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Brown Fungus on Soil? Here’s what you should know

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Are you wondering why your soil garden or potted plant is getting enveloped with brown fungus?

What does brown fungus look like? Can it spread from plant to plant or animal to animal?

Fungus grows on plants and animals. Some fungi cause disease. Others are beneficial. Brown fungus is a common type of fungal infection found on leaves, fruits, flowers, and stems. 

However, it can also be found on soil and can exist in larger, more predominant forms than those found on the plant.

Most often, it causes little harm to its host.

It’s important to distinguish between harmful and harmless types of fungi.

Brown fungus, also known as brown-rot fungus, is genetically called dry rot. When the soil remains extremely moist or soggy due to overwatering, it may give accommodation to the growth of brown fungus if any spores are in the soil.

When there are not enough pores or holes at the bottom of the pot, be sure that this evokes the black fungus in your soil. This results in a shortage of air and sunlight, which can also be the reason for their appearance.

In this article, I’ll explain what causes brown fungus in soil, whether it’s good or bad for your plants, and how to get rid of the brown fungus. Knowledge about these visitors can go a long way in maintaining healthy plants.

Is Brown Fungus Good Or Bad For Plants?

Brown fungus on Soil
Dog Vomit Fungus

Brown fungus, in most cases, is not good for plants when they grow on the plant itself; it can eat away and suffocate the plant.

They can pop up on garden soil and in potted plants as long as the conditions are right for them to grow.

How fungus affects plants:

  • It primarily affects the blossoms and young twigs of plants. It creates a lump on branches that may lead to the killing of the stem.
  • This fungus grows on fruits and affects them. Initially, circular brown spots are seen on the ripe fruits. Ash-grey-brown masses or clusters of the spores of brown rot fungus grow on the fruit.

    Hence, the fruit withers and shrivels. In this state, the fruit is called the black mummy. It then falls off or remains attached to the plant, causing further damage to the stem.
  • In the case of blossoms, it first causes the discoloration of those. Therefore, the entire flower turns brown, and spores grow on them. The affected bloom then wilts.
  • This fungus causes browning and wilting of leaves.

Check our detailed post, which covers fungus found on garden soil.

What Causes Brown Fungus In Soil?

The appearance of these molds is caused by the presence of certain microorganisms called filamentous fungi. These organisms are responsible for decomposing organic matter and producing nutrients such as nitrogen and phosphorus.

However, when conditions are favorable, these microorganisms produce spores that can survive harsh environmental conditions, such as overwatering and drought.

Once these spores land on the soil’s surface, they germinate and grow into mycelium. Mycelium is a network of filaments that produces hyphae. Hyphae are thin threads that extend outward from the mycelium.

The hyphae eventually break off and form spores. Some of these spores fall to the ground and take root. Others remain dormant until the right conditions occur again.

When the conditions are right, they germinate into mycelia once more. This process repeats itself year after year.

A warm and humid environment coupled with a good growing medium like decaying wood is a great environment for fungus growth.

Here are a few more things that assist in the growth of brown fungus in the soil:

Improper Watering

Over Watering

Over-watering is the primary reason that assists the growth of black fungus. When there is too much water in the soil, it may help the spores of the fungus grow faster. Hence, promoting the growth of brown fungus in the soil.

Drainage Problem

Improper Drainage

If your soil is too compact, it can promote the growth of brown fungus. Furthermore, if your pot lacks drainage holes at its bottom, or the pot you have used is too big compared to the size needed for good plant growth, there is a high risk of brown fungus growth as the water gets stuck in the pot.

Pollution in the Soil

There are various microorganisms and insects in the soil. If the soil is not cared for properly, the population of pests and microbes can increase in the soil and promote the growth of brown fungus. Moreover, the wilted leaves, blossoms, and fruits affected by this fungus can help its spores grow into fungus.

Absence of Sunlight


The absence of sunlight provokes the damp state of the soil. The high moisture content in soil contributes to the growth of fungus.

Restricted Ventilation


If there is insufficient air circulation in the soil, the water cannot dry out between the watering periods. It can be a reason for fungus growth.

Using Fertilizer


Use of organic fertilizer before planting or just after it may also trigger the growth of this fungus.

Types Of Brown Fungus:

Brown rot fungus can be of various kinds.

