Grow mushrooms the EZ way.

White fuzz on mushrooms – Safe to Eat? Growing Advice?

White fuzz on stem of mushroom

Introduction

Two types of people are looking at this article, people who have white fuzz on mushrooms they are about to eat, and people who are growing mushrooms which are developing white fuzz on their stems.

This article is for both types of people so that they can figure out what the fuzz on their mushrooms are, and what to do about them.

What Is The White Fuzz On Mushrooms?

The white fuzz growing on your mushrooms is either one of two things:

  • White mycelium growing from the mushrooms body.
  • Mold growing on top of your mushroom.

If the white fuzz on mushrooms is growing from the mushroom stems it is called mycelium. It is a mass of thread-like filaments that make up the body of a mushroom.

The mycelium helps the mushroom absorb nutrients from the soil and also helps protect it from predators.

Mushrooms are the “fruits” of huge mycelium networks so, as you look and say “what is all this white fuzz coming off my mushroom” the mushroom was actually produced by those tiny white strands.

Actually, you are about to eat the white fuzz's reproductive system.

Hopefully that little fact hasn't put you off your dinner!

Is The White Fuzz On Mushrooms Edible?

Probably not, it is best to air on the side of caution if you have white fuzz coming out of store bought mushrooms.

Its either mycelium, or a moldy mushroom and realistically its not worth taking a risk if you are not 100% sure.

I am going to show you how to differentiate this. 

  • Is the mushroom surgace slimy and wet? If so the mushroom has probably gone bad.
  • Is the white fuzz growing out from the mushroom or lying on top of it? Check the picture below for comparison.
  • Does the mushroom have brown marks or other dark spots? The mushroom has probably gone bad.
  • Does the mushroom feel soft when you hollow and soft when squeezed? Bad
  • Is the mushroom shrivelling and wrinkled? Its gone bad.

Here are some pictures of moldy mushrooms (with white fuzz).

Its Mold.

white fuzzy mold on mushrooms

This mushroom has dark spots, it is slimey and there is white fuzz (its actually blue in the right light, but white to human eye) growing on top of it. This is a bad mushroom. 

white fuzzy mold on mushrooms
Blue Thrichoderma on mushroom

Here you can see the mold has developed and turned green. You can also catch how the white mold is infact blue/green mold you would find on bread.

Mycelium White Fuzz (a good mushroom)

If you are lucky the white fuzz is just mycelium growing from the stem of the mushroom. This white fuzz will look more like hairs and fillaments growing outward rather than resting on top.

For some mushrooms such as the lion's mane mushroom the mycelium is actually considered to be the most valuable tissue.

Ensure the white fuzz is coming from the mushroom and isn't a mold colonizing on top of it, see the picture below for an example.

White fuzz on stem of mushroom
Millet agar wedge

Here is another picture of what mycelium looks like growing from agar. It grows out in a linear fashion and looks more like hairs coming out of a mushroom rather than sitting on top of it.

White Fuzz On Mushrooms Whilst Growing or Cultivating?

Totally normal, finding fuzz (mycelium) on the stem of the mushroom is totally normal and nothing to worry about. 

Basically the fruit has developed extra mycelium to absorb some humidity and fresh air from its environment,this will in no way affect your growth.

Alongside this, the image above contains a mushroom found in the wild growing a white fuzz coming off it, so don't worry about it!

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