Manual: Shiitake Donko Spawn

Shiitake Donko - Spawn

(Lentinula edodes)

Use the spawn as soon as possible after you receive it, or keep it in the fridge for a few weeks at most.

Donko is a cold weather strain. It grows slowly, but gives thick, short stemmed and dark brown caps. You can use this spawn in two ways: on a substrate block indoors, or on fresh hardwood logs outdoors.

What you need:

  • Shiitake Donko spawn
  • Substrate: hardwood sawdust with bran, or a fresh oak or beech log
  • A pressure cooker or another way to sterilise
  • A grow bag with a filter, or a clean container
  • A clean working area, gloves and alcohol

Preparing the substrate:

Mix about 80 percent hardwood sawdust with 10 percent grain and 10 percent bran. Add water until the substrate just releases moisture when you squeeze it, without being soaked. Sterilise it for 2 hours at 15 PSI in a pressure cooker and let it cool down completely.

Inoculation:

Work in a clean area, disinfect your work surface and wear gloves. Mix the spawn evenly through the cooled substrate, roughly 1 part spawn to 10 parts substrate. Close the grow bag with a filter or micropore tape.

Incubation and ripening:

Keep the bag in the dark at around 23 degrees. After two to three weeks the substrate is white throughout, but you are not there yet. Shiitake then needs a ripening phase in which the block turns brown and forms a leathery skin. On sawdust blocks that takes a while: expect several months. Simply leave the block in the closed bag during that time.

Growth and fruiting:

Once the block is brown, take it out of the bag. Submerge it in cold water for 12 to 24 hours; that cold shock triggers fruiting. Then put the block somewhere with a high humidity, around 85 percent, and a temperature between 14 and 17 degrees. At that low temperature donko forms its thickest caps. Give it daylight and fresh air.

On a log:

If you want to use the spawn on wood, drill 10 mm holes in a fresh oak or beech log, fill them with spawn and seal them with wax. Donko grows largest on wood, but it takes a year or more before the first harvest.

Harvesting:

Harvest when the cap has opened about three quarters of the way and the rim still curls inward. Cut or twist the mushroom off at the base.

Storing:

Keep the harvested shiitake in a paper bag in the fridge. They last a good week there and dry excellently.

Second harvest:

Expect 3 to 5 flushes, 14 to 16 days apart. Let the block rest in between, and submerge it in cold water again if nothing happens.

Cleaning up:

Once the block is exhausted you can compost it or use it as a soil improver in the garden.