Uncovering the Efficacy of Hemp Byproduct as a Mushroom Growing Medium: Nurturing Symbiosis Between Local Farmers

Progress report for FW23-422

Project Type: Farmer/Rancher
Funds awarded in 2023: $25,000.00
Projected End Date: 12/31/2024
Host Institution Award ID: G314-23-W9982
Grant Recipient: Mountain Forage
Region: Western
State: Oregon
Principal Investigator:
Rebecca Winters
Mountain Forage
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Project Information


The substantial prevalence of hemp & recreational cannabis production in the Northwest region results in a large amount of underutilized agricultural byproduct (the stalk, or stem, of the plant) which has the potential to be a viable, economical, and sustainable resource in a separate (and similarly popular) industry: mushroom cultivation. Current popular mushroom substrates pose potential economic and/or agricultural downfalls. Although supplemented sawdust is generally the preferred fruiting substrate due to the wide variety of mushrooms that can grow on them, the sourcing of this material is rarely transparent. This can be an issue to mushroom farmers who care about the purity and sustainability of their product.

Our proposed study aims to uncover the viability of hemp stalks as a substrate for growing two commonly sought after mushroom varieties (blue oyster and lion’s mane) and, if proven to be a good resource, close the gap between hemp and mushroom farmers in the PNW. The goal is increasing commerce and sustainability in local businesses and the community by establishing an online platform whereby farmers can connect and exchange byproducts, materials, and experiences/education.

We believe that dried, ground hemp stalk, as a fruiting substrate material, will provide the same or better fruiting yield in pounds than hardwood sawdust (for blue oyster and lion's mane mushrooms) over the course of a 2 flush paradigm.

Project Objectives:

Research objectives:

  • Determine first and second flush rates (yield by pound) of blue oyster and lion’s mane mushrooms across 2 substrates: sawdust and hemp stalks
  • Cost analysis between the two substrate in regards to output
  • Analysis of mycelial growth (faster growth = faster turnover for more bags in a season)
  • Analysis of accessibility in our region (stats and networking on hemp and mushroom farms) as well as traceability (how transparent is sourcing information)

        Education objectives:

  •  Video + Written Guide demonstrating process for utilizing hemp stalks as mushroom substrate
  • Create a phone app to connect small local farmers in order to make use of/profit from/or trade viable byproducts from their ongoing operations
  • Curate at least 1,000 followers across at least two social media platforms (Facebook, instagram, and/or youtube, etc.)
  • Host a 2-day educational symposium to bring together varied agricultural professionals, entrepreneurs, and other interested individuals. There will be 10-15 speakers and a minimum of 75 attendees per day

Project begins June 1st, 2023. This will begin the onset of operation set-up and materials procurement. All hoop-house and growing spaces will be built and optimized for the project.

September 2023 all grow material will begin required processing and mixing.

Early October of 2023 will be the onset of inoculating grain with mushroom mycelium. Beginning late October or early November the first round of substrate bags will be assembled and myceliated. Harvest of the first round of experiments will be by the end of the year 2023.

Between the last harvest of the first round and the beginning of the second round, all spaces, hoop houses, etc. will be tended to and checked for issues. Additional grow materials for the second round will be processed.

Late February 2024 will be the onset of the second round, following the same formula as before; inoculating grain will begin in late February, substrate bags will be assembled and myceliated in late March with harvest scheduled for end of April, 2024. 


All dates are estimated and will be predominately subject to weather conditions. 


May through September of 2024 will be spent analyzing results of the study and preparing for the educational outreach. This will also be when the app goes into it's alpha stage and the instructional video will be finalized. 

The main educational event will be hosted toward the end of October, 2024. This will also mark the soft-launch of the app.

The report of our WSARE project will be presented by the end of November, 2024, and the app will be fully active. 


Click linked name(s) to expand/collapse or show everyone's info
  • Maud Powell - Technical Advisor
  • Rebecca Winters - Producer
  • Ben Yohai


Materials and methods:

Objective 1. Determine first and second flush rates (yield by pound) of blue oyster and lion’s mane mushrooms across 2 substrates: sawdust and hemp stalks.

    Our research will be focused on 4 groups which test our 2 variables: (1)substrate material and (2)mushroom variety. The study will be replicated in 3 shaded hoop houses (11ft x 21ft in dimension) on the same property, with each hoop house including a sample of each of the four groups (Table 1). The hoop houses will be equally divided between the 4 study groups, such that ~60sqft will be utilized for each group in each hoop house. 

