How to Get Rid of Mushrooms Growing in Mulch?

Mushrooms are quick growers and they may appear seemingly overnight. Although they’re an indicator of healthy soil, they can be dangerous for children and pets, so it’s best to kill them as soon as they appear.

The most popular methods of killing mushrooms include vinegar, soapy water, and the use of fertilizers rich in nitrogen. However, the best way of keeping mushrooms at bay is prevention, which mostly includes keeping the yard clean and cleaning mulch when needed.

Read on to learn why mushrooms grow, whether they’re harmful or beneficial, whether they can pose a danger to anyone in your home, how to get rid of mushrooms growing in mulch, as well as preventing them from reappearing.

Why Mushrooms Grow in Mulch

Fungi are, in fact, completely natural in mulch. Mushrooms, among other fungi, can grow more or less anywhere. Their occurrence is the most natural thing when it comes to mulch decomposition.

Bacteria and fungi are very much involved with organism decomposition. Mushrooms break down woody tissue and in return, they grow. This most often happens during the wetter part of the season, particularly after rains.

Mushrooms grow best in humid environments. The reason for this is the speed of decay, as wet conditions speed up the decomposition of organic materials.

So, a wet environment with plenty of organic waste is the ideal place for mushroom growth.

Are Mushrooms Growing in Mulch Harmful?

Mushrooms that grow in mulch are not harmful to plants or to your lawn, but they can pose a danger. Since some mushrooms are toxic and capable of causing minor health issues (at best) or even killing animals (at worst), they can be dangerous for pets and children.

To make sure nobody gets hurt, it’s best to remove them from the mulch as soon as possible. However, to keep them from reappearing, it’s best to apply mushroom prevention methods.

Are They Toxic to Dogs or Other Pets?

Depending on the specific species of mushroom, yes – mushrooms can definitely be toxic to pets. There are probably a lot of plants in the garden that are toxic to pets, but that depends on the amount they eat.

One thing is for certain – dogs are very curious animals and it’s almost guaranteed that they’ll take a bite.

Can Mushrooms Be Beneficial?

Although health should always be the primary concern, it’s true that mushrooms (and fungal systems in general) can be beneficial for the garden.

Firstly, mushrooms speed up the decomposition process. Rotting fruit, plants, and all other organic waste are decomposed much more quickly when there’s fungus around.

Mushrooms release enzymes that speed up the process of decomposition, essentially eating the waste. Fungi only appear when there’s something to decompose as that’s the way they feed.

The second way mushrooms can be useful is by protecting plant roots. The hyphae of fungi (which is the equivalent of the root in plants) will sometimes intertwine with plant roots.

When this happens, they achieve a sort of symbiosis, with the mushroom hyphae suppressing soil-borne pathogens and protecting the plants from diseases.

Mushrooms Are Indicators of Healthy Soil

Mushrooms can be described as the reproductive organs of fungi, and the occurrence of mushrooms guarantees that the soil is healthy.

Fungi won’t appear in unhealthy soil. When it appears, fungi will intertwine with plant roots (as is explained in the aforementioned symbiosis). Once this relationship is established, the fungi will release compounds that improve soil quality.

The structure of the soil improves, as well as soil porosity.

Despite all this, mushrooms should always be taken out of the soil if there are children or pets around, as the risk of intoxication is too great, despite the potential benefits.

How to Kill Mushrooms Growing in Mulch

Mushrooms Growing in Mulch

Here are the most effective methods of killing mushrooms in mulch. Experts insist, however, that no method of killing mushrooms is permanent. These organisms grow only for a short while and they’ll probably die quickly on their own.

The best way to get mushrooms out of your garden isn’t to kill them, but to prevent them from ever developing.

1. Use Baking Soda

While baking soda will slow down the growth of mushrooms, it will not stop it completely. Mushrooms grow best in acidic soil, and adding a mixture of baking soda and water will make them more alkaline.

This will slow down the rate of mushroom growth. However, the effects of baking soda on the soil will wear off soon, and soil pH will return to its normal acidic nature.

The most effective way of applying baking soda to mushrooms is by ripping the mushrooms out of the ground and only applying the solution then. This will prevent the mushrooms from growing, but only temporarily.

To apply baking soda:

  1. Mix 2 tablespoons of baking soda with a gallon of water
  2. Spray the solution over the mushrooms and the soil

2. Fungicide for Mushrooms

Just like baking soda, fungicides don’t actually kill mushrooms, they only stop them from growing any further. Because of this, fungicides are a good solution for prevention, but they’re not that good for killing mushrooms that grow in the mulch.

Why is this? Because commercial fungicides that can be purchased at your local gardening store aren’t made for mushrooms, but rather, they are intended for minor fungal growth such as mold and mildew – which are much easier to kill than mushrooms.

Applying fungicides to areas that are prone to mushroom growth, is also a viable preventative option.

