Mushrooms Growing in Worm Bin

A mushroom that grew in my big outdoor worm bin a couple of summers ago.

Here is a question from Maggie:

So i was checking on my closed bin worm compost and noticed
tall thin white mushrooms!! Is this normal? There are some fruit flies
in my bin and there are no bad smells. In fact I love the fresh earth
smell!!! A little background, I started regular composting then after
2 or 3 weeks decided to add worms. I had about 15 pounds of food and
added 2000 worms give or take. And they have been in their new home
for about two weeks. I have dug around and there are worms wiggling
about near the top, I havent gone more than 2 inches down. But
everything seems ok!! I guess im just nervous that I am going to end
up with a pile of garbage instead of wonderful compost!! Thanks for
your help and any advice and I LOVE this website, VERY helpful!!!!

Hi Maggie,
Have no fear! This is very normal – as you can see (in the picture above), I’ve had this happen myself. Mushrooms are of course the fruiting bodies of various species of fungi. In a composting ecosystem there are a LOT of different types of fungi at work, so there is a lot of competition for resources. This is probably why you don’t see mushrooms popping up all that much. Aside from that, when there are worms in the system, they generally wreak havoc on fungal mycelia (the networks of fungal material) simply via their movement – not to mention the fact that they likely graze directly on it. As such, it would likely be more common to see mushrooms pop up in a passive compost heap containing no worms.

That being said, certain mushroom-producing fungi also have a particular affinity for carbon-rich materials, such as those used for ‘bedding’ in a worm bin – shredded cardboard, newsprint etc. Since worm composting systems are often rich in these sorts of materials, it’s not too surprising to see these fungal species briefly taking advantage of this resource.

Believe it or not, I’ve read an account of someone who apparently grew edible mushrooms in a worm bin and harvested a pretty good crop over the course of several months. I am quite surprised by this, given the competition and worm activity, but I’m actually somewhat curious to try it out myself.

Anyway – hope this helps, Maggie!

Written by Bentley on April 15th, 2009 with 2 comments.
Read more articles on Reader Questions.