The Japanese have cultivated shiitake mushrooms on logs for more than 1,000 years. In the beginning, a live Japanese chinquapin tree would be cut down and dragged alongside a standing tree full of wild shiitake mushrooms. “Shii” means oak and “take” means mushrooms in Japanese. Spores from the standing tree would disperse and inoculate the fallen tree.
Sometimes this was done when a male child was born so he would benefit from this growing treasure.
A horticulturist wrote the first book on shiitake growing in Japan in 1796. So in a global sense it’s not a “cutting edge” crop. But it has always been a highly desirable one. Stories are told in Japan of shiitake wars that started when people stole logs rather than starting their own.
But shiitake mushrooms have become cutting edge in Western countries in the past few decades. They now constitute about 25 percent of yearly mushroom production worldwide.
The shiitake (Lentinula edodes) is also a wild mushroom in Asia, but it’s not found in the wild here. So any shiitakes you see in the market or on a menu are cultivated, which hasn’t kept some chefs from describing a dish with shiitakes or cultivated oyster mushrooms as containing “wild” fungi. But I hope as mycophage diners get better educated, we’ll see less of that.
Meanwhile, North American growers are turning their woodlands into productive and profitable shiitake mushroom farms.
Agricultural extension agents and other experts no longer recommend dropping and dragging live trees as a growing technique, but they do suggest lots of cutting, drilling, packing, stacking and dunking of logs. One could set up an entire CrossFit regimen around growing shiitakes. (And if you could recruit workers by offering it as a CrossFit class—“Forget Forest-Bathing! Get a First-Class Workout with Shiitake CrossFit Training!”—you might add a second income stream. Maybe.)
Here are the basic steps involved:
- Choose a cold-weather or warm-weather strain of shiitake spawn based on your climate.
- Get or prepare the spawn in the form of wooden dowels or sawdust, depending on preference.
- Secure a load of logs of appropriate species and size.
- Drill holes along each log. Proper depth and diameter of holes depends on Step 2.
- Insert spawn into holes.
- Seal holes with melted wax to keep competing fungi out.
- Soak logs overnight (unless they are freshly cut and very heavy with moisture already).
- Stack in your preferred pattern under at least 80 percent shade from trees or shade cloth.
- Spray with water periodically to keep them from drying out.
- Learn patience.
- Once the cut ends are covered with mycelium (about 6 to 12 months for oak) dunk the logs for 12 to 24 hours and re-stack.
- Mist daily to keep moisture level up.
- After a few weeks, cut the fruiting mushrooms while the caps are still young and concave.
- Cook and serve or package and sell.
Which Logs When (and How Big)?
It’s best to cut your logs in winter, when they have more sugars and less moisture than during their growing season. Best sizes are 2 to 4 feet long by 6 to 10 inches wide, depending on how much weight you can handle.
After cutting, wait a week before inoculating them, so the trees’ antifungal defenses can whither away. Also, inoculate them no later than four weeks after cutting live wood so competing fungi won’t have time to invade.
Shiitakes prefer dense, deciduous hardwood trees such as oak. A 6-inch diameter log of white oak is dense enough that it might fruit for as long as six years if well tended, or very roughly one year of production for each inch of diameter.
Lighter (softer) hardwoods such as poplar, birch and alder fruit less than oak. Word of mouth indicates that sweet gums might be the wood that shiitake colonizes most quickly. But again, as a lighter wood, it doesn’t produce as much.
Perhaps sweet gum is a good species to start with for a quicker turnaround when you’re getting started (or if you have a lot of it you want to get rid of). Overall, white and red/black oaks provide the best return on your effort.
However you get your logs, make sure “they have their pants on,” as some growers say—meaning the bark should be intact and cover the entire length of the log. That helps keep moisture in and competing fungi out.
Ways to Stack Logs
In your laying yard, stack the logs to get them off the ground and make easy access for mushroom picking. The two most common patterns are called “A-frame” and “crib” or “log cabin” style.
For the A-frame, a horizontal pole or cable can be set about waist high and the logs lean on that like so many staggered roof rafters. In the crib or log cabin pattern, two logs are set parallel aiming north to south. Another two are placed on them aiming east to west. And so on.
On hillsides too steep for either pattern, there is a hybrid of the two called Japanese hillside stacking. It’s a trickier pattern best learned by doing. Check out a short video from Cornell University Extension that shows this technique.
Potential Pest Problems
Growing shiitake mushrooms is pest-free most of the time, but a few problems might show up. The most likely one comes from competing fungi: They might appear if the logs are resting on the ground.
Scare up some free pallets and spread them as a layer on the ground for your logs to rest on and to create a moat between your logs and fungus in the soil. This also deters termites. Laying your logs under a canopy of conifers also works: Pro-conifer fungi won’t attack deciduous wood.
Sometimes beetle larvae appear in the gills of your brand new mushrooms. You can prevent this by covering the logs with a fine mesh to preclude beetle egg-laying. Quick harvesting of mushrooms while the caps are still concave also prevents this.
When harvesting mushrooms with beetle larvae crawling around inside the gills, some folks have blown them out with a hair dryer.
If snails are a problem, you can trap them with decoys of lettuce or cabbage leaves on the ground. Kill slugs with salt or scoop them up for your chickens. Spreading wood ash can also deter them.
But How Much Money?
Wholesale prices on shiitake mushrooms run $5 to $9 a pound, and your retail price at the farmers market might be twice that. According to the North Carolina Ag Extension Service, a cord of about 125 logs could grow as much as 500 pounds of shiitake per year.
At the low end of the wholesale price you’d make about $2,500.
That cord might cost you about $125 and an equal amount for the spawn. Add another $1,000 give or take for labor and other expenses on that cord (unless helpers are paying you for their CrossFit training).
And then, depending on whether you let the logs fruit naturally or you force them by dunking, and whether you sell wholesale or retail, your annual net might be $500 to $3,700.
Data from the University of Vermont shows that a 500-log stand would net a farmer $6,000 to $11,000 a year, depending on whether the shiitakes were sold wholesale or retail.
Here’s one last bit of advice: Keep a written record of frequency of fruiting, time between dunking and fruiting, prices paid and so on to help you learn the best practices with your logs, market, site, climate and cultivar.
And maintain good quality control by sampling the merchandise on a regular basis.