It looks like many of us here in Connecticut are having a “White Christmas”! Enough snow fell the morning of the 24th to require shoveling. With freezing rain in the forecast for Christmas Day however, most people will probably choose to spend the day indoors, ideally by the fire with a warm drink and a book. While I didn’t have a yule log burning, this year I tried my hand at preparing some mushroom cultivation logs between other holiday festivities.

The idea to try growing mushrooms at home came to me earlier in the year when I wanted to buy some shiitake mushrooms for a recipe I was making. I was able to get them from a supermarket nearby and found that they had been grown here in New England. I was delighted to know that the mushrooms had been grown nearby and wanted to take a shot at growing them myself. With a little research, I found I had most of the tools I needed already at home.

Unlike oyster mushrooms and some other types that are easily grown in compost substrate, shiitake are more easily grown using hardwood logs. When selecting a log, choose one that is solid and freshly-cut, with no symptoms of disease. An ideal choice would be an oak or maple log, 2 to 4 feet long and 4 to 8 inches in diameter. Fortuitously, I did not need to purchase any such logs this year as a neighbor removed a few branches from a healthy oak that had been overhanging the street and was happy to share.

The “perfect log” was a fortuitous gift from a neighbor dealing with yard waste. It is about 20in long with a 5in diameter.

Once the proper logs have been collected and cleaned, they are ready to be inoculated with shiitake “spawn”. This refers to the shiitake mycelium – the threadlike “body” of the fungus that produces mushrooms after sufficiently colonizing the log. Many hobbyists sell this spawn growing on hardwood sawdust or on hardwood dowels. I chose to use dowels to inoculate my logs, which I purchased from a reputable online vendor.

I drilled holes barely larger than the inoculation dowels at regular intervals across the log. Since this was my first time, I used plenty of inoculation dowels to increase the likelihood of the mycelium rapidly and uniformly colonizing the log. I placed each inoculation dowel over the hole and gently hammered it in place using a rubber mallet. When hammering the dowels, I realized that some of the holes I drilled were a little too narrow and the dowel would not completely fit.

I drilled the holes in my garage to keep my workspace tidy. The holes were just barely larger than the inoculation dowels I was planning to use. A clean dowel without mushroom spawn is placed near the log for illustrative purposes.

Conversely, a few of the holes I drilled were too large and there were some small gaps around the dowels. These gaps create easy entry points for other fungi to enter the log and compete with the shiitake for resources, so it is important to seal them. I used melted beeswax to cover the holes. Although I just poured the beeswax over the holes with success, this was a somewhat messy process. I reviewed some tips online and found that many people use a horsehair paintbrush to “paint” the melted wax over the holes. I will probably do the same moving forward for easier cleanup and a nicer appearance. I recommend using a brush if you plan to gift the mushroom log to a loved one.

Holes that are too large for just the dowel need to be sealed to prevent other fungi from colonizing the log. An example of such a hole is shown here.
I used white beeswax pellets to fill the gaps around the dowels. Other non-toxic sealants and waxes may also be used, such as paraffin wax, but beeswax is what most hobbyists use. The beeswax I chose to use was not cosmetic-grade, so it was affordable and easy to find.

When the dowels are finished, label and date the log. I chose to use a permanent marker to label the cut end of the log, but some people prefer to attach labeled tags to the logs. Many hobbyists online recommend coating the cut ends of the log in wax to reduce the likelihood of other fungi colonizing the log. This seems to be especially recommended for people keeping the logs in warm, humid environments with lots of fungal pressure, such as in the Mid-Atlantic and Southeastern states. I did not coat the ends of my log initially, but I may choose to do so before moving them outside in the spring.

My labeled log is all ready to go! I used permanent marker to ensure that the label will not wash off when the log gets wet. Covering the end with beeswax would help the log retain moisture, protect it from other fungi, and have the added benefit of protecting the label from being damaged or discolored.

It is important to protect the shiitake logs from freezing temperatures while they are initially being colonized. For this reason, my logs will be spending the winter in my garage. They need to be kept moist, so I will water and turn them once each week when I water my other houseplants. The bark should dry out completely between watering.

When there is no longer a risk of freezing temperatures, I will move the logs to a shady area in my yard. The logs will not need to be covered unless there is a risk of them drying-out (e.g., intense heat wave) or if there is a severe storm that could flood or damage the logs. After the logs produce their first “batch” of mushrooms, they should be considered fully colonized and will not need to be protected from the cold. With a little luck, the logs will produce mushrooms once or twice each year for about 5 years.  

I’ll report back next year on the success of my efforts and any additional tips or trick I pick up in the process.

Happy holidays!

Nick