Sawdust block
King oyster on a sawdust block
Pleurotus eryngii
- Difficulty
- Some practice
- First harvest
- 5 to 8 weeks
- Keeps producing
- Usually one good flush, occasionally two
- Substrate
- Hardwood sawdust supplemented with wheat bran, sterilised in a filter-patch bag
Conditions that actually matter
Colonise in the dark at 22 to 25C, fruit at 15 to 18C with low light and restricted fresh air, which is what makes the stems long and thick.
The method
- 01Sterilise the substrate in a pressure cooker at 15 psi for two and a half hours. Boiling water will not do it: bacterial spores survive 100C.
- 02Cool completely, then inoculate with grain spawn in front of a still air box or flow hood.
- 03Colonise in the dark for three to five weeks until the block is solid white.
- 04Cut a single small opening and drop the temperature. Restricting fresh air at this stage encourages the thick stems the species is grown for.
- 05Harvest before the caps flatten out.
What decides whether this works
Sterile technique at inoculation, and a genuine pressure cooker. This is the step where hobby cultivation gets real, and contamination at inoculation is the single reason most first attempts fail.
What you need for this method
What this step needsPressure canner$184.99
What this step needsStill air box and sterile supplies$35.99
What this step needsPlug spawn and grain spawn$21.99
What this step needsFilter patch grow bags$24.99Some links here are Amazon affiliate links. If you buy through one we earn a commission at no extra cost to you, and it never changes what we recommend. Prices were read from Amazon when this page was built and will have moved since.
A sterilised block you colonise yourself from spawn. The step where sterile technique starts to matter, and where most first failures happen.
The species, in the wild
Choice
King oyster
A thick white solid stem with a small cap. In cultivation it is the meatiest mushroom available.
Other methods