Shii-take on pasteurized coco blocks

This page explains another technique for inoculating a substrate, this time a Shiitake Mushroom spawn on a coco block substrate. It should be understood, however, that there are many different techniques and that any technique respecting the basics of mushroom growing will give you a good result. You may have to use another substrate than coco blocks, for example; this is ok, as long as it has similar characteristics to coco blocks.


  • 3 coco bricks, or 2 kg of coco- fibres
  • a 2 liter (1,4 kg)- portion of spawn
  • 1 large Microsac (bag with in-built filtering system)
  • a pair of disposable gloves
  • adhesive tape
  • a long pin


preparing the coco substrate through pasteurization

shaking the shiitake coco substrate


  • Put on disposable gloves before unwrapping the coco-blocks
  • Put 3 blocks side by side (or fill 2 kg of loose coco-fibres) in a Microsac
  • Pour 6 litres of boiling (!) water over the blocks
  • Fold up the Microsac in order to prohibit any air-borne microorganisms to land on the substrate. Make sure the bag does not unfold.
  • Let soak for 6 - 8 h, till the temperature has sunk below 25°C, and the blocks have entirely absorbed the water
  • Loosen up the fibres without opening the bag, in order to aerate the substrate.
  • If you can get to some CaCO3 (chalk), mix in 0.5-1% to rise pH a little.

inoculation of shii-take substrate

shaking the inoculated bag


  • Crumble the spawn inside its original packaging. Open both Microsac and spawn-bag, and scatter the spawn over the surface of the substrate. Do this quickly, without getting dirty hands or tools inside the bag.
  • Seal up the Microsac (e.g. with adhesive tape), and mix thoroughly spawn and substrate.
  • For your information: Shiitake spawn on pasteurized substrate should be mixed in at about 10%.

shii-take substrate ripening phase

primordia formation in shii-take substrate


  • Place the bag in a room with a temperature of 15 - 20 °C. After ± 14 days, the mushroom mycelium will have turned the substrate completely white.
  • Prick, by means of a long pin (e.g. knitting needle), 50 deep holes through the bag and into the centre of the substrate block.
  • Leave the bag in the same room till, after ± 14 days, sometimes a little longer, mushroom primordia with a diameter of ± 1 cm should have formed under the plastic.

fructification of shii-take mushroom substrate


  • Tilt the substrate block inside the closed bag. This will create enough space between plastic and substrate to allow the mushrooms to develop.

harvesting the shii-take mushrooms


  • Cut the actual top (= former side) of the bag, remove the mushrooms entirely, and sprinkle the substrate before resealing the Microsac.
  • Keep the block at 15 - 20 °C; and after a few weeks -sometimes longer - a second series of primordia will form, which will grow into firm mushrooms.
  • Remove the plastic, harvest the mushrooms, and place the block in a shady corner of the garden. In every spell of damp weather, you may harvest a few mushrooms, till depletion of the substrate.