Growing Shiitake Mushrooms

comments (0) November 18th, 2009

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My husband and I grow shiitake mushrooms at home, using logs cut from trees on our place. This fall, we had a two-day shiitake mushroom workshop at our place at the request of my garden club We had 18 people, including some from the garden club plus some of our neighbors. We all shared the cost of the materials and the work, and each person or couple took a few logs home at the end.

	A downed sapling is being measured in 4-foot sections by Adrian (on left) while Don comes behind him to make the cuts with his chainsaw.
	The stacks of cut logs are ready for innoculation.

This workshop was held on two consecutive Saturdays. The first Saturday about half the group came, and used chainsaws to cut the saplings at our place that we had pre-marked for the purpose. The best trees to use are sugar maple and oak, but you can also use ironwood and hophornbeam. You can't use conifers, ash, willow or black walnut, because the shiitake grow poorly on those types of wood. The oak logs should last five or more years, and the softer ones like hophornbeam may only produce for two to three years.

There are two ideal times to cut the logs: just after leaf drop in the fall, and the days just before the trees begin to bud in the early spring. The trees have the most "energy" in the wood at those times. The ideal shiitake log is 3 to 8 inches in diameter and 4 feet long. Depending on the size of the tree, you may get three to five logs from each tree. The group cut 180 logs and hauled them to our barnyard, where they sat in neat stacks for the week. We had a cold rainy week so there was little risk that the logs would dry out. Otherwise we would have moved them into the shade and covered them.

The second Saturday, the logs were inoculated with the spawn. To grow shiitakes, you buy shiitake mushroom spawn via mail order. The spawn must be packed into 7/16-inch holes that you drill all over each log. The holes are in a diamond pattern and 6 to 8 inches apart.

You can buy dowels or plugs that contain the spawn, but it’s much cheaper if you buy it in bulk and use a special inoculator tool that the supplier sells to pack it into the holes yourself. Then, you have to seal the holes with either cheese wax or a 50-50 mixture of melted paraffin and beeswax.

Each of the four drilling stations (above) had a pair of workers. At right, our tallest and shortest workers team up to drill holes in a log.

We had an assembly line, with four people drilling all the holes in each log along with a helper at each drill station holding the log in place. Another three people packed the holes with the spawn. Several others then uses brushes to paint the holes on each log with the melted wax. We used an old lead melting pot (originally intended for bullet casting) to keep the wax melted but not too hot.

Drilled logs (above) await their turn at an inoculation station. At right, shiitake mushroom spawn is packed into a hole.

	At the waxing station, the spawn is sealed in. A container of melted wax is seen at the center of the photo.

Wax is very flammable, so it needs to be melted in something with a precise temperature control. A temperature of 350° to 400°F is ideal. For example, a hot plate would be risky since it doesn't have as fine a control over the temperature. If the wax starts to smoke, get it off the heat immediately.

Each finished log got an aluminum label attached to one end, which included information on what species of tree was used, which variety of spawn and the date. The finished logs were stacked outside in the shade of the barn. At the end of the day, we took a group photo and then loaded up everyone with their own shiitake logs. The first fruiting of mushrooms should occur next spring if the log colonization is successful.

The work is finished, and the group takes a break. The "lean-to" arrangement of logs in the foreground illustrates the best way to store them in our northern climate.

The logs should be stored in a cool shaded area with high humidity. Moisture content of the logs must remain above 30% for successful spread of the mushroom spawn thru the logs. Log stacking arrangements differ depending on your climate. Here in the north the best stacking is a "lean-to" arrangement. See a good shiitake growing reference for more details on all this.

More info on growing shiitake mushrooms...

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posted in: mushrooms

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