VANCOUVER, Wash. — As a regional agriculture specialist for Washington State University Extension, Justin O’Dea focuses on helping farms near larger cities find their niche growing novel specialty crops for local markets.

His latest project is the first of its kind in the Pacific Northwest, teaching farmers how to grow shiitake mushrooms outdoors.

The umami delicacy, native to East Asia, is commonly produced in Japan and has gained a foothold in the northeastern U.S. O’Dea is now studying the best methods for cultivating shiitake on forest logs in western Washington and Oregon.

O’Dea said he was first exposed to log-grown shiitake years ago while working on a small family farm near Apalachin, N.Y.

“The thing that stood out to me is it was just really different,” he said. “It is a way to produce food out of a forest resource.”

Mentorship

Japan honed the log-grown method of growing shiitakes in the 1940s, O’Dea said.

The basic concept is simple — logs are inoculated with mycelium, the stringy, root-like structure of a fungus, which then feeds on the dead wood and eventually forms into mushrooms. But there are still plenty of unanswered questions, including which types of wood and which strains of shiitake will perform best in the region.

The climate of the Northwest poses another challenge, O’Dea said, with its hot and dry summers compared Japan and the Northeast where it tends to be rainier and more humid.

“It’s almost reliably dry (here) from July to September, except on the coast,” he said. “That was the second main component of our original trials, trying to find a way that was cheap and simple to keep the log viable, especially during the first year.”

Research trials began in 2019, and offered enough potential for the USDA’s Western Sustainable Agriculture Research and Education program to award a three-year, $175,000 grant allowing O’Dea to expand his work.

O’Dea has also partnered with WSU Extension forester Patrick Shults and Oregon State University researcher Eric Jones to mentor a dozen farmers interested in diversifying their operations by adding log-grown shiitakes.

“These new Northwest shiitake farmers will eventually be able to provide that mentorship to future growers,” O’Dea said.

Initial findings

So far, O’Dea said, Garry oak and red alder have performed the best in his shiitake experiments at the 78th Street Heritage Farm near Vancouver, Wash.

It takes about 15 minutes per log to drill holes and introduce the mixture of mycelium and sawdust, known as “spawn.” From there, it takes about 12-18 months for the shiitake mushrooms to appear, depending on the wood species.

In the meantime, O’Dea has experimented with two strategies for keeping logs from drying out too much during the summer.

The first is to stack logs after they are inoculated and use a cover to retain moisture in the log that would otherwise be lost to sun and wind. The second is to soak the logs for 24 hours in metal stock water tanks, giving them a “recharge” of wetness.

O’Dea said the research team continues to add different wood species and mycelium to their trials to see which give aspiring shiitake growers the most bang for their buck.

“I hope we can figure out a wider array of tree species we can use for the production substrate,” he said. “We have a lot in the trial now.”

Low barrier to entry

O’Dea said he believes Northwest farmers can make money growing and selling log-grown shiitake, though he cautions it is not intended to be a cash cow.

“It’s a system that works well with smaller to moderate scale farms,” he said. “It’s not a system that you can really scale up way big.”

Growing shiitakes indoors might increase yields, O’Dea said, by creating ideal environmental conditions for the mushrooms. However, building a facility and investing in that equipment is much more expensive than the log-grown method.

“This forest-cultivated system has really low barriers to entry, economically,” he said.

O’Dea estimated that fresh shiitake mushrooms could sell for up to $20 per pound, although that depends heavily on markets. Shiitakes can be used by chefs in a variety of Asian noodle dishes, stews, pasta sauces and stir-fry.

“I’d say they have a texture and taste that’s not going to offend people,” he said. “It’s not slimy, it’s not crunchy, it doesn’t have a strong flavor. It just has a wider array of uses.”

Shults, the WSU Extension forester, said the team is excited to support Northwest shiitake growers through their mentorship program, giving them something unique to help them stand out among consumers.

“From our travels, we know we’re headed in the right direction,” Shults said.

Justin O’Dea

Age: 45.

Occupation: Regional agriculture specialist, Washington State University Extension.

Hometown: Camas, Wash.

Education: Master’s degree in land resources and environmental sciences, Montana State University.

Family: Wife, Lisa Bullard, and two children, ages 7 and 12.