What's happening inside your shiitake log?

The spawn that you planted on March 5, 2022 is growing very fine filaments called hyphae that are actively eating their way throughout the oak log. The network of hyphae, known collectively as mycelium, will run throughout the log for at least 12 months as the shiitake claims nutrients from the log. During this time the shiitake will develop specialized enzymes that will break down the long-chain biopolymers like lignin and celluose that make up the wood structure. If the shiitake mycelium encounter competitive fungi, they may combat the competitors with anti-fungal compounds. If the shiitake mycelium encounter competitive bacteria, they may create anti-bacterial compounds to stave off and defend the food they hope to consume.

When the mycelium colonize the log entirely, they store the moisture and nutrients until the conditions are just right for them to form “fruiting bodies”. The fruiting bodies are the mushrooms that we like to eat. The fruiting bodies are largely composed of chitin, a biopolyer that provides structure to the fungal cell walls. Ultimately, the chitin molecules come from the molecules of lignin and cellulose that the shiitake consumed and re-organized during the spawn run.

Every time that the shiitake make fruit, the mushroom releases stored resources into the environment. Sometimes you eat the mushrooms and the oak log becomes part of you. If you don’t get to it fast enough, the oak log becomes part of a squirrel or a slug in your neighborhood.

Here is a link to the presentation from my workshop where I introduced this process with help from this valuable book written by Tradd Cotter called Organic Mushroom Farming and Mycoremediation.

My 2022 log looks like a cut piece of wood with wax-covered holes along the edges.

The mycelium in this log from 2020 populates the entire log from end-to-end with the white mycelium that sometimes turns splotchy black. Little or no wax remains on the holes we drilled in 2020.

I noticed shiitake “pins” on my fully colonized log from 2022. Under favorable conditions, these pins may become full size mushrooms this week. Pins may come out of any spot on the log in whatever location suits the mushroom formation best.