It seemed to me that the best way to solve all of these problems was to put plants and mushrooms in the same pot. After all, this is how it works in nature, right? The fungus lives in the soil, breaking down organic material and the plant lives above, using nutrients, providing more organic material for breaking down, and shading the soil to protect the fungus. The two are also extremely complimentary in terms of exchange of oxygen and carbon dioxide. The plants provide the oxygen the fungus needs, while the fungus provides a slow release of carbon dioxide where the plant needs it. But, if you are going to grow the two together, what do you do about growing medium? If you put soil in there, especially potting soil, the mushrooms don't have much to grow on. If you put wood chips, most mushrooms' preferred growing medium, in there, the plants don't have the nutrients they need to grow. The mushrooms will break down the wood chips, but not fast enough to give the plants what they need to grow. The picture below is of a pot that is growing just mushrooms, with no worms and no plants. This particular mushroom, oyster mushrooms (pleurotus ostreatus), has killed every plant I have tried to put in with it, so I quit trying. The mushroom has been in the pot and producing mushrooms for almost two years. As you can see, the wood chips on the surface are still quite visible and there is really no actual soil in the pot.
To solve the conundrum, I came up with myco-vermicomposting. I chose a large pot and put a log, inoculated with mushroom mycelium, in the pot. I surrounded that with wood chips and also inoculated that with the mycelium. Then I planted a plant down in the wood chips. In the case of the pot you see in the picture below, I planted a calla lily. Over the first year, the calla lily was weak, slow growing, pathetic looking, and prone to pests, particularly spider mites. During that time, the mushroom was processing both the log and the wood chips. The worms were working hard on the mushroom mycelium and, to a lesser extent, on the wood chips. At about one year, the plant just exploded with growth. It turned bright green, tripled in size and no longer had any problems with spider mites. By that point, the wood chips had been turned into a deep black soil composed almost entirely of compost.
I eventually dug the calla lily out of the pot because it was overtaking my entire plant area and using a full gallon of water a week but never flowering. The small leafy plants you see in the picture are a resurgence of the plant from the roots I left in the pot to decompose. The grassy plant in the picture is a lemon grass. It isn't very happy, but I haven't figured out if that is because of a need of fertilizer, a lack of full sun, or the fact that the cat keeps eating all its new growth.
So, here are a list of things I learned about myco-vermicomposting, things to keep in mind if you try it yourself.
1) The worms will reduce the number of mushrooms you get from the wood chips by at least half. I don't think they can really get into the log to steal from there. They eat the mycelium, weakening the mycelium and reducing its ability to produce mushrooms. So if you are doing it for mushroom production, have more of a two-bin system. Let the mushrooms grow alone on the wood chips first, then let the worms have a crack at it to finish it off. If you try the worms first and then the mycelium, the worms get a lovely snack and you get no mushrooms at all. I tried inoculating a worm bin with some mushroom spawn that I didn't really have plans for. I came back a few days later to see if it had taken off and it was completely gone. The worms had eaten it.
2) As the raw material decomposes, the soil level drops considerably, so you will have to add more organic matter. Depending on the size of your pot, this could cause the plants to sink down with the soil, causing problems when you add more organic material.
3) The mycelium pretty much goes through its whole life cycle in the soil early on, so they won't really get into further applications of wood chips, unless you get mushrooms off the logs and the spores get into the wood chips. But you can't really count on this, and you certainly can't count on only your mushrooms getting in there. There may be contamination. So it might be best for future applications of organic material to be geared towards the worms. They'll keep going.
4) Lately some of my plants in the compost have been kind of pathetic looking. I think it might be due to the nutrient content of the soil. After all, it was made from pure wood chips. I haven't had a chance to test the soil, but my guess is that it is a little low in nitrogen at least and possibly potassium and phosphorus. I would recommend the addition of a good organic rock-based fertilizer regularly with the various layers of organic matter that you add. The rock-based fertilizer, such as greensand for potassium and rock phosphate for phosphorus, will have more staying power in the soil than the quick-fix type fertilizers. I don't know of a rock-based source of nitrogen, so I use blood meal. They will also be good for the mushrooms that you get in there, as they are used to breaking down rock for minerals. A little sand or pea gravel in the layers might also be good to help out the soil structure. Of course, ignore this if you are composting in one place and using the compost elsewhere.
5) As the soil breaks down and your primary mushroom-producing fungus moves out of the soil and into the log, an addition of mycorrhizal fungus to the plants will introduce another player to the party, one that will help break down more organic matter, help the plant, and is more adapted to living in soil. I'll cover mycorrhizal fungus in a later post.
So, what's next? The mushrooms that break down wood chips are primary decomposers. There are also secondary and tertiary decomposers. I'd love to try a tertiary decomposer in the pot and see if they produce anything. The big thing on the horizon, though, is my bioneering laboratory. Unfortunately, it is still a year to two years off before I can begin construction