Straw & Wood Pellet Mushroom Substrate Recipe

Creating a substrate for growing oyster mushrooms involves a mix of organic materials that provide nutrients and support for mushroom growth. Here's a basic recipe for making a straw and oak pellet mushroom substrate for oyster mushrooms:


  • Wheat Straw:
    • 5 parts chopped or shredded wheat straw (available at feed stores or online)
  • Oak Pellets:
    • 3 parts oak pellets (usually used for pellet stoves, available at pet stores or online)
  • Water:
    • Sufficient water to hydrate the substrate
  • Gypsum (optional):
    • 1/2 cup gypsum (helps with water retention and provides additional nutrients)


  • Large container or bucket:For mixing the substrate ingredients.
  • Large bag or pillowcase:For pasteurizing the substrate.
  • Thermometer:To monitor the pasteurization temperature.
  • Pressure Cooker (optional):For sterilizing the substrate.


1. Preparing the Wheat Straw:

  • Chop or shred the wheat straw into smaller pieces to facilitate even mixing.

2. Hydrating the Substrate:

  • Place the chopped straw in a large container or bucket.
  • Add the oak pellets to the container.
  • Gradually add water while mixing until the substrate is evenly moist. Aim for field capacity, where the substrate holds together when squeezed but does not release excess water.

3. Pasteurization:

  • Transfer the substrate to a large bag or pillowcase.
  • Heat the substrate to pasteurization temperature, ideally between 140°F to 160°F (60°C to 71°C). Hold this temperature for at least 1 to 2 hours to kill competing organisms. Use a thermometer to monitor the temperature.

4. Cooling:

  • Allow the substrate to cool to room temperature.

5. Gypsum Addition (Optional):

  • If using gypsum, mix it into the substrate during the cooling phase.

6. Filling Bags or Containers:

  • Once the substrate is cool, fill mushroom bags or containers with the substrate. Leave some room at the top for the mycelium to colonize.

7. Inoculation:

  • Inoculate the substrate with mushroom spawn. Distribute the spawn evenly throughout the substrate.

8. Incubation:

  • Place the inoculated bags or containers in a warm and dark environment for the mycelium to colonize the substrate. This incubation period typically takes a few weeks.

9. Fruiting:

  • Once the substrate is fully colonized with mycelium, introduce fresh air and light to initiate the fruiting stage.

Note: This is a basic recipe, and mushroom cultivation can be nuanced. Sterilization may be necessary in some cases, and specific oyster mushroom species may have slightly different requirements. Always follow best practices for cleanliness and consider consulting more detailed guides or experts in mushroom cultivation for specific varieties.

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