Monday, March 29, 2010
Myceliating the Compost
A month or so ago, I built myself a compost tumbler out of a 55 gallon plastic barrel. Don’t worry, I’ll tell you how in an upcoming post. The new composter gave me a place to put the bags of fall leaves that had not yet found a home. It took some doing, but I managed to get them all in there and there was just enough room to keep putting in kitchen scraps. However, spring has just barely sprung here and we are still in the grip of cold nights. So after a month of being full and being turned every few days, I have thoroughly moistened leaves that are a little more crumbled. No noticeable decomposition has occurred. Even the kitchen scraps are still green and mostly undecomposed. They actually look like they would if they were slowly going bad in the refrigerator.
I decided I didn’t want to wait that long for finished compost, so I decided something needed to be done. But how do you get it moving? A very high carbon content and negligible nitrogen content combined with low temperatures means that I have no chance of getting the thermophilic bacteria to start doing some serious cooking for me. I ended up with some worms in there due to transferring other compost in, but it is even too cold for them to do much work. However, there is another organism that can and will thrive in such conditions. Mushrooms make a living by competing in environments that other organisms cannot. They eat what few else can. Their main competitor is bacteria, so many of them evolved the ability to keep growing and digesting even when the temperatures are so low that the bacteria are all dormant. In doing so, they use the winter to gain a competitive edge. The enoki mushroom, also called the winter mushroom, is particularly good at this. You can grow them outdoors in the cold of winter and even fruit them (get them to produce mushrooms) in your refrigerator. I didn’t happen to have any enoki mushrooms growing, and even if I did, I am not sure they can survive on leaves in the compost bin. However, I did have oyster mushrooms growing on a roll of toilet paper as an experiment I did with the kids. Oyster mushrooms are relatively cold tolerant. More importantly, they will decompose just about anything with a high carbon content and do really well in compost bins.
So I decided to make a mycelial bomb for the compost bin. The most important consideration in this was protecting the mushrooms from the bacteria and earthworms already in the compost bin. Once disturbed, the mushrooms will take a few days to recover and begin growth. When they do begin growing, they will do so vigorously, but during that recovery period, they are vulnerable to bacterial competition and especially vulnerable to the worms. I have dumped mushroom spawn directly into soil or compost where worms are present only to have them disappear in a day or two because the worms ate them. So I decided to give the mushrooms a protective casing. I had saved an old worn out pair of 100% cotton pants for just such an occasion. I cut one of the legs off of the pants and tied one end of the leg shut with cotton string. Then I took some of the drier leaves from the compost and made sure there weren’t any worms in them and stuffed them in first. I followed that with the myceliated toilet paper roll, cut in half to increase surface area. Finally, I stuffed in more leaves and tied the other end shut. The fabric of the pants will keep the worms out long enough for the mushrooms to get a foothold inside the pant leg and then use it as a platform to leap off into the compost. The mycelium will have no trouble growing right through the fabric and out into the compost. In the process it will digest the pants and string, which will just become part of the compost.
Now I just have one little problem. Since last year, fruit flies and fungus gnats have been a major problem in my compost. They take up residence and swarm when I come by, making it unpleasant to work around the compost. They also get in the house and drive my wife nuts. I was going to get me some beneficial nematodes and let them take care of the fruit flies and gnats for me. The problem is, oyster mushrooms eat nematodes. So I guess I need to find some and get them and let them do their job before the mushrooms completely take over.