mixing GIY substrate - Grow.bio

How to incorporate new substrate into your GIY material

Curious about working with other substrates in your GIY mycelium material? Try changing the recipe to create different end-results, such as strength, performance, acoustics, and flame retardation. 


Why add another substrate to your GIY material?

  • Changes the properties of the material and therefore the application.
  • Use local waste stocks that you have on hand
  • Test to see what mycelium will grow on (almost anything!)
  • Grow out your material to maintain your own supply at home. 
    • Like a sour dough starter, you can divide your GIY material once in Step 2 and add in new substrate. Let it grow out for a week and repeat.

Examples of substrates to incorporate into GIY material:

  • Coffee grounds
  • Paper pet bedding
  • Aspen pet bedding
  • Yarn or shredded fabric
  • Coconut husks
  • Hardwood shavings

How to incorporate another substrate into GIY material:

  1. First, you must pasteurize the substrate you would like to add to the GIY material. Follow the home pasteurization instructions in our blog post "How to pasteurize substrate at home" to prepare your substrate.

  2. Sanitize your work surface, gloves, tools, and mixing bowl using 70% rubbing alcohol in a spray bottle, allowing it to evaporate.

  3. Reserve 30% of the existing GIY material and introduce 70% of the freshly pasteurized substrate into the mix, along with 3 tablespoons of flour as nutrition.

  4. Seal the material in a clean container to both retain moisture and allow air exchange. Mycelium needs high humidity to grow but also respires CO2. A good choice is sealing a glass bowl with plastic wrap and poking a few holes, or using a filter patch bag, a standard for mushroom cultivation. 

  5. Allow the mycelium to recolonize the material, allowing it to grow for 4-6 days until the material turns white again. Note: Maintain a room temperature of around 72° F for optimal mycelium growth; colder temperatures will slow down the growth process.

  6. Once the material is grown throughout the new substrate mix, either add the material to a growth form and let it grow to the form’s shape for 5-6 days. You also have the option to complete another division step using the same ratio, 30% of the original material with 70% of the new substrate, and added flour. 

  7. Repeat these steps in order to create a continuous supply of mycelium material.


Visit Grow.bio’s store to order GIY material and get growing! If you want to learn more, follow us on Instagram and Tiktok @grow.bio for how-to’s, myths, and tips and tricks with GIY mycelium material!