4 Common Causes of Mushrooms in a Lawn

Have you ever gone to sleep and woken up to a brand new patch of mushrooms growing on your lawn? You might have removed them earlier, only to find them growing back by the next day. To effectively remove the mushrooms from your lawn, you should first understand what causes them to grow.

The most common cause of mushrooms growing is excess moisture in the ground. This could be caused by rains, overwatering, poor drainage, etc. Other causes of growing mushrooms include organic material in the soil and lack of sunlight.

In the rest of this article, I’ll talk about the most common causes of mushrooms growing on your lawn.

1. Excess Water in the Soil

Mushrooms are merely the above-ground reproductive parts of fungi. Fungi grow and spread below ground by absorbing nutrients from the soil and recycling them into substances that enrich the soil. 

When the conditions are ideal, these fungi grow mushrooms, which release airborne spores that land in other areas and grow into fungi. In simple terms, mushrooms are to fungi, what flowers and fruits are to trees.

The biggest cause of the sudden growth of mushrooms is excess moisture in the soil. Damp, dark conditions are essential to the growth of mushrooms, so any increase in water provides the ideal conditions for them to grow. The excess moisture can be caused by improper lawn maintenance, soil conditions, and weather conditions.

Let’s take a look at some of the most common causes of excess water in the soil.

Heavy Rains Produce Mushrooms

Naturally, heavy rains could cause a build-up of water in the ground. This build-up produces the ideal conditions needed for mushrooms to grow. So don’t be surprised if you suddenly have mushrooms on your lawn overnight after heavy rains.

In fact, mushrooms often produce more rain by releasing spores that support condensation. So it creates a cycle of heavy rains leading to mushrooms, which in turn lead to heavy rains.

Poor Drainage in the Soil Leads to Water Build-Up

You may have had a relatively dry spell but still have mushrooms sprouting up on your lawn. If it hasn’t rained, then what’s causing the water build-up?

The answer may lie in the soil drainage. Soil drainage refers to the process of water moving through and out of the soil because of gravity. If your soil is very compact and packed tightly, it might result in poor drainage. This means the water remains in the ground for a long time instead of draining away naturally.

The build-up of water in your soil could adversely affect your plants. Unlike mushrooms, plants require some air to grow. In poorly draining soil, water fills up all available space, leaving no place for air. This essentially drowns your plant roots since they can’t access the air they need to grow. It could also lead to disease or root rot.

Overwatering Your Plants Can Cause Water Build-Up

A common cause of mushrooms is garden owners watering their plants too much. Some plants require more water, while some can manage less. However, watering your plants too much could create the ideal conditions for mushrooms to grow – damp, dark, and full of nutrients from organic material.

Humidity Can Cause Mushrooms to Grow

The last cause of moisture build-up in your soil could be humidity. If you live in a humid climate, chances are that your soil already has quite a bit of moisture. There isn’t any way to ‘fix’ this, but you could make small adjustments.

In very humid climates, you might want to adjust your watering schedule to account for the moisture in the air. Mushrooms thrive in damp conditions, so you’ll need to limit the amount of water in the soil to prevent them from growing.

2. Lack of Sunlight or Excess Shade

The second reason for mushrooms growing is a dark environment. As mentioned before, mushrooms prefer a damp and dark environment to grow. So, if your lawn has a lot of shade or poor sunlight, you could end up dealing with a sudden mushroom infestation.

Technically, sunlight does not harm mushrooms, although they grow faster in the absence of sunlight. In fact, some research suggests that mushrooms produce higher amounts of Vitamin D when they have as little as 15-20 minutes of exposure to sunlight. 

However, they do not require sunlight to grow since mushrooms don’t have chlorophyll, which breaks down solar energy to grow. Mushrooms grow on organic material in the soil or from host plants.

If you have a problem with mushroom growth, try letting more sunlight hit your lawn, and trim away some of the overgrown trees or shrubs to let more sunlight through. This may not fully eliminate your mushrooms, but it should reduce the number of mushrooms growing on your lawn.

3. High Amount of Nutrients in the Soil

Some garden owners actually believe that mushrooms are a good sign. They might be annoying or, in some cases, dangerous, but they also indicate something very important about your garden soil.

Mushrooms grow extremely well in nutrient-rich soil. The higher the nutrient content of your soil, the more likely you are to have mushrooms growing.

Some of the main nutrients that mushrooms require to grow are as follows.

  • Carbon (C)
  • Nitrogen (N)
  • Magnesium (Mg)
  • Phosphorus (P)
  • Potassium (K)

The elements mentioned above are considered macronutrients for mushrooms. This means that these elements are required in large amounts for mushrooms to grow. Of the ones mentioned above, carbon and nitrogen are the most important macronutrients.

Some other nutrients that mushrooms thrive on are iron, zinc, and copper. These aren’t as essential to mushroom growth as the macronutrients, but they help in various other functions.

So if you’ve got a high growth of mushrooms without water build-up, it could just be because your soil has a high concentration of nutrients.

In this case, you might not want to do anything to ruin the nutrient content of the soil, especially if you’re using the same soil to grow plants in. So the best thing to do would be to just knock over the mushrooms and clear them away.

4. High Amounts of Organic Material

The last and most important cause of high mushroom growth is organic material. Organic material refers to any carbon-based compounds from animal and plant waste.

Remember how I mentioned earlier that carbon is one of the most important macronutrients? Well, here is the main carbon source for mushrooms and other fungi.

Mushrooms grow either in the ground because of fertilizer or dead plant matter or as parasites on plants. They synthesize their food by breaking down organic material.

There are two main sources of organic material: plant matter and animal matter.

Plant Matter

Plant matter refers to:

  • wood
  • leaves
  • dead plants 
  • and trees, roots, etc. 

These are all parts of a plant that act as a source of nutrients for mushrooms. Dead bark, in particular, provides a perfect environment for mushrooms to grow. That’s why you’ll often notice mushrooms growing on logs or fallen branches.

If you have a mushroom infestation, check your lawn to make sure that you don’t have dead plants cluttering it up. These provide the ideal conditions for mushroom growth, so you’ll need to clear them before the mushrooms grow in the soil.

If the mushrooms are growing only on the dead plants, then getting rid of them is a simple matter of throwing them away.

Animal Matter

Animal matter refers to animal waste, usually in the form of feces and dead bodies of insects or animals. Feces, in particular, contains almost all of the macronutrients needed for mushroom growth.

I mentioned earlier that organic material is a mushroom’s main carbon source, one of the most important macronutrients. Animal feces contain high amounts of nitrogen, phosphorus, and potassium, which make up some of the other macronutrients needed for mushroom growth.

So if you’re using fertilizer or compost, it’s highly likely that those nutrients are fueling the mushroom growth in your lawn. You could also be seeing mushrooms if you have pets that are let out onto the lawn to defecate.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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