vs. Bad Mushrooms

Most of the time mushrooms in your lawn is a sign that it is in good health with nutrient-rich soil.

Yes, they might be an eyesore but they’re easy enough to get rid of (more on that later!)

Sometimes though, they can be a sign of trouble.

If you have mushrooms or toadstools that grow in a circle in your lawn you could be looking at a fungal infection commonly called ‘Fairy Rings‘.

What Causes Mushrooms to Grow in Your Lawn?

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Like I said, many people freak out when they see mushrooms popping up in their lawn so it’s worth repeating;

In 99% of cases, mushrooms in your lawn is a sign of health.

Mushrooms can’t grow in soil that is devoid of nutrients so the fact that you’ve got mushrooms in your lawn tells you that your soil is fertile.

As well your soil being fertile, there are a few other reasons why mushrooms might grow in your lawn;

Conditions Are Cool, Damp and Shady

Mushrooms grow best in cool, damp and shady conditions.

If your lawn is covered by shade and the weather is cool after a prolonged period of rain, you might experience a sudden surge of mushrooms.

A Build-Up of Excessive Lawn Thatch

Sometimes mushrooms grow as they feed on the decaying organic material that is in the thatch layer.

If you see clusters of small mushrooms in your lawn, have a look for excessive thatch. If there’s more than half an inch, scarify your lawn.

Drainage Issues

If your lawn has a drainage issue then moisture will sit on the surface.

Check your lawn for soil compaction and spike it in the spring with either a garden fork, a rolling spiker or aeration sandals.

Use a hollow-tine aerator to remove cores of turf from your lawn in the autumn.

Doing this will improve drainage and allow water to penetrate deeper into the soil so it doesn’t sit on the surface. It’ll also improve airflow through the soil which helps keep it a bit dryer.

Decaying Tree Stumps or Wood Under the Surface of Your Lawn

If you see mushrooms popping up in a certain area of your lawn there might be some decaying debris in that area.

In which case you can either;

1. Leave it – once the fungi have broken it down you’ll no longer see mushrooms, or
2. Remove it – by taking the turf up, removing the decaying material and replacing the turf.

You Have Recently Re-Turfed Your Lawn

Mushrooms are very common in freshly laid turf.

Harvesting, transporting and re-laying turf can stimulate sporing and the growth of new mushrooms or toadstools. Especially when you water in your new lawn.

This is perfectly normal and nothing to worry about. If your lawn has mushrooms in it after laying new turf, don’t freak out and leave negative reviews for the turf supplier!

This happens all the time.

How to Remove Mushrooms From Your Lawn

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Mushrooms won’t do any harm to your lawn but they can be an eyesore. They can also make you, your kids or your pets very poorly if you eat the wrong ones.

They generally only stick around for a few days and they disappear when the weather dries out. But, it is best to remove them to prevent any accidents.

Because mushrooms are just the fruiting bodies of fungi, picking them out of your lawn won’t kill the underground Mycelium which they grow from.

It will, however, reduce the chances of them spreading their spores to new areas.

To remove mushrooms you can either;

• Brush them
• Pick them, or
• Mow them

If you brush or pick them, make sure you wear gloves as a precaution.

Because the Mycelium will still exist, chances are that mushrooms will come back when conditions are favourable.

To completely stop mushrooms growing you must kill the Mycelium from which they grow which is;

1. Nearly impossible, and
2. Not recommended because of the benefits it brings to the health of your lawn

If Your Lawn is Taken Over By Mushrooms, Consider Replacing it

A few mushrooms in your lawn is common and a good thing but if mushrooms have completely taken over, consider replacing it.

A lawn that is packed with mushrooms is horrible to look at and it could be dangerous for kids and pets to use.

Removing the turf could uncover decaying organic matter that should be removed to prevent mushrooms from growing back. It might also be wise to replace the topsoil as the amount of Mycelium will be extensive.

How to Prevent Mushrooms Growing in Your Lawn

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Completely preventing mushrooms from growing in your lawn is almost impossible. Given the right conditions, they can pop up no matter what you do.

That said, there are things you can do to reduce the chances of them appearing. We already touched on a couple of them earlier in this article but they’re worth repeating;

Scarify Your Lawn to Reduce Thatch

Mushrooms can form as they break down organic material in your lawns thatch layer.

By scarifying you;

1. Reduce the amount of organic material that fungi can feed on in the thatch layer, and
2. Allow more water to penetrate into the soil so it’s not sat on the surface or in the thatch layer.

This reduces the chances of mushrooms from growing.

It also reduces the chances of other fungal diseases like Red Thread, Pink Patch and Snow Mould or Fusarium or Ophiobolus Patch from becoming an issue.

Read: How to Choose the Best Scarifier For Your Lawn

Aerate Your Lawn

If the soil in your lawn is compacted then water will sit on the surface. When combined with cool, shady conditions mushrooms grow rapidly.

Aerate your lawn by spiking it to a depth of 2-3 inches in Spring and Autumn with a garden fork, rolling aerator or aeration sandals.

Also, hollow-tine every 2-3 years to remove cores of turf from your lawn. This causes the soil particles to relax and separate from each other.

Aerating your lawn improves drainage so water can penetrate the soil instead of lying on the surface. It also improves airflow through the soil which keeps it dryer.

Pick Up Leaves and Animal Waste Regularly

Leaves, animal waste and other organic debris is perfect fungi food and will decompose on your lawn if you leave there. This is an environment in which mushrooms grow well.

If your pets use the lawn as their toilet pick it up as soon as you can. Remove leaves and other material at least once a week especially in the autumn and winter.

If Possible Reduce Shaded Areas

One of the key ingredients for mushroom growth is shade.

If mushrooms grow in the shaded areas of your lawn, try pruning the surrounding trees to allow more sunlight onto your lawn. Also, prune any hedges as this will improve airflow over the garden.

If buildings cast shade over your lawn, there might not be a lot you can do. If fences cast it, try replacing solid fence panels with slotted ones. This will let more light through.

Wrapping Up

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If mushrooms pop up in your lawn, don’t panic.

In nearly all cases they won’t harm your lawn, they are quietly going about their business helping to decompose dead, organic matter and putting nutrients back into the soil. Nutrients that your grass can use to create food and grow.

Still, it’s a good idea to remove them to avoid kids and pets being poisoned.