Project Overview
Commodities
- Agronomic: hemp
- Miscellaneous: mushrooms
Practices
- Education and Training: farmer to farmer
- Farm Business Management: cooperatives, value added
Summary:
The rapid expansion of hemp and recreational cannabis production in the Pacific Northwest has generated large volumes of agricultural byproduct, most notably hemp stalks, that are currently underutilized and often composted or burned. At the same time, mushroom growers in the region rely heavily on imported hardwood sawdust pellets as their primary substrate, creating economic and logistical barriers for small-scale and rural producers. This project explored whether whole, chipped hemp stalks could serve as a viable, economical, and sustainable alternative substrate for gourmet mushroom cultivation.
The study evaluated the performance of hemp stalks compared to oak hardwood sawdust pellets, the current industry standard. Two commercially important mushroom species were tested: Pleurotus ostreatus (blue oyster) and Hericium erinaceus (lion’s mane). Four treatment groups were established: supplemented hemp, supplemented sawdust, non-supplemented hemp, and non-supplemented sawdust, with twenty 3-lb grow bags per group. A second trial evaluated lion’s mane on non-supplemented hemp and sawdust substrates.
Results demonstrated that hemp-based substrates supported significantly faster colonization than sawdust across both species and produced equal or higher yields. Notably, non-supplemented hemp performed as well as or better than supplemented sawdust, indicating that costly supplementation may not be necessary when using hemp stalks. Hemp substrates also reduced input costs and reliance on imported materials.
These findings provide growers with a practical, farm-scale pathway to integrate locally available agricultural residues into mushroom production systems without sacrificing yield or consistency. By demonstrating that whole, chipped hemp stalks can perform as well as or better than conventional substrates under realistic conditions, this project offers a scalable model for reducing costs, increasing resilience, and strengthening regional agricultural linkages.
Project objectives:
Research Objectives
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Determine first-flush yield (g) of blue oyster (Pleurotus ostreatus) and lion’s mane (Hericium erinaceus) mushrooms grown on two substrates: oak sawdust and whole, chipped hemp stalks.
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Conduct a comparative cost analysis evaluating input costs, labor requirements, and output efficiency for each substrate.
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Measure mycelial growth speed and total time to harvest as indicators of substrate performance and production efficiency.
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Assess contamination incidence and functional tolerance across substrate types.
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Evaluate the accessibility, traceability, and sustainability of sourcing each substrate in the Pacific Northwest.
Education & Outreach Objectives
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Produce a comprehensive grower manual on adapting mycelium to novel substrates, using hemp stalks as the primary case study.
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Create a project video documenting the research process, methods, and outcomes in an accessible, visual format.
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Prepare and submit a scientific paper presenting the experimental design, data, and analysis for peer review.
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Co-author an Extension-style publication translating the research into applied guidance for growers and educators.
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Develop the NETTLE app (Network for Ecological Tools, Trade & Land-based Education) as a living platform to host project materials and facilitate ongoing resource-sharing and collaboration between hemp and mushroom farmers.
Each research and education objective is addressed in the corresponding sections below and supported by quantitative results, figures, and applied recommendations. Together, these objectives ensure that the project generates both rigorous data and durable infrastructure for knowledge-sharing, enabling the findings to remain active, adaptable, and farmer-driven beyond the life of the grant.