man scooping up dried horse manure from tubs

Manure Based Mushroom Substrate Recipe

Manure-Based Mushroom Substrate Recipe: Perfect for Portabella and Other Agaricus Species

Manure-based substrates are ideal for growing a variety of dung-loving mushrooms. This recipe provides a nutrient-rich environment that these mushrooms thrive in. In this guide, we'll walk you through preparing the perfect manure-based substrate for your mushroom cultivation needs.

Ingredients for Manure-Based Mushroom Substrate

For a standard batch (adjust quantities as needed):

  • 8 quarts horse manure (dry, sun-bleached, and powdered)
  • 4 quarts coco coir
  • 4 quarts vermiculite
  • 0.5 quarts gypsum

This recipe follows a 2:1:1 ratio of manure to coir to vermiculite, with about 5-10% gypsum by volume.

Equipment Needed

  • Large mixing tub
  • Drill with paddle mixer attachment
  • Measuring buckets or containers
  • Large autoclavable bags (21x10 inches with 5-inch gusset)
  • Pressure cooker or large pot for pasteurization
  • Thermometer
  • Personal protective equipment (gloves, mask, and safety glasses)

Step-by-Step Substrate Preparation

1. Prepare Your Workspace

  1. Set up your large mixing tub in a clean area.
  2. Secure the tub to the ground with blocks to prevent movement during mixing.

2. Prepare the Ingredients

  1. Break up and soak the coco coir brick until it becomes light and fluffy.
  2. Ensure the horse manure is dry, sun-bleached, and broken into a fine powder.

3. Mix Dry Ingredients

  1. Add 8 quarts of horse manure to the tub.
  2. Add 4 quarts of prepared coco coir.
  3. Add 4 quarts of vermiculite.
  4. Add 0.5 quarts of gypsum.
  5. Use the drill with paddle mixer to thoroughly combine all dry ingredients.

4. Hydrate the Substrate

  1. Boil water to use for hydration. Hot water helps bring the substrate to proper temperature more quickly.
  2. Gradually add hot water to the dry mixture, stirring constantly.
  3. Aim for "field capacity" – when squeezed, only a few drops of water should come out of a handful of substrate.

5. Bag the Substrate

  1. Once at field capacity, pack the substrate into large autoclavable bags.
  2. Fill each bag up to just below the filter patch.

6. Pasteurize the Substrate

  1. Place filled bags in a pressure cooker or large pot with water.
  2. Heat the water until the internal temperature of the substrate reaches 140-180°F (60-82°C).
  3. Maintain this temperature range for 1-3 hours to ensure proper pasteurization.
  4. Monitor the temperature carefully to avoid overheating, which can kill beneficial microbes.

Tips for Success

  • Use sun-bleached horse manure for best results. Fresh manure can be too "hot" and may contain harmful bacteria.
  • The vermiculite helps with moisture retention, while gypsum aids in pH balance and provides essential minerals.
  • Always practice proper hygiene and use protective equipment when handling manure-based substrates.
  • Be patient during the pasteurization process – maintaining the correct temperature range is crucial for success.

Conclusion

This manure-based substrate recipe provides an excellent growing medium for portabella, white button, cremini, and other Agaricus species mushrooms. By following these steps, you'll create a nutrient-rich environment that promotes healthy mushroom growth.

Remember, the key to success lies in maintaining proper ratios, achieving the right moisture content, and ensuring thorough pasteurization. With practice, you'll be able to consistently produce high-quality substrate for your mushroom cultivation projects.

Happy growing, and may your harvests be bountiful!

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