Dealing with mushrooms and toadstools in your lawn

Mushrooms and toadstools are a common problem in Australian lawns, and can cause endless frustrations for lawn-proud homeowners.

What exactly are mushrooms and toadstools?

Mushrooms and toadstools are the reproductive part of a type of fungi that lives in the soil. For much of the time, the fungal structures remain hidden underground, breaking down organic material in your lawn. But when the time is right, mushrooms and toadstools burst forth from the underground structures and appear in your lawn.

How do mushrooms and toadstools spread through my lawn?

Mushrooms and toadstools spread spores through the air, allowing them to propagate widely.

Causes of mushrooms and toadstools in your lawn

Fungi such as mushrooms and toadstools thrive in the following conditions:

• Moist, damp environments. Mushrooms thrive in moist environments, and often appear after rain or in areas with poor drainage.
• Shady or protected environments with poor air circulation.Mushrooms love shade and areas that are protected from good air flow, such as the damp, boggy corner of your garden.
• Environments rich in organic matter.Grass clippings, leaves, thatch, old mulch, compost, wood, and animal waste often abound in the average lawn, providing an ideal environment for mushroom growth.
• Warm, humid weather conditions. This type of weather provides just the right conditions for mushroom and toadstool growth.

Should you leave mushrooms and toadstools growing in your lawn?

It might surprise you to know that mushrooms and toadstools aren’t actually harmful to your lawn at all. In fact, they can be quite beneficial for your lawn. It’s important to distinguish between fungi such as mushrooms and toadstools and fungal lawn diseases, however. Fungal lawn diseases can damage the grass in your lawn; whereas mushrooms and toadstools assist with the breakdown of organic matter in your lawn, thus making the soil richer and full of nutrients. As well, the extensive root structure of mushrooms can help the soil retain water – good news in Australia’s often-dry conditions.

Mushrooms and toadstools are actually a good sign that your lawn is healthy and thriving. They are part of the growing environment and an integral part of the natural ecosystem.

However, while they won’t damage your grass, many varieties of mushrooms and toadstools that grow in your lawn are poisonous. Even if they’re not the poisonous type, humans and animals shouldn’t eat them. This can be a problem if you have small children who like to get into everything, or curious pets.

So, if unsightly mushrooms are ruining the smoothness of your lawn, or you have pets or children, you probably want to get rid of mushrooms and toadstools completely.

Why is it hard to eliminate mushrooms and toadstools from your lawn?

It’s quite difficult to completely eradicate mushrooms and toadstools from your lawn. This is due to the way they grow and spread. The underground part of the fungus can remain dormant in your soil for years, before coming to life when the conditions are right. The surface part of the fungus that you see – the mushroom or toadstool head – is only a small part of the fungus, and will usually only last for a few days. Think of the mushroom like a lemon on a tree – you can pick the lemon, but that doesn’t remove the tree at all. The underground structure of the fungus can often be so large that you’d never be able to find all of it and dig it out.

So how can you reduce the appearance of mushrooms and toadstools in your lawn?

While you may not be able to eradicate the fungal structures completely, you can make your lawn an unattractive place for fungi to grow. Here are a few strategies you can try to correct the problems in your lawn leading to mushroom and toadstool growth.

Decrease shade in problem areas

If you regularly find mushrooms growing in certain areas, check to see if they are overly shady. Sunshine helps keep mushrooms and toadstools in check, as they much prefer to grow in the shade. Trim back trees or shrubs that are overhanging the lawn, or thin out the branches to allow more sunlight through. This will also allow more air to circulate in problem areas.

Aerate your soil and improve drainage

If your lawn often has standing water or remains damp after rainy spells, your soil might be compacted. Compacted soil can cause moisture build-up in your lawn, leading to the damp, sodden conditions that mushrooms love. Aerating your lawn will improve drainage problems, allow more oxygen to get to the roots of the grass and decrease the moisture that mushrooms love. Click here to find out the best way to aerate your soil and prevent compaction.

Don’t overwater

While new lawns need plenty of water to help them get established, older lawns don’t need to become sodden and drenched regularly. Yes, they need water, but not to an excessive degree. Excessive watering can encourage mushroom and toadstool growth, particularly if you water late in the evening and allow the water to sit on the grass all night. Water during the morning to allow the water to absorb and dissipate. For more information on the do’s and don’ts of watering your lawn, see this article.

Don’t leave grass clippings on the lawn

While this is beneficial in certain circumstances (see this post on grass clippings here), if you’re having problems with mushrooms you may want to limit this practice for a while.

Remove thatch build-up

When excessive thatch builds up in your lawn, it can provide a good food source for toadstools and mushrooms as it decays. If it’s more than half an inch thick, it’s time for a good de-thatching. Click here to find out how to remove thatch when spring cleaning your lawn.

Replace old mulch

A lot of decaying organic matter in and around your lawn will encourage mushrooms to grow.

Reduce the amount of fertiliser you apply to the lawn

While fertiliser is necessary for a healthy lawn, you may be applying too much. Follow the instructions on the packet and apply only as much as recommended. More is not necessarily better and may merely be providing extra food for mushrooms.

Clean up after your pet

In a similar manner, animal waste left on the lawn can also bring out mushrooms and toadstools. Clean up after your pet where possible to reduce the amount of food available for fungal growth.

Remove tree stumps and rotting wood

These are just a rich source of food for mushrooms. Even if you have removed trees, the rotting roots left underground can encourage mushroom growth. Remove everything you can, and rake and aerate the area to improve drainage.

Remove buried debris

Often toadstools are feeding off debris that is buried underneath your lawn, not the lawn itself. To find out, dig under a clump of mushrooms and look for any buried plant debris or organic matter. If you find anything, simply dig it out and relace the turf. The mushrooms shouldn’t last long.

Remove by hand

Wear gardening gloves and pick or brush off the mushrooms and toadstools. While this won’t prevent them coming back, it will prevent the spores from spreading further. You can also mow them off – just make sure you use the collector on your lawnmower, so they don’t remain on the grass.

Use fungicide

If all else fails, you could try using a fungicide to deal with unwanted mushrooms and toadstools. However, if you don’t deal with the issues causing them to appear in the first place, there’s a very good chance the mushrooms will just grow back. In most cases, fungicide will have limited effectiveness on mushrooms and toadstools, so try the other strategies first.

With a little bit of effort, you’ll soon have a lawn where mushrooms and toadstools are afraid to rear their heads!