Mushrooms: Are They Decomposers? (& Why They’re Good for Your Garden)

  • By: SFUAA
  • Date: May 5, 2022
  • Time to read: 5 min.

Although it may be distressing or unsightly to find a large cluster of mushrooms on your perfectly manicured lawn, there is a lot of evidence to suggest that mushrooms are good for your garden and seldom a sign of decay or potential damage. So are mushrooms decomposers, and why are they good for your garden? 

As a member of the fungi animal kingdom, mushrooms can be both primary and secondary decomposers. Therefore mushrooms are essential in breaking down organic material into soluble nutrients and vitamins to the benefit of plant and animal life. Thus mushrooms pose no harm to one’s garden. 

It is worth taking the time to understand the biology behind mushrooms/fungi to know why they serve an essential function in gardens and the greater ecosystem:

Mushrooms in the Garden | Source: Courtesy of My Mulch

Are Mushrooms Decomposers?

Mushrooms are unique in that they are separate from plants and animals; instead, they are a different kingdom of organisms known as fungi. While animals eat and digest food for energy, plants use a process known as photosynthesis to transform sunlight into usable energy. 

In contrast to plants and animals, fungi are spores that are spread through the wind or animal feeding. Once these spores land on a suitable substance such as wood, they will germinate and build a network of threads known as mycelium. 

The mycelium penetrates the new energy source, such as wood, releasing enzymes that digest the energy source externally (as opposed to the internal digestion of animal feeding). Once the energy source has been successfully digested, the mycelium absorbs the digested nutrients. 

As a result of this digestion process, mushrooms form the by-product and reproductive structures of fungi from which other spores are developed and spread. Therefore, mushrooms can best be described as the “seeds” or “fruit” of fungi’s reproduction process. 

Therefore, this process of food consumption, energy transformation, and reproduction makes fungi decomposers. Thus, by extension, mushrooms are decomposers. 

There are two different types of decomposers:  primary decomposers and secondary decomposers. Whereby other species of mushrooms may fall into either category.

Primary Decomposers 

As the name suggests, primary decomposers decompose organic material directly. These include: 

  • Wood decay fungi (white rot and brown rot), and 
  • Litter-decomposing fungi. 

Examples of mushrooms that are primary decomposers are: 

  • Winecap, 
  • Maitake, 
  • Oyster, and 
  • Shitake. 

Secondary Decomposers 

Secondary decomposers require a complex energy source, whereby they depend on the by-products and metabolic products of bacterial, fungal, and other primary decomposers.

Examples of mushrooms that are secondary decomposers are:

  • Paddy straw, and 
  • Common button mushrooms. 

Are Mushrooms Good For Your Garden/The Environment? 

Although decomposers at face value may appear to be destructive and detrimental to the wellbeing of your garden/the greater environment, they are, in fact, beneficial for various reasons:

  • Decomposition, 
  • Symbiosis, and 
  • Food Source Contribution. 


Because certain mushrooms are primary composers, this means that unlike other decomposers such as bacteria, mushrooms/fungi can penetrate more rigid materials that bacteria would be unable to break down. 

For example, lignin is a substance that safeguards the cells of dying trees, meaning that without mushrooms, this lignin would not be penetrated and subsequently decomposed. Therefore, mushrooms break down dying material and convert this wasted potential and clutter into richer nutrients. 

Not only is this decomposition a food source for secondary decomposers, but the secretion of digestive enzymes transforms organic compounds into soluble nutrients such as phosphates, nitrates, and simple sugars. 

Consequently, these soluble nutrients enter the soil and water, allowing plants to access a host of vital nutrients they would be unable to access without the assistance of fungi/mushrooms. 

In conclusion, fungi/mushrooms contribute toward a nutrient cycle that removes organic compounds and transfers their potential into nutrients to benefit healthy/thriving plants.


In a process known as mycorrhiza, plants and mushrooms develop a unique symbiotic relationship, whereby they assist each other without causing harm to one another. 

Mycorrhiza is when mushrooms occupy the tissue of a plant to gain direct and consistent access to carbohydrates, which in turn promotes the growth and development of mushrooms. 

In exchange for this occupation, plants acquire access to the mycelium of the mycorrhizal fungus; this allows plants to access vital, soluble nutrients that they ordinarily would not have access to. 

Approximately 95% of all plants can form a symbiotic relationship with mushrooms (assuming it’s not dead foliage), whereby some plants owe their existence and continued survival to mycorrhiza.

Food Source Contribution  

In their own unique kingdom, fungi/mushrooms provide a unique food source to various animals and insects. Their existence denotes an inherent good to the diversity of an area’s food web, but it also means that animals/insects that are beneficial to your garden will be drawn to it. 

Alternatively, animals/insects that may prove harmful to the wellbeing of our garden may opt to eat mushrooms rather than consume your healthy plants.

Are Mushrooms Bad For Your Garden?

Although mushrooms are good for your garden most of the time, too many mushrooms may prove unsightly and/or have unpleasant features (such as stinkhorns that release a foul odor to attract flies!) 

Mushrooms can also become overgrown, with their hyphae being so thick as to prevent air and water from getting down to the grassroots, thus causing green grass to turn brown in patterns known as “fairy rings.”

Finally, the presence of toxic/poisonous mushrooms may pose a threat to any pets or children that may frequent your garden. 

If you believe excess mushrooms may be causing damage to your garden or pose a health risk, the following garden tips can help manage fungi populations:

  • Manually removing mushrooms to reduce the spread of spores, 
  • Reduce irrigation to avoid creating damp conditions where mushrooms thrive, 
  • Remove excess thatch and aerate the soil to improve water penetration and air movement, 
  • Apply nitrogen fertilizer to speed up the decomposition of grass, tree leaf clippings, and other organic debris in your garden. 


In conclusion, as both primary and secondary decomposers, mushrooms/fungi serve an important ecological role. Therefore, mushrooms in your garden are usually a good thing, provided they are managed correctly.

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