Starting a Mushroom Log

Starting a mushroom log is a pretty simple process. All you do is introduce the mycelium to the wood and give it the right conditions to grow. The process can be done with spores, but it is extremely unreliable. Therefore, it is much better to use living mycelium. There are many different methods for doing this, and I will cover two here, the first for using plug spawn and the second for using sawdust spawn. But before you try this make sure you have read my post on matching type of wood to type of mushroom.

Plug Spawn

Plug spawn is mycelium grown onto small wooden dowels that is then pounded into a hole drilled in a log. They are available online or can be made yourself, which I will cover in a future blog post. The advantage to plug spawn is that they are relatively inexpensive ($15 or so for enough to inoculate about 3 logs last time I checked) and really easy. You just drill a hole in the log, making sure to go deep enough that the plug can be fully inserted in the log and preferably sunk deep enough to be inside the bark. Once the plugs are inserted in the log, the fungus leaps off from the plugs and quickly colonizes the log.

For this method, all you do is drill a hole that is just a tiny bit bigger than the plug and hammer in a plug. Too little space and the plug won’t go in, while too much space doesn’t give enough contact or protection for the mycelium. A snug fit ensures that nothing can get between the plug and the log to disturb your mycelium. Plugs should be spaced every 3”-6” and placed in a diamond pattern around the log. The closer together you put the plugs and the more plugs you put in a log, the faster the mycelium will colonize the log.

Living in a dry climate, keeping my logs moist is a major consideration. I like to get a large pot, the kind you would put a plant in, and put the log upright in the pot, making sure one half to one third of the log is down in the pot. Then I fill the pot with pasteurized wood chips or sawdust. A few plugs scattered into the sawdust helps the mushrooms colonize the sawdust. Once it has, it just moves into the log faster. Personally, I don’t like the look of all the holes drilled in the log, so I only plug the log below the sawdust line. It hasn’t been a problem yet. I probably wait a little longer for my mushrooms, though.

There are also several steps that are not necessary but are helpful. Beeswax is a great help to the process. If you pour melted beeswax on the cut faces of the log, it helps retain moisture and prevent spores from competing mushrooms get a foothold. Also, you can fill the holes with beeswax after you have inserted the plug. This also helps retain moisture and thwarts bugs and worms that like to get in there and eat the mycelium. Another step I like to do just to be safe is to spray the outside of the log with hydrogen peroxide. Hydrogen peroxide is toxic to fungal spores that may have landed on the bark and are sitting there waiting for conditions to be right (just like you are about to do to your log). Adding the plugs instead of sprouting from spores gives your mushrooms a clear advantage, but I prefer to be safe anyway.

Sawdust Spawn

Sawdust spawn is mushroom mycelium growing on sawdust. It can be purchased as sawdust spawn or it can actually be a spent mushroom kit. It is a little trickier than plug spawn. It can’t exactly be hammered into a hole. Plus, it is kind of messy. One common method of making mushroom logs with sawdust spawn is called the wedge technique. You use a chainsaw to cut wedges out of the log, alternating sides up the log. Then you pack the cut with sawdust spawn and nail the wedges back in. I have two problems with this method: 1) I don’t own a chainsaw (I know, bad Mad Bioneer), and 2) the aforementioned dryness problem. So I modify the method a bit for my situation. I still cut the wedges, but I use an axe instead. Also, just like with plug spawn, I put the log upright in a pot and fill it with pasteurized wood chips and sawdust. I take the wood chips that I cut out of the log in the first place and mix them with some more wood chips and pasteurize them. Then I mix the sawdust with it and pack it around the log in the pot. The mycelium will rapidly colonize the sawdust and then use the surface area of the wedge to colonize the log.

Coming soon: Care and Feeding of Your Mushroom Log