RUMFORD — About a dozen people from the Andover-Bethel area learned how to grow shiitake mushrooms Saturday at Toshio Hashimoto’s Shiitake Farm greenhouse.

Hashimoto, 65, has been growing shiitakes for more than 40 years, mostly after moving his family to Rumford from Boston in 1985. He also conducts shiitake growing workshops worldwide.

He elicited laughter from participants when he recommended that they follow his advice, which is based on his experience growing shiitakes, rather than getting advice from books.

While holding a red oak log outside his greenhouse, Hashimoto said hardwood trees are best when it comes to growing shiitake mushrooms.

“The best wood to use is white oak, but I couldn’t get the white oak so I am using the red oak,” he said, answering a participant’s question. “Because red oak has a lot of oil, so the mycelium, it is very hard to get in deep.”

Mycelium is the vegetative mass of filaments of fungi. The mushroom only grows from the hole drilled into the wood and, so far, Hashimoto said he doesn’t see much difference between growing shiitakes in red oak or white oak. 

He said he has used birch and ash logs to grow shiitakes but advised against using poplar because, he said, there is no nutrition in poplar. Almost any deciduous wood can be used if it keeps its bark for several years. The bark is key to growing shiitakes.

“Don’t drag logs,” Hashimoto said. “If the bark peels off, forget it.”

The first step is to cut the log over the winter or in early spring when the snow is gone, but before the leaves come out, he said.

After he cuts a log, he waits 20 days before slicing it.

“If you have a lot of water in your trunk, mycelium doesn’t grow very good,” Hashimoto said. “Mycelium needs water and oxygen.”

Using a drill and a special drill bit from Japan that comes with each shiitake kit he sells, he drilled a series of holes ¾ of an inch deep and about three inches apart in staggered rows.

He took a plastic milk container in which he had stored his own blend of shiitake spores in sawdust, cut it in half, and passed around one cross-section so participants could smell the odor of healthy spawn. They resembled roughly circular, small white dots.

“Remember that smell,” Hashimoto said.

“The white stuff is what you want,” participant and shiitake grower Conni St. Pierre of Bethel said.

Using a Japanese fountain pen-like device called a planter that is also included in his kits, Hashimoto tamped the open end of it a few times in a plastic bin containing the spawn mixture. He positioned the open end over the drilled hole and plunged the cap down, neatly depositing the spores and sawdust in the hole.

Hashimoto then took a column of Styrofoam caps from the kit, peeled off one at a time and capped the inoculations. The rest of the work involves spacing out and stacking the logs above the ground in a cool, shaded place and covering them with a tarp. If it gets warm, he said to sprinkle the logs with water.

Inside his large greenhouse, Hashimoto lifted tarps to show previously inoculated logs at various stages of incubation. On the other side, many logs stood on end under blue tarps that when lifted revealed many growing shiitake caps of various sizes.

Afterward, St. Pierre and participants Linda McDonough of Bethel and Carol Emery of Andover said they enjoyed learning the art and science of growing shiitakes.

“I loved it,” McDonough said. “He is extraordinary and such a wonderful person.”

“It’s really flavor-able,” St. Pierre said of a shiitake mushroom. “I find it more flavor-able than the portobellos.”

She said she and her husband eat shiitake bacon and use the recipe found here: www.thedeliciouslife.com/how-to-make-shiitake-bacon. “We love it.”

tkarkos@sunmediagroup.net