Every Gardener’s Ultimate Guide to Soil Fungi

Are you wondering about the ability of fungi to improve your plant and soil health?

Do you know what the largest known creature on Earth is? It isn’t a redwood tree or a blue whale. It is the mycelium of a  humongous fungus measuring several hundred tons aged between 2,000 and 8,000 years. It covers up to 4 miles of the Blue Mountains of Oregon.

Having robust soil means more to a gardener than having mineral particles of the same shape and size. There are many things that can make the soil fertile. One of them is “fungi.”

Fungi are helpful and essential to plants as it creates the soil structure, works with beneficial soil organisms, fights the bad ones, and also helps to transport nutrients.

Is it possible that you might have been gardening for almost a year without noticing the presence of fungi in your garden?

Yes. In a year, you may not notice the presence of fungi in your garden until autumn starts. In autumn, the mushroom, which is the reproductive part of the fungus, starts appearing in your garden.

Fungi come in a huge variety of species and forms that can make it quite challenging and intriguing to understand them.

Before going further, let’s take a quick look at the highlights:

  • Fungi: What are they?
  • Classification and types of fungi
  • What do beneficial fungi do for your garden?
  • How do you know if you have fungi-rich soil?
  • How can you grow more beneficial soil fungi?

Fungi: What Are They?

Britannica defines fungi as widely distributed organisms with considerable environmental and medical value. Most fungi live freely in the soil or in water, while others form either symbiotic or parasitic relationships with different plants or animals.


They are eukaryotic organisms with cells containing membrane-bound organelles with clearly-defined nuclei. Fungi distinguish themselves clearly from other living organisms by their modes of nutrient intake and vegetative growth.

Do you often see mushrooms in your garden?

What you call a mushroom, is a temporary structure formed by some fungi to produce spores.


Typically, the main body of a fungus consists of web-like, fine-branching threads called “hyphae.” This network of web-like fungal hyphae is known as a “mycelium.” They are often hidden underground with individual filaments being a single cell wide.

Mycologists have identified no less than 70,000 species of fungi out of the 1.5 million species found worldwide, with about 6,000 interacting with plants’ roots.


Plants sometimes find it challenging to absorb key nutrients, such as nitrogen, phosphorus, iron, and potassium. Fungi, however, do not have this problem. On the contrary, they produce certain specialized enzymes that help to break the bonds binding the nutrients to the soil and other organic compounds.

This is an active process, referred to as “decay.” Gardeners can easily spot this decomposition in compost piles.

Soil fungi play many roles in your garden. Hence, plants with several miles of hyphae tend to mine essential nutrients and transport them to the roots. This explains why such plants always grow faster, look stronger, and yield more than those that do not partner with fungi.

Classification and Types of Fungi

Most people associate fungi with unwanted growth and health problems. They can be roughly divided into two types: the endomycorrhizal fungi that penetrate the cells of the root and the ectomycorrhizal fungi that remain outside the cells of the root. In both cases, the outcome is a continuous exchange of nutrients.

Fungi are classified into four types, namely:

    • Rhizopus
    • Neurospora
    • Agaricus
    • Fusarium

In addition to these, there are three fungi groups that every gardener and grower should be familiar with:

  1. Decomposers: 

Also known as saprophytic fungi, decomposers degrade the lignin and cellulose in the soil, helping to break down dead organic matter and convert it for plants to produce fresh growth.

Sugar fungi, known as Zygomycetes, help to decompose simple sugars. Some byproducts of decomposition become humus over time and remain in the soil for a very long time.

  1. Pathogenic fungi: 

Pathogens play two roles. They either reduce plant vigor or kill the plants entirely. Typically, you will notice pathogens if your young plants or seedlings ‘damp-off’ but still have considerable fungal disorders.

  1. Mycorrhizal fungi: 

These grow on or inside the plant roots to help the plants access nutrients. You can find mycorrhizal fungi in a place like Plant Revolution Inc. to use while planting shrubs and trees.

This kind of mutualistic mycorrhizal fungi forms a beneficial relationship with plants. Grasses, vegetables, shrubs, and row crops are often associated with mycorrhizae fungi.

  1. Saprophyte fungi:

These fungi help to recycle nutrients. They create rich soil for the plants to thrive in by breaking down organic matter. Although insects and bacteria help to foster this process, saprophyte fungi handle most of the life-supporting nutrient cycling.

What Do Beneficial Fungi Do For Your Garden?

Here are 5 things beneficial fungi can do for your garden:

  1. They Increase Nutrient Uptake

The formation of mycorrhizae increases the root’s surface area up to a thousandfold. The hyphae also help to increase the soil volume, as well as the nutrients, for easier access by plants.

More importantly, they provide the plant with phosphorus in a form that is more usable. Mycorrhizal fungi can break down any element that is tightly bound to the soil, returning the minerals to the plants in a usable form.

  1. Provides Help to Nitrogen-Fixing Bacteria

Rhizobia, a nitrogen-fixing bacteria, requires a substantial amount of phosphorus to fix nitrogen. However, the bacteria live and work on the coarse roots of legumes that may not be able to extract nutrients like phosphorus.

Making sure that you have mycorrhizal fungi will increase the availability of fixed nitrogen and phosphorus in the soil.