3. Household Vinegar

Just like baking soda, vinegar seems to be a very common household solution for many problems. Unlike the previous two options, though, vinegar will actually kill the mushrooms.

White vinegar contains acetic acid, which is fine for humans, but it’s lethal for mushrooms.

To increase your chances of success and prevent mushrooms from growing again in a particular spot, I recommend combining white vinegar with a shop-bought fungicide.

  • Mix vinegar (and fungicide) with water in a 1:4 ratio
  • Spray it on the mushrooms

4. Soapy Water

Soap water can also kill mushrooms, but the effects of this method are still up for debate. Although soapy water can kill mushrooms, little is known about how long it will last.

It’s generally easy to kill mushrooms (you can literally just rip them out of the ground), but they’re difficult to eradicate completely as they keep regrowing.

  • Mix 3 tablespoons of dish soap with 2 gallons of water
  • Dig small holes around the mushrooms
  • Pour the solution into the holes

5. Nitrogen-rich Fertilizers

All types of fungus feed on decomposing matter, and applying nitrogen to the soil will slow down the rate of decomposition. Since there’s less decomposing matter, the mushrooms have less to feed on and their growth rate drops significantly.

After this, simply ripping them out or using any of the methods mentioned above should be enough to kill them.

How to Prevent Mushrooms in Mulch

Mushrooms in Mulch

Before learning how to get rid of mushrooms growing in mulch, remember that the most effective way of keeping them at bay is by keeping your garden tidy. Mushrooms need specific conditions to grow, and if you keep your garden tidy, mushrooms most likely won’t grow.

1. Keep Your Yard Clean

A lot of organic waste can contain spores, which are the means of reproduction of fungi. A regularly cleaned yard has less organic waste, which means fewer spores, which means fewer mushrooms, and other fungi.

Dead plants, fruits, and all other decomposing matter need to be thrown away.

When it comes to animal droppings, they can raise the acidity of the soil, which will only insight mushroom growth since they prefer acidic soil.

2. Rake Your Mulch Regularly

Raking the mulch is very similar to lawn aeration – it allows for more air to get in, thus minimizing the level of humidity. Since mushrooms prefer highly humid environments, keeping the mulch well-aerated is crucial to minimize mushroom growth.

Mushrooms aren’t the only form of fungus developing beneath the mulch – most of them are not easy to detect until it’s already too late.

Another great way of preventing mulch development is soil aeration. This is something that should be done at least twice a year either way. By aerating soil, you allow more air to get to the soil and lower the levels of humidity.

3. Avoid Overwatering

Overwatering any plant is dangerous because it can lead to root rot. When there’s too much water in the soil, the levels of moisture rise to such a degree that underground fungus develops easily.

If you overwater your mulch, among other things, it will retain water for a very long time. Wood chips are not as well draining as soil, and overwatered mulch will retain water for longer than soil, making it an ideal environment for mushroom growth.

In a combination with soil with bad drainage, overwatering mulch is almost guaranteed to lead to fungus growth.

4. Add a New Layer of Mulch

Since it takes years for mulch to decompose, adding a new layer on top of the old mulch will freshen your mulch. It will also slow down the growth of mushrooms (or completely prevent it if you’re lucky), since the new mulch isn’t a suitable environment for mushrooms to grow in.

5. Replace the Mulch

The best way to keep mushrooms from growing is by replacing the old mulch with new mulch. This isn’t necessary if the mulch hasn’t gotten damp and you’ve applied fungicides that prevent the mushrooms from growing.

However, mulch usually becomes damp and the level of moisture becomes high after a few years – even if it’s regularly raked and the yard is kept clean.

In this state, mulch is the ideal environment for the development of mushrooms, and the only way to stop them from growing is by replacing the old mulch.

6. Consider Using Compost Instead of Mulch

Specific varieties of compost can be found in garden stores, not to mention that some garden stores will make compost according to their wishes. Highly-alkaline compost can be a very good solution for mushrooms.

Since they need highly acidic soil to thrive, alkaline compost will prevent them from growing as it makes an unfavorable environment.

7. Remove Tree Stumps and Roots

Tree stumps are an ideal breeding ground for mushrooms and they’ll easily grow on them. In fact, you can see that in the wild – forest mushrooms almost always grow on tree stumps and roots or on the ground right above the roots.

Once they’re established on the stump, mushrooms will spread very easily to anything nearby – including mulch.

FAQs How to Get Rid of Mushrooms in Mulch

Final Thoughts on Mushrooms Growing in Mulch

Despite their possible benefits, mushrooms can pose a danger to children and pets, so it’s best to remove them from the garden immediately. 

Most methods of mushroom removal aren’t long-lasting, and the most effective way of keeping them out of the garden is by preventing them from growing.

Keeping the garden clean, and aerated, and keeping the mulch fresh will keep the mushrooms at bay for a long time.