Shiitake cultivation protocol

This is our “cheat sheet” of reminders for cutting and inoculating shiitake logs at Chert Hollow Farm; it’s not intended as a complete “how-to” manual. We recommend the following references for further information & guidance:

Online

Books

  • Ken Mudge Ken and Steve Gabriel, 2014, Farming the Woods, Chelsea Green Publishing.
  • Paul Przybylowicz  & John Donaghue, 1990, Shiitake Growers Handbook, Kendall/Hunt Publishing Company.
  • Mary Ellen Kozak and Joe Krawczyk, 2008, Growing Shiitake Mushrooms in a Continental Climate, 2nd edition.

Selecting Trees & Cutting Logs

Equipment List for Log Harvest:

  • Roll of flagging
  • Chain saw & associated equipment
  • Ear protection
  • Goggles
  • Loppers
  • Measuring tape
  • Chalk
  • Aluminum tags
  • Staple gun & staples
  • Sharpie
  • Ziplock bags or tupperware to keep log-cut cookies moist
  • Drill
  • Eye bolts (if intending to hang logs for weighing)
  • Scale (for logs)
  • Scale (for cookies)
  • Record sheet & clipboard, pen

Considerations for cutting logs:

  • Cut oaks in the first two weeks of February.
  • Maples can be cut a bit later (but try for February).
  • Try to minimize time between cutting & inoculation (aim for <2-3 weeks).
  • Bark characteristics are an important consideration for tree selection: look for tight bark, not loose & flaky.
  • Log diameter should be approximately 3” – 7”. Too big: gets heavy to handle, can have lots of heartwood, & uses lots of spawn. Too small: prone to drying.
  • Cut logs to length of 4 feet for passive management, shorter for active management.
  • If cutting cookies for Log Moisture Content (LMC) monitoring after transport to barn, then leave an extra half foot or so on prospective reference logs.
  • Be very careful with logs when cutting & moving; do not damage bark. Best logs will have few to no branch scars
  • After cutting but before inoculation: Stack logs off of ground in a firewood-style pile (dead stack). Put a clean tarp over the pile to keep moisture in.

Log Moisture Content Monitoring: Cookie Cutting & Drying; Designation of Reference Logs

Cut fresh “cookies” about 1″ thick from end of reference logs. Keep moist & weigh as soon after cutting as practical. Set oven temperature in the 175-200ºF range. Put “cookies”in oven in the evening & dry overnight. Check weight in the morning, then check approx. hourly until there is no more weight change. Record oven dry weight on record sheet & do LMC calcs (on another worksheet in the same file).

To save on oven use: Measure the initial cookie weight right away, but let air-dry until all logs/cookies are cut, then over-dry all at once.

Ordering Spawn & Supplies

Field & Forest tends to have a quick shipping time, but probably best to order as soon as the needed amount is known; allow a couple of weeks ideally in case preferred spawn is out of stock. Spawn can be stored in the refrigerator if needed. Before ordering spawn, also check other supplies: wax, daubers, aluminum tags.

Inoculation of Logs

Supply list for inoculation day:

  • Saw horses (~5 or 6)
  • Cedar rails
  • Loppers/pruners
  • High-speed drill
  • Drill bit Measuring stick (6” marks)
  • Inoculation plunger
  • Repair kit for inoculator w/ extra spring & screw
  • Sawdust spawn (of course)
  • Lidded container to hold spawn
  • Fire extinguisher, charged & accessible
  • Wax-melting set-up:
    • Camp stove
    • Concrete blocks
    • Grill grate
    • Fuel—plus extra
    • Matches
    • Wax pan
    • Cheese wax
    • Candy thermometer & spare
    • Wax daubers
    • Bucket of cold water for minor burns
  • Aluminum tags
  • Pen
  • Staple gun & staples
  • Record sheet/clipboard
  • Ear protection
  • Stools
  • Snacks/water; have a pre-made quick lunch to minimize time cooling/reheating wax

Pick a day with a high above 40ºF for the actual inoculation. In 2011 we inoculated with a high in the 30s & had wax-cracking issues; I think the temperature might be to blame. A humid day is better than a very dry/windy day. But inoculating quickly after cutting is probably of even higher importance. Inoculation of 8-10 logs/hour for two people is possible once everything is set up and working properly.

Drilling

Drill in a diamond pattern: 6” between holes within a row, ~1.5” between rows. Drill extra holes near branch scars or other problematic areas. Pay attention to the color of the wood coming out from around the bit. It should be yellow to off-white. Darker color/off-smell indicates dead wood & should be discarded for firewood (See Kozak & Krawczyk, p.29).

Inoculation

Open the bag carefully if the spawn won’t all be used in one session: Cut at the top and leave the breathable patch intact. Put the bag in a container with a lid and put the lid on anytime the spawn is not in active use. When a drilled log is ready, plunge the inoculator into the spawn several times to fill. Then deposit the spawn in the hole. Reach for more spawn with the inoculator hand, and use a finger of the other hand to press the spawn all the way into the hole. The hole should be fully packed but not mounded. Repeat. On occasion, check the screw in the inoculator to make sure it isn’t about to fall out. Losing the screw in the spawn can be a real problem, especially if there’s no backup on hand.

Sealing with Wax

While making breakfast, start the wax melting on the stovetop indoors to get a start on this slow process and to save on camp-stove fuel. Warning: Do NOT heat the wax above 400ºF. The flash point is 450ºF (Kozak & Krawczyk, p.33). If there are black or blue wisps, it has gone too far; grab the fire extinguisher. If using the gas stove: Use concrete blocks to make a stable place for a grill grate to hold the pan of wax. Put the camp stove under the grill.

Monitor the temperature with a metal candy thermometer. Wax should be 350ºF to 400ºF. With the daubers, 375ºF seems to perform much better than 350ºF. There should be a nice sizzle on contact and the wax should spread to a thin film. Cooler temperatures tend to lead to more globs. Rotating the log so that the holes to be waxed are on the upper surface will help to reduce drips.

Labeling

Write the following on an aluminum tag with a pen:

  • date of inoculation
  • the spawn strain
  • the tree species

Use the staple gun to attach the labels to the logs. Record information about the logs on the record sheet for inoculation day.

Stacking

Stack logs to maximize exposure to rainfall, to minimize drying, and to minimize contact with the ground. Scraps of cedar lumber are good for keeping inoculated logs out of contact with ground.

Monitoring Log Moisture Content

Create a cheat sheet that tells the weight of each reference log at the critical LMCs; see the ReferenceLogCalcs worksheet of the Excel file linked above.  Periodically over the course of the first year, weigh the reference logs to see how they’re doing. In case of extreme drought, use a misting system to keep logs moist.