Orange Fungus in Mulch - Annoying Slime MoldThe orange fungus in mulch is usually an uninvited and unwanted visitor that attacks many home gardens. It might knock on your door too — that is, if it hasn’t already.

Getting more information on how to identify and deal with this fungus is of paramount importance. This article delves deeper into the nitty-gritty of what you need to know about the orange fungus in mulch.

How To Get Rid of Orange Fungus in Mulch?

Washing off the fungus, manually removing it, or applying heat are just some of the methods you can use to get rid of this annoying problem. The orange fungus in mulch is harmless and nontoxic, even if you were to leave it on the soil of your plants. However, some people just can’t stand the sight of this orange mold on soil. If you are one of these people, this section will give you tips on how to deal with the unsightly mold.

– Wash Off the Fungus

You can wash off the orange fungus using a strong stream of water. Using a garden hose is ideal for this purpose.

– Manually Remove the Fungus

You can even manually remove the orange fungus by breaking down the mass of the slime mold into smaller pieces using a shovel. You can then rake it and remove it from the rest of the mulch. Take note that the orange mold will hold on tight to substrates, making it difficult to remove.

We also recommend that you dig out the affected portion and dispose of it. This reduces the rate at which the fungus spreads to other parts of the mulch.

– Spray the Fungus

Mix vinegar and water prior to putting the solution in a spray bottle. Spray the fungus with this solution. Do this consistently to ensure that the fungus is destroyed.

Vinegar contains acetic acid, which is able to completely destroy the fungus. The only downside with this method is that the acetic acid in vinegar can further damage plants that have been affected and weakened by fungal infections.

– The Cornmeal Method

Combine cornmeal and water to make a thick paste. Spread this paste on the area that is mostly affected by the mold. When you apply the cornmeal mixture, make sure to also apply it a few feet around the specific area that has been infected.

To enhance better strength of cornmeal as an antifungal agent, apply 20 pounds for every 1,000 square feet of soil. The visible results of applying the cornmeal are seen within three weeks after the day of adding the cornmeal.

– Apply Heat

Another way to deal with the orange fungus is through heating the substrates, be it soil or mulch. Heat the substrate to a temperature of about 104 F. You can use an oven or hot plate for this. This temperature is high enough to destroy the orange fungus from your mulch or soil since it can’t survive under such high heat.

You can also remove the mulch or soil that is affected by the fungus and place it on a sunny spot. Direct sunlight will also help to destroy the orange fungus.

– Replace the Substrate

It is difficult to completely get rid of the orange mold once it has attacked your garden. The reason for this is that the spores will keep spreading and reproducing more of the fungus.

In the case of an orange fungus growing in mulch, the best way is to remove the old mulch and replace it with a new one. The same thing applies to the orange fungus on soil. Simply get rid of the potting mix and prepare another one that is disinfected.

When you discover the orange fungus in flower beds that are covered in mulch, assess the situation before you promptly replace the mulch. If the problem is minor, regularly separate the mulch, throw away some of it and retain the lower layer. Add a new mulch on top of the existing one to help you control the fungus.

The Orange Fungus in Mulch: What Is It?

The orange fungus in mulch is scientifically known as Mutinus elegans, and it is usually characterized by an unpleasant smell and a phallic shape. Most of the time, the orange fungus in mulch appears orange in color, but it can sometimes be yellow. This substance is also referred to as slime mold, dog vomit fungus or stinkhorn. 

There has been a lot of research as scientists tried to figure out if the orange fungus in mulch is a pure fungus. Available information suggests that the orange fungus in mulch is not really a fungus as its name suggests, nor is it purely mold.

This is why this substance is now scientifically classified a`s a protist. Although protists are not animals, plants or fungi, they act a lot like them, which is why it is believed that they were involved in the evolution of plants, fungi and animals.

The orange fungus in mulch can grow to a height of approximately seven inches. Another interesting fact about the slime mold is that it thinks, though it does not have a brain. This substance also moves as it releases spores. The bad odor of the orange fungus in mulch causes it to attract insects such as flies, which are then trapped by the slime the moment they come into contact with it.

