Learning How To Turn Wood Into Delicious Edible Mushrooms
In autumn 2013 we began our first foray into the world of homegrown gourmet mushroom production. We had been felling a lot of trees on the Tap o’ Noth Permaculture site to reduce some of the shade around our vegetable gardens and to provide fuel to keep our home warm in winter. And while we were processing the timber into firewood we thought we would keep some logs aside to use them as a substrate to grow edible mushrooms, in this case Shiitake. We chose Shiitake for their reputed health giving benefits, their flavour and, from what we have read, it is one of the easier mushroom varieties to try cultivating. We found the process of inoculation to be relatively simple and we have outlined the way we prepared our logs below.
To date (Dec 2014) our logs have not yet begun fruiting but we will be sure to post an update when this happens.
Shiitake is best grown on hardwood logs, oak or beech being the prefered substrate. We chose a mix of beech and cherry as that is what we had onsite and available to us. It’s important to only use healthy wood, cutting the selected logs no more than six weeks before inoculation. This reduces the possibility of ‘rogue’ fungi inoculating the logs before you introduce the Shiitake spawn. With this in mind, using logs that have been on the forest floor is not advisable so always cut fresh branches/logs. Straight logs anywhere between 50 cm – 1 meter in length and 10-15 cm in diameter are best, any bigger and they can be rather difficult to maneuver.
We have bought our Shiitake mycelium from Mushroom Box and Anne Millers Speciality Mushrooms in the form of wooden dowels already inoculated with the Shiitake mycelium. On websites like these you can also buy all the equipment you’ll need like wax, drill bits etc. Quite often you can purchase a starter pack containing everything you need to inoculate your logs which is a convenient option. For larger production projects it can be more economical to buy sawdust already colonised with spawn which can then be used to inoculate logs using a special inoculation tool rather than dowels. In this instance we used dowels.
When you receive your dowels it is best to keep them refrigerated until use. Best thing is to have the logs ready and get to work as soon as the dowels arrive.
We found it helpful to place the chosen log on a sawhorse, allowing for good stability while you clean and prepare it for drilling. It’s important to clean off any soil, lichen or loose bark before you start drilling holes for the dowels. A wire brush is a good tool for this job. Make sure there are no large areas of damaged bark or signs of insect infestation.
Once the log is clean of debris it is time to drill some holes to accept the wooden dowels. We drilled the holes roughly 15 cm apart down the length of the log starting 10 cm from the end of the log. The log can then be rolled slightly and the next line of holes can be drilled, staggering to allow more space for the mushrooms to fruit. For a log of 1 meter aim to use around 20 dowels.
Using a mallet or hammer, the wooden dowels are tapped into the holes, leaving them flush with the surface of the log.
Once the dowels are all in place the next step is to cover the dowel and any scars on the wood with melted wax. You want the wax to be really hot, effectively sterilizing the area and sealing in the dowel. This prevents any other fungi from entering the drill holes and contaminating the log. We melted the wax in a tin can on top of the stove and used a paintbrush to apply the wax.
Once the whole log has been drilled, dowels fitted and waxed, it’s time to find a the right place to leave your logs and wait for them to fruit. You want to imitate forest conditions, looking for somewhere with dappled shade where the logs will not dry out.
Fruiting time will depend on your choice of timber – the harder the wood the longer it will take the mycelium to colonize the log and fruit, though mushrooms grown on hardwood will produce for a longer time period than a on softer species of wood.
Our mushroom logs are sitting in a shady area of our forest garden and we are waiting patiently for the first signs of fruiting to occur. We will be sure to update you as soon as the first Shiitake mushrooms appear.