What Do Mushrooms Eat?

You might have learned somewhere that mushrooms are entirely different from plants, but what makes them different? And if you are thinking about growing your own, you must be wondering what do mushrooms eat?

Mushrooms make their food by breaking down organic matter like decaying plants into a form they can absorb. Unlike animals, mushrooms don’t have stomachs, nor can they make their food from sunlight as plants do. 

Mushrooms growing

Types Of fungi And What They Eat

People sometimes use the words fungi and mushrooms interchangeably, but this isn’t wholly correct. Fungi is one of the five kingdoms of living organisms, and mushrooms are fruiting bodies part of a specific group of fungi. The other microorganisms that form part of the fungi kingdom but are not mushrooms are yeasts, molds, and mildew.

An easy way to remember the difference between fungi and mushrooms is that all mushrooms are fungi, but not all fungi are mushrooms.

Fungi are categorized based on how they get their nutrients and feed themselves. For example, do they need decaying plants or a living host to survive?

Saprotrophic Fungi

Saprotrophic Fungi play a vital role in the ecosystem because they break down organic matter in the environment. They do this by attaching themselves to decaying plants, for example, which they convert into nutrients. By doing this, they create compost that enriches the soil and benefits the surrounding plants and trees.

Many of the mushrooms we eat belong in this category—such as oyster, shiitake, morels, and button mushrooms.

a bowl of button mushrooms, an example of saprotrophic fungi
Button mushrooms

Mycorrhizae Fungi

Mycorrhizal mushrooms form a symbiotic relationship with trees and plants in order to survive. In short, the trees provide the fungi with essential nutrients, and the fungi provide their host with water.

To do this, the fungi’s underground root system (the mycelium) connects with the roots of the plant or tree. The mycelium either wraps itself around the host’s roots, or sometimes the mycelia can be weaved into the host’s root cells.

In this way, the fungi extract nutrients from the plant but act as an extension of the plant’s roots. As a result, the plant now has a much longer network of underground roots covering a larger surface area so it can extract more water and nutrients from the ground.

The plants and trees that have this symbiotic relationship with mycorrhizal fungi grow much larger and faster than those that don’t. These fungi can be tough to grow because of this particular relationship with plants and trees. Therefore, you’ll find most of these fungi seasonally in the wild.

Parasitic Fungi

Similar to mycorrhizal fungi, parasitic fungi need a host in order to survive. However, it’s not a beneficial symbiotic relationship as it feeds off the insects, animals, or plants they take on as hosts. In many cases, it will not only be detrimental to the host but also lead to its death.

While many species of parasitic fungi affect trees and other plants, there are some that attack other mushrooms. It’s also possible for animals and humans to pick up a parasitic fungal infection.

One of the most common examples of parasitic fungi is Lion’s Mane mushrooms. This type of fungi feeds mostly off the bark of trees.

Lion's Mane mushroom growing on a log is an example of parasitic fungi

Endophytic Fungi

Endophytic fungi also have a beneficial relationship with their host. It relies on the host to provide it with the sugars and other substances it needs for growth. In return, the fungi provide toxins to the plant and help protect it from diseases.

In these cases, the toxins aren’t detrimental to the host plant. Instead, it protects the plant from being eaten by herbivores like cows and insects.

How Do Mushrooms Get Their Food?

Plants produce their food from sunlight using chlorophyll, and animals’ stomach digests food. Fungi and mushrooms follow a completely different process to get their food. They don’t have chlorophyll, nor do they have stomachs.

They get their nutrients in three different ways depending on the type of fungi or mushroom:

  1. Fungi feed themselves by absorbing the nutrients they need from the non-living organic material that they live in. Organisms that do this are called saprotrophs.  They do this by breaking down organic materials like decaying plants or animal matter into simple molecules that they can easily absorb.
    This process is essentially composting. Saprophytic fungi such as oyster mushrooms and shiitake mushrooms start this decomposing process by releasing enzymes from hyphal tips (hypha are the long branching structure found in fungi – the mycelium is made of a group of hypha). 
  2. They get their nutrients by feeding on living hosts. In this case, the parasitic fungi use enzymes to break down the living tissue of the host instead of dead plants. Unfortunately, this process usually causes illness in the host.
  3. They get their nutrients from another organism without harming them. In return, the hosts also benefit in some way.  These are the endophytic fungi discussed earlier.

What Nutrients Do Mushrooms Need To Grow?

Mushrooms extract the nutrients they need from the organic material they live in. The nutrients are primarily starch, sugar, fats, protein, nitrogen, and lignin. Lignin is the organic polymer found in the cell walls of many plants and gives them firmness and woody texture to their cells. Mushrooms also need oxygen and a specific pH in order to grow.

Those are only the high-level nutrients mushrooms need, but those of you that are interested in delving a bit deeper into the science of how they grow will find that they need a whole variety of elements to truly flourish.

Two of the main macronutrients fungi need for their structural and energy requirements are carbon and nitrogen. Other vital elements are Phosphorus, Potassium, and Magnesium.

While, in general terms, all mushrooms need the same nutrients, they also need different types of organic material available in order to be able to extract nutrients.

For example, button mushrooms can extract the nutrients they need from compost made out of manure and straw. Shiitake mushrooms, in turn, need wood or sawdust. They won’t be able to extract the necessary nutrients if they are grown in the same material as button mushrooms.

Final Thoughts

Mushrooms take the nutrients they need to grow from the organic material around them. Depending on what type of fungi they are, they’ll have a different way of extracting what they need from their environment. Most of the mushrooms we know and eat are saprotrophic. This means they break down organic matter around them and convert them into nutrients.

If you’re looking into growing your own mushrooms, it’s important for you to know that besides organic material to extract nutrients from, they also need oxygen and ideal PH levels.

Depending on what type of mushroom you’re interested in growing, you will need to supply the specific organic matter that will give the mushroom the right nutrients to grow. For example, oyster mushrooms will need different materials to grow than button mushrooms, so make sure you do some research before growing your own.

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