– Variations

Sometimes, the orange fungus that grows in your mulch could be Physarum polycephalum. This is also a slime mold and it feeds off vegetation. The Physarum polycephalum can appear as slimy clumps on your mulch. For identification purposes, this mold is similar to a scrambled egg in its appearance.

– The Orange Fungus on Ground

The orange peel fungus, which is scientifically known as the Aleuria aurantia, grows directly on the ground because they are stemless. This is also referred to as the orange fairy cup fungus due to its cup-like body and bright orange color, which explains why this fungus is referred to as the orange fungus on ground. When you look at this fungus, you might think that they are orange peels that have been discarded.

The orange peel fungus is found in clusters in open areas particularly near dead trees, woodland trails and roadways. Take note that the orange peel fungus is not poisonous so it can be consumed, although it is relatively tasteless.

The orange peel fungus does not produce toxins, but its appearance is very similar to that of some Otidea fungi that are known for producing toxins that are dangerous to human health. Because of this, it is better not to eat it without proper identification by a professional.


Conducive Conditions for the Orange Fungus in Mulch

The orange fungus in mulch promotes the decomposition of plant material as it feeds on the bacteria that are involved in breaking down organic matter. Therefore, the presence of dead and decomposing plant material in your garden attracts the growth of this slime mold. The orange fungus in mulch also appears when the temperatures are warm and humidity is high.

We recommend that you avoid overwatering the plants in your garden at all costs. The orange mold prefers very wet conditions. If you are growing your plants in pots, put them indoors when it’s raining to avoid unintentionally creating waterlogged conditions that favor the growth of this fungus. Sunlight and ample aeration negatively affect the survival of the orange fungus.


The orange fungus in mulch reproduces through spores. Millions of spores are released into the air and these spores, which look like eggs, then move from one point to another through contact or air dispersal. The wind aids their dispersal by air.

The spores, which are whitish in color, will grow into orange or yellow substances that are covered in slime.  The orange fungus in mulch may appear as an orange fungus on houseplant soil, flower beds, mulch, white chip piles or any other soil. The slime mold will eventually die and turn into a spot that is white and powdery.


Is orange mulch fungus harmful to plants?

Orange mulch fungus can harm plants, causing decay and inhibiting growth. It’s important to address and treat the fungus promptly.

Can a homemade fungicide be used against orange mulch in fungus?

Yes, homemade fungicides can be effective against orange mulch fungus. Some commonly used ingredients for homemade fungicides include baking soda, neem oil, and vinegar.

What is the best mulch to prevent orange mulch fungus?

To prevent orange mulch fungus, it’s recommended to use mulch that is less prone to fungal growth. Organic mulches like pine needles, cedar bark, or hardwood chips are generally less favorable for fungus compared to mulches like wood chips or straw. Additionally, maintaining proper moisture levels, ensuring good air circulation, and regularly inspecting and removing any decaying organic matter can help prevent fungal growth in mulch.


The orange fungus on groundYou now have a good idea of how to differentiate the types of orange fungus that exist in your soil. In addition, this article extensively discussed the various strategies that you can employ in dealing with the orange fungus in mulch.

  • The orange fungus in mulch usually appears orange, though it can also have a yellow color.
  • Scientifically, the orange fungus in mulch is usually Mutinus elegans or Physarum polycephalum.
  • Another fungus that grows directly on the ground is the orange peel fungus, whose scientific name is Aleuria aurantia.
  • The orange fungus in mulch prefers warm and wet conditions.
  • This fungus reproduces through spores that are dispersed by air currents or through contact.
  • It is difficult to prevent the growth of the orange fungus in mulch, but not overwatering your plants will help.
  • To deal with the fungus on your mulch, employ these strategies: replacing the mulch, manually removing the fungus, spraying with diluted vinegar, treating with cornmeal, or heating the mulch at a temperature of 104 F.

There is no need for you to worry when you see orange fungus growing on your mulch. Simply apply the tips and tricks that are provided in this article and gain the expertise to deal with that annoying orange fungus!

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