Innovative Growing Medium for Gourmet Mushrooms: Regenerative Substrate Solutions

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As a small business dedicated to sustainable agriculture, we took the decision seriously to continue opting for regenerative byproducts as our substrate for growing mushrooms.

Using sawdust from the local sawmill on the island was no longer an option, as there simply wasn’t enough available to meet the scale required for our cultivation. Faced with this challenge, we began researching alternative substrates that aligned with our values and local resources.

That research led us to an unconventional idea: using macadamia nut shells and husks, along with coffee parchment from a local coffee mill. It was a leap of faith. After combing the internet for any references to growing mushrooms on macadamia byproducts—and finding none—we knew we were stepping into uncharted territory.

We continued researching how mycelium breaks down tough lignin structures in materials like bark and sawdust, and began to see parallels with macadamia shells and husks. With over 5,000 acres of macadamia nut orchards on the island, we also knew that supply would be abundant and long-term.

So we went for it.

We invested in a small hammer mill to reduce the particle size of the macadamia byproducts and dial in appropriate substrate ratios. After several months of experimentation, we perfected a recipe incorporating macadamia husk, coffee parchment, and a small amount of rice bran to boost yields.

Thus began a new era in our mushroom farming journey.

By using macadamia byproducts, we continue our mission of cultivating high-quality mushrooms on Hawaiʻi Island while relying on regenerative materials sourced from local agriculture. We are constantly refining our substrate recipes based on the specific mushrooms we’re growing, and by transforming these byproducts into rich, living substrates, we create a closed-loop system that supports sustainability, reduces waste, and nourishes our community.

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Julie Feliciano

Co-Owner

Volcano Mushrooms LLC