Mushrooms in a log equals a tasty woodland harvest

Jaime Rowntree and Shane O’Donnell of Heartwood Mushrooms discuss the process of inoculating logs with shiitake or oyster mushrooms. The well-attended workshops are courtesy of the Manitoulin Community Fresh Food Initiative and Noojmowin Teg Health Centre with funding from the Ontario Trillium Foundation. photos by Michael Erskine

In addition to being nature’s amazing cleanup squad, mushrooms are a tasty addition for your dining pleasure and when in comes to putting these delicious fungi in your weekly mealplan, the fresher the better is a time-honoured catchphrase. With a little bit of effort (and a fair dollop of patience) you can ensure a steady supply of delectable mushrooms ready to delight your palate.

Shane O’Donnell and Jaime Rowntree of Heartwood Mushrooms recently held a series of workshops focussed on the fine (and oh-so-accessible) art of log inoculation. The Expositor caught up with the mycologist duo during one of the four log inoculation workshops sponsored by the Manitoulin Community Fresh Food Initiative and Noojmowin Teg Health Centre with funding from the Ontario Trillium Foundation and the Child Poverty Task Force Manitoulin Island.

The family-friendly workshops were open to everyone and took participants from “spore to table,” although Mr. O’Donnell admitted it was really more accurate to say from “spawn to table,” as the material used in the workshops to inoculate the logs actually contains the mushroom equivalent of seedlings technically known as spawn. “A lot of people associate mushrooms with spores,” he said. “It’s like the difference between seed and seedling. Like using seeds, using spores is more of a crapshoot on what you will get when the mushrooms develop. The biggest thing is ensuring consistency.” Using pre-sprouted spores known technically as spawn ensure a more consistent product at harvest time.

The mushroom log inoculation workshops focussed on two very popular varieties of edible mushrooms, shitake and oyster.

The first step in the process of creating your own mushroom log is finding the proper log to inoculate with spawn. “Hardwoods are usually the best for shitake and oyster mushrooms,” explained Ms. Rowntree. “The denser hardwoods like oak, ironwood and maple work well, but we also use poplar which can result in a quicker harvest as it breaks down faster, but will not last as long.”

Farming mushrooms with logs is quite economical, particularly if you have access to a wood lot and have the right tools to hand. “If you have a chainsaw and an angle grinder with the right bit, it doesn’t cost very much at all to get started,” said Mr. O’Donnell.

Once you have selected and cut down the type of log you plan to use, the next step involves cutting the log into sections that are easier to handle. Since the fresh cut wood will later be soaked, a section of around two-and-a-half to three feet is about as long as you want to get—the sections are quite heavy to manipulate otherwise.

The best time to harvest the wood is mid-to-late February as things are starting to move in the tree in preparation for spring. The wood will have to sit for a month or so in order to allow the natural herbicides in the wood fibre to subside. That natural fungicide protects the living tree from fungi and other invasive parasites. If the natural fungicide doesn’t fade by letting the log rest the tree’s natural defenses would play havoc with your crop since what you are planting, after all, is a fungi.

You might think that deadfalls would be a good choice, especially since they have been already sitting out the waiting time. But Mr. O’Donnell was adamant. “Do not use deadfalls.” 

“Stay away from deadfalls,” said Mr. O’Donnell. “You don’t know how long they have been laying there and who knows what kind of things have crept in that will contaminate or kill your crop.”

With your log cut and sufficiently aged, it is time for a good 24-hour soaking. Then you are finally ready to poke a lot of holes into the log, 60 to 80 to be inexact. The holes are slightly smaller than the width of a dime and are drilled in long rows down the length of the log, spaced about four inches apart. Each row is separated by about two inches and the holes are staggered down the length of the log. “Sort of like a diamond pattern,” said Ms. Rowntree.

When it comes to those aforementioned 60 to 80 holes per log—it’s a lot of drilling. “That’s why we use an angle grinder,” said Mr. O’Donnell. Although visions of slots cut down the length immediately spring to mind, the angle grinder is fitted with a special cutting drill bit that plunges about an inch-and-a-quarter into the wood, deftly poking 12 mm wide holes as fast as the grinder can be lowered into the wood.

“The angle grinder is rotating at thousands of rpm and the bit is designed to whip the wood out of the hole as fast as possible,” he said. Demonstrating the process with a deft and practiced hand, Mr. O’Donnell produces a row of holes in less than a minute. “If you were using a normal drill this would take quite a bit longer,” he said.

Once the holes have perforated the length of the log, it’s time to move on to the inoculating process. Ms. Rowntree passed around a bag of white streaked chocolate brown “sawdust” that contained the freshly “spawned” spawn. The bag weighs about five pounds and contains enough material to prepare between 12 and 15 logs.

“If you are only planning to do one log then you should maybe get together with a group of friends,” suggested Ms. Rowntree. “If you are not going to use all of the bag right away, put it in the refrigerator.” But even kept cool, the shelf-life of the inoculant isn’t going to be all that long so the group effort is probably the best route.

The inoculant is pushed into the prepared holes using a plunge tool, a thumb inoculator, a handmade spring loaded specialty tool that is readily available online. “We looked around at a lot of possibilities,” explained Ms. Rowntree. “These ones are the first we found that are made in Canada and they work really well.”

If you don’t have an inoculator, a wooden dowel of nearly the same diameter as the hole can be put into service. The inoculator makes it a lot easier.

Stabbing the inoculator into a bowl of the brown sawdust-like spawn material, the tool is then inserted into the top of the hole and pushed down, filling the hole neatly and completely.

Then it’s time for sealing. 

“We use bee’s wax, mostly because we happen to have it on hand,” said Ms. Rowntree. “But you can use cheese wax or any food grade wax.” Asked if paraffin wax is a suitable alternative, the mycologist responded that it can be used, but added a caveat. “Paraffin is a petroleum product. You can use it, but mushrooms break the wax down and do you really want to use a petroleum product in your food?” she asked.

With the holes well-sealed, the log is ready to be watered and set on its side somewhere up off the ground in a shaded location. Water the log well when it is set down and then check it a couple of times a week to make sure the log isn’t drying out too much. A good whack on the log with a mallet helps wake up the spawn and get them moving, but it is still going to be a while before you are enjoying the fruit of your labours. The log will sit for a year.

As the next spring gets itself sprung, the logs should be stood upright on an angle, again in a shaded space. Tiny pins will begin to appear as the mushrooms poke their way out into the air.

It takes about six weeks for the pins to mature. “You know they are ready to harvest when the gills on the underside of the mushroom appear,” said Mr. O’Donnell. “There is a tiny veil that covers the gills. When that is gone the mushroom is ready to spawn and that means it’s time to harvest.”

The first year will produce mushrooms, but it is the second and following years that are the best. “You might actually get some harvest the first year if you are using poplar and it is a very long growing season,” said Ms. Rowntree. “You can expect to harvest about once every six weeks—so three to four harvests a season. One hardwood log can last up to five years.”

Heartwood Mushrooms is currently building a facility on Cockburn Street in Little Current and they anticipate being in production sometime around late June, early July. But don’t drop in looking for products. “It isn’t a retail location,” said Mr. O’Donnell. “We will have a number of outlets around the Island available.”

The company will be supplying inoculant and can be found online at