  • Hoof Fungus
  • Oyster Mushroom
  • Serpula lacrymans
  • Honey Fungus
  • Wet Rot
  • Chicken of the woods
  • Artist’s bracket
  • Turkey tail
  • Red-banded polypore and many more.

Here are some examples of them.

  • Coniophora puteana (cellar fungus)
  • Serpula lacrymans (true dry rot)
  • Fibroporia vaillantii (mine fungus)
  • Fomitopsis Pinicola
  • Phaeolus schweinitzii
  • Basidiomycota
  • Gloeophyllum trabeum and many more.

Agaricus bisporus is a brown fungus that is edible. Here are a few more.

  • Hen-of-the-woods mushrooms
  • Oyster mushrooms
  • Sulfur shelf mushrooms
  • Button mushrooms
  • Morel mushrooms
  • Portobello mushrooms
  • Shitake mushrooms

These fleshy mushrooms have high nutritional value. So, people prefer eating them for their savory flavors and fragrance worldwide. The best part is that they are hardly poisonous.

How To Get Rid Of Brown Fungus From The Soil?

Today, most homeowners rely on chemical pesticides to control brown fungi in their gardens. These products are typically sold in liquid or granular forms.

Most manufacturers claim that their product kills 99 percent of harmful fungi within 24 hours. However, experts warn that these claims are often exaggerated.

Furthermore, these products can pose risks to children and pets who come in contact with them.

We have outlined a few things you can do to control the occurrence of brown fungus without the use of pesticides.

You can follow a few necessary steps to get rid of this fungus.

Modify the Air Around

This brown fungus is fond of warm and humid environments. So, let your soil receive enough sunlight. Consider watering once a week. Regular misting might help in fungus growth in collaboration with the sunlight provided.

Do trim the weeds to improve air circulation to help the soil dry and save it from dampness.

Prevention is Better Than Cure

Use fungicide frequently to prevent fungi. Neem oil is known to fight out fungus like this. But do mix it with other liquids, or else the concentration will harm your plants.

Clean Your Soil

It is better to say goodbye to the already affected plants. Kindly don’t use them as compost, either. Please pick up all the fallen leaves, flowers, and fruits lying around your plant and fling them into the trash can. These residues feed the fungus. Wipe off your plant leaves daily.

Water Properly

Water your plants or the soil only when it runs dry in the first-inch depth. Check the moisture by digging your finger in it. There is no need for regular watering. It instead causes dampness which can lead to fungal growth.

Watering also encourages air circulation, which prevents the growth of fungus. Second, you should avoid fertilizing your lawn with manure. Manure contains bacteria that feed on decaying materials.

Soil Quality

Change the soil around your plants every 1-2 years. Use pure soil while planting a new sapling. Buying new soil might cost you a little but will help avoid infection from the impurities in the pre-used soil.

What are the best pest control methods for controlling brown fungi?

If you suspect that brown fungi are causing problems in your garden, contact your local nursery or gardening center.

They may recommend using a pesticide specifically designed to kill fungal species.

Another option is to use a broad-spectrum insecticide. Insecticides containing pyrethrin or spinosad are commonly used to control pests such as aphids, spider mites, and fungi.

While these pesticides are safe for humans, pets, and beneficial insects, they can harm bees and butterflies.

Does Brown Fungus Grow On Mulch?

Yes, the brown fungus can grow on mulch.

The brown fungus that grows on mulch is known as ‘Dog Vomit.’ It might not affect your plant much.

Fungus grows on mulch when there is excessive moisture in it. So, water your plants thoroughly once or twice a week instead of sprinkling.

Moreover, do not use affected plants as mulch. Organic mulch is no less than ambrosia to the fungus.

Lastly, don’t worry. Just dig out a few inches of the affected soil using a shovel. Fling it far away from your soil. Its spores are easily borne by air.

The Takeaway

Brown fungus grows in wet environments. The affected plant parts containing its spores can also be the reason for its growth when used as mulch.

Fresh soil may also start growing brown fungus as the fungus spores are airborne, and the soil may already have had existing spores.

So, keep your new soil away from the affected soil as far as possible and renew the old soil when needed.

Brown fungus can easily be removed by hand, but be sure to wear protective gloves.

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