How to Prepare Growing Medium for Mushrooms

Find a source for clean wheat straw. It should be baled and have no seed heads. Livestock feed stores are a good source.

Open the binding on the bale of straw and remove one flake at a time. Wheat straw is baled to separate into ‰??flakes' for easy distribution.

Chop or shred the wheat straw into 1 - 3 inch pieces. Sterilized garden shears can be used for this step, or a butcher's cleaver. Make sure the surface you are working on has been sterilized with a 10% bleach solution.

Place the prepared wheat straw into clean, cotton pillow cases.

Soak the straw-filled pillow cases in hot water for 1 hour.

Remove the straw-filled bags from the hot water bath and allow to drain in a clean sink for several hours.

Remove the damp straw from the pillow cases and transfer to clean, clear plastic bags.

Add soil amendments (optional). 1/4 c. rice bran and 1 tbsp. of calcium carbonate (limestone) can be added to damp straw at this point.

Add mushroom spawn (purchased from a reputable supplier) to the straw-filled plastic bags. Close the bag and shake vigorously to incorporate the spawn throughout the growing medium.

Pack the straw into the bags as tightly as possible to create a brick, or block. Once the block has been formed, seal the bag tightly.

Puncture the plastic bag 25 - 50 times with a sterilized nail to allow air to penetrate. The nail should be sterilized with the bleach solution between puncturing each individual block.