What Are The Black Mushrooms In My Lawn? (Solved & Explained!)

Understandably, if you have black mushrooms growing in your lawn, you’re a little irritated. You’ve taken good care of your yard, and the black mushrooms are ruining your perfectly preened grass.

But what are these black mushrooms? How can you remove black mushrooms from your lawn and prevent them from growing right back?

The black mushrooms in your lawn are most likely varieties of mushrooms called Scleroderma polyrhizum or Cyathus striatus.

You can identify the different mushrooms on their size and shape; large, vertical black mushrooms growing on the plants in your landscape are most likely the Scleroderma polyrhizum or another member of the Phallus species. 

Smaller black mushrooms that grow in flat, oyster-like patterns are the Cyathus striatus. These mushrooms are unlikely to cause you or your lawn any harm, but there are many ways of going about removing black mushrooms from your garden.

Causes Of Black Mushrooms in Garden

Regardless of their variety, the black mushrooms in your lawn are caused by the same few factors. Check out these factors, and hopefully, one or more of these reasons will explain the black mushrooms in your lawn.

Poor Draining

Mushrooms thrive when there is plenty of moisture, so if your lawn is damp, particularly in the areas where the mushrooms are growing, this might be why they were able to develop.

Consider whether you are watering your plants too frequently or whether a significant rainfall has allowed your lawn to get waterlogged. Of course – if it was due to rainfall, there are limits to how much you can do about this,  but be sure not to add to this problem by getting too enthusiastic with the hosepipe or watering can.

Shady Lawns

Along a similar vein, mushroom spores may be able to develop in your garden due to the amount of shade. Mushrooms do not like sunlight, so if you’ve got trees shading your lawn, or a garden fence that blocks the sunlight, this could also cause the black mushrooms.

If you have a shaded lawn, you mustn’t over-water your grass, as it will take a long while to evaporate, and the stagnant water provides perfect conditions for black mushrooms to develop.

Animal Waste

It’s unpleasant to think about, but the animal waste on your lawn may be helping black mushrooms to grow. If your yard is home to dogs, cats, or farm animals like chickens and goats, then the waste from these animals provides organic matter that creates ideal conditions for black mushrooms to grow.

Decaying Plant Matter

Decaying plant matter such as dead leaves, grass cuttings, dead branches, or old tree roots in your garden can also cause black mushrooms. Anything that is decaying is excellent food for mushrooms, so it might be worth having a thorough clean-up to prevent them from growing.

A lawn with a lot of thatch (the spongy top layer of the soil that is made up of dead grass and roots) will also provide the right conditions for mushrooms to grow. Dethatching your lawn will eliminate dead grass and other matter that could decay and become food for black mushrooms.

Dangers of Black Mushrooms In Your Lawn

As well as ruining the appearance of your grass, there are things to be wary of if you have black mushrooms growing on your lawn.

Though they may not be a poisonous variety, you should never consume black mushrooms in your lawn. They are a risk to have around if children use your garden or have pets that might try to nibble on the mushrooms out of curiosity.

Are the black mushrooms in your lawn dangerous? Probably not. But is it worth the risk? Not at all. There are over 100 species of toxic mushrooms, and many of these look entirely benign. For peace of mind, it is best to get rid of any black mushrooms in your lawn.

Removing Black Mushrooms From Lawn

Controlling black mushroom growth in your garden is problematic because it requires eliminating all of the mushroom spores. However, there are plenty of measures you can take to try to kill off the spores.


A quick solution to your black mushroom problem is to buy a fungicide to spray on your lawn or yard. However, be careful if using one of these on a lawn that pets and children use.

Dish soap

If you’re looking for an easy and natural solution to killing black mushrooms, then you can use dish soap.

Mix one or two tablespoons of any dish soap with up to a few liters of water. Poke holes in the soil around the mushrooms (for this, use a screwdriver or other sharp object).

Pour the solution over the mushrooms and into the holes in the lawn, and this will interrupt the growth of the fungi.

Repeat this process multiple times a week until you see a reduction in mushroom growth.

How To Prevent Black Mushrooms From Growing

Though you might struggle to eliminate all of the black mushroom spores in your garden, you can control the environment in your garden and make it hostile towards the mushroom spores.

Since black mushrooms require moisture to grow, allowing your lawn to dry out a little should prevent the mushrooms from thriving.

If you remove the mushrooms from your lawn, be careful not to put mushrooms in a compost pile, as their spores may be able to spread back to your grass from here.

Another way of taking action to prevent black mushrooms from regrowing in your lawn is to invest in a nitrogen-based fertilizer for your grass. Without any moisture or decaying matter to feed off of, mushrooms will turn to living on the decaying matter in your soil.

Adding nitrogen to the yard will increase the speed at which the organic matter decays. When it decays faster, the life cycle of the mushrooms will quickly end.

With this in mind, then, if you want to get rid of the black mushrooms in your lawn for good, a combination of simple lawn care and nitrogen-based fertilizer should tackle your black mushroom problem together.

The black mushrooms could be of various varieties, but the solutions remain the same.