    The 4 study groups are:

  • Blue Oyster mushrooms on sawdust substrate
  • Blue Oyster mushrooms on hemp stalk substrate
  • Lion’s Mane mushrooms on sawdust substrate
  • Lion’s Mane mushrooms on hemp stalk substrate


Table 1.




Hemp Stalks

Blue Oyster

Group 1

Group 2

Lion’s Mane

Group 3

Group 4


        Each group will undergo the same methods as writ below, with only the aforementioned variables between each group;


  1. All hemp stalks will be fully dried and then ground down to same-size small chips using a wood-chipper. The hemp stalks used in this study were pulled in the fall of 2022 and left to dry to completely (many months), then put through an industrial grade wood-chipper in mid-August. It is being considered to push the stalks through another wood-chipper for a finer material.
  2. Beginning in a sanitary lab space, quart jars of hydrated grain with gypsum will be sterilized in an auto-clave sterilizer, and then inoculated with mycelium (half of the jars will be oyster, half will be lion's mane).
  3. Jars will be moved to an incubation space, where they will be left to myceliate fully (until the jar is visually fully saturated with mycelium). The incubation space will be dark and climate controlled at about 75 degrees F. The jars will be periodically shaken by hand during this period, once at about 30% myceliation and again at about 80% (determined visually). 
  4. Substrate for each group type described above will be mixed and hydrated to field capacity (1.5 liters of water to 1kg of substrate material). The field capacity for each substrate will be checked at the beginning of the study for optimal hydration. 
  5. Substrate will be high-heat pasteurized for 18 hours.
  6. The pasteurized substrate will be put into 10lb auto-claveable bags with 2 jars of myceliated grain distributed evenly throughout each bag. The bags will be sealed and put back in the incubation area and left to myceliate fully (until the bag is visually fully saturated with mycelium)
  7. The bags will then be transferred to the fruiting area (the hoop houses described above) on basic shelving. Here the bags will be exposed to indirect light, air flow, higher CO2 levels, and higher humidity (80-90%). The bags will be sliced open at this stage.
  8. The bags will be checked periodically for primordial formation.
  9. Once fully matured, the fruiting bodies will be harvested and weighed with stems intact. This is the first flush.
  10. The bags will be left on the shelves and allowed to go through full fruiting again, following steps 8-9. This will be the second flush.



Objective 2: Cost/profit analysis between the two substrates in regards to output

    1. Cost analysis will focus on the procurement costs for each substrate base and differences in labor for mushroom cultivation across substrate bases and mushroom variety
    2. Profit analysis will focus on yield (in pounds) of each mushroom variety across substrate base, in conjunction with price/lb in current-day market, with cost subtracted out (this will be presented in a 1st, 2nd, and 1st + 2nd flush paradigm)
      1. COST OF GOODS SOLD (COGS) = substrate materials + substrate preparation labor + maintenance labor + harvesting labor 
      2. PROFIT = (yield x market price) - COGS



Objective 3: Analysis of mycelial growth (faster growth = faster turnover for more bags in a season)

    1. Document which group has the quickest turnover from inoculation to harvest, cross-referencing between each variable and considering known averages per mushroom type
    2. This will be measured in days from the day of inoculation to the day of harvest (the day of inoculation and day of harvests will each counts as 1 day) 


Objective 4: Analysis of accessibility in our region (stats and networking on hemp and mushroom farms) as well as traceability (how transparent is sourcing information)

    1. Investigate current market sourcing for substrate materials
    2. Inquire to businesses selling substrate material for all sourcing information available
    3. Release surveys to PNW agriculture business to determine attitudes toward inter-connectivity with other agricultural businesses, interests or concerns about materials sourcing and transparency, etc.
Research results and discussion:

No research results have been acquired to date; the first set of data is expected during May and June of 2024 and will be analyzed later in the year.

Participation Summary
1 Producers participating in research

Research Outcomes

Recommendations for sustainable agricultural production and future research:

This portion of the project is scheduled for later this year.

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

This portion of the project is scheduled for later this year.

Education and outreach results:

This portion of the project is scheduled for later this year.

Education and Outreach Outcomes

Recommendations for education and outreach:

This portion of the project is scheduled for later this year.

Key changes:
  • n/a

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.