  1. Increases the Availability of Water and Boosts Drought Tolerance

Fungal hyphae have a microscopic diameter that enables them to harvest water from very tiny soil pores not accessible by the roots of plants. If you add more nutrients to the soil, the plants’ ability to survive periods of drought will increase. Mycorrhizal fungi are, therefore, a helpful solution to water restrictions.

4. Glomalin - Carbon Sink and Super Glue

Glomalin, a super sticky substance, comprises 30 to 40 % carbon and is only produced by arbuscular mycorrhizal fungi (AMF). It accounts for 27 % of the carbon stores in the soil.


        Furthermore, glomalin aggregates soil particles for increased pores, better aeration, more water intake, and easier movement of the roots through the soil. This makes the soil more resistant to water and wind erosion for more “tilth.”

        It also coats the surface of both the hyphae and fungal spores.

        How Do You Know You Have Fungi-Rich Soil?

        How can you be sure that your soil is rich in fungi?

        There is a simple way to determine this.

        • Method 1: Dig into your soil interface or mulch. The white strands you see in the soil are hyphae strands, mycelium, or the fungi body. However, if it is not absolutely necessary, it is advisable not to dig since this destabilizes and kills the fungi, exposing it and breaking its hyphae connections.

        However, if this is the only way to check for fungi, your soil will recover from the disturbance soon enough as long as it is well populated and the conditions are right.

        Do you find this method unsuitable?

        You can try a less intrusive method.

      • Method 2: After a warm dry spell, watch out for the first rain that soaks the ground.
      • What happens?

        Soil that is fungi-colonized will have mushrooms sprouting everywhere. It is always nice to see and indicates soil that is lively and rich in fungi.

        How Can You Grow More Beneficial Soil Fungi?

        Well, you already have fungi living in your soil.

        But what if it isn’t enough?

        Is it possible to multiply it?

        The more beneficial fungi you have in your soil, the better. Although you can’t see the fungi until it produces a mushroom, there are ways to encourage their development for richer soil and vigorous trees, shrubs, and perennials.

        Try these 6 tips. They will prove very helpful:

        1. Maintain your native fungi populations

        Beneficial fungi can be found in different gardens across the United States and are adapted to the climate, soil, and plant species. They tend to reduce if you engage in activities, such as the excessive application of fertilizer or pesticide, tilling, prolonged land fallowing, and the removal of woody debris or other plant litter.

        You may need to consider a commercially available product if your land has been tampered with by tilling or the application of herbicides. This is one of the best ways to improve tree strength and the survival rate of your plants.

        1. Stop tilling mechanically

        What do you use when tilling your garden soil?

        It is not advisable to use power tilling on your garden soil. Tilling your soil with power tools turns the soil and fungi into mushy, pulverized particles.

        Instead, use hand tools to till your soil, allowing you to easily turn the soil and mix in the fungal food sources. Whatever compost and mulch are available on the surface of the soil are also available to the fungi below.

        Over time, the fungi will reach the soil surface, digesting whatever organic material they find there, and transporting the nutrients to the plant roots.

        Learn a lesson from the forest. Although nobody tills it, it has a rich layer of fungal leaf litter that supports a wide variety of massive trees, plants, and shrubs.

        1. Feed it compost and mulch

        Fungi feed on tough organic matter. Therefore, you should use more organic mulches in your soil. You can foster fungi with anything from a tree, such as bark mulches, pine straw, fallen leaves, and dried fruits. Most of these items can be used to make compost.

        1. Use crop rotation and cover crops

        There are no plant roots in bare soil, meaning that the mycorrhizal fungi will experience famine. It could help to use legumes and grass as cover crops to capture nitrogen and provide a haven for soil fungi during the winter.


        By spring, the soil may not need these cover crops anymore as there would be lots of organic matter and a large quantity of healthy fungi.

        If you grow a vegetable garden, the soil fungi could partner very well with crops in the onion, corn, and bean families. With crop rotation practices, you can rotate these vegetables annually. This will keep the good soil fungi in your garden happy.

        1. Reduce or stop the way you use chemical fungicides

        Can chemical fungicides harm your garden?

        Well, actually they harm your soil fungi when used anywhere in your garden. 

        As much as possible, avoid using these chemical fungicides. You can look for suitable alternatives.

        If you find it hard to do without them, use them sparingly and carefully.

        1. Limit fertilizer use

        Is your soil very fertile?

        If you want to incorporate mycorrhizal fungi in your soil, you should reduce the way you apply fertilizer, and avoid those that are high in nitrogen and phosphorus.

        High soil fertility will reduce the development of fungi in your soil.

        1. Where appropriate, buy mycorrhizal fungi to inoculate your garden

        Yes! You can inoculate your trees with beneficial fungi while they are still in the nursery or while planting them out, using either granular or liquid products.

        Look out for the best mycorrhizal fungi products. Different types of plants require different types of fungi, while some plants don’t require any mycorrhizal fungi at all.

        When you buy mycorrhizal fungi, it is important that you check the label for a list of ingredients, as well as recommendations on which product works best for individual plants.

        So, Can Fungi Make You a Better Gardener?

        The answer is Yes!

        Fungi, the unsung heroes of every gardener, are a vital part of a natural ecosystem or an organic garden. In addition to allowing plants to communicate effectively with one another, they also cooperate with plants to ensure the effective distribution of water and nutrients.

        So, if you are unaware of all the roles that fungi play in your garden, and would like to learn how to maximize this valuable resource, contact Plant Revolution Inc.