Economic and Yield Potential of Hemp Waste Material in Specialty Mushroom Substrate

Progress report for FW22-400

Project Type: Farmer/Rancher
Funds awarded in 2022: $24,282.00
Projected End Date: 08/31/2023
Host Institution Award ID: G363-22-W8613
Grant Recipient: Intentional Growth
Region: Western
State: Utah
Principal Investigator:
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Project Information


The main goals of this project are to study the potential of economic, nutritional and environmental benefits of using industrial hemp stalks as the nutrient source in standard mushroom media formulation.

Hemp stalks are a ubiquitous waste product following the reintroduction of industrial hemp as a valid agricultural commodity in the 2018 US Farm Bill. Specialty (edible) mushrooms are a separate commodity growing in popularity and economic value.

The project objectives are:

• Objective 1 and 4: Compare the cost analysis to yield potential of oyster mushrooms grown on hemp stalks to that of the commonly used straw material as the nutrient source in standard mushroom substrate formulation.

• Objective 2: Compare differences in the nutrient value of mushrooms grown with hemp stalks vs straw.

• Objective 3: Assess contamination rates of competing fungi (mold) in mushrooms grown on hemp stalks to that of straw.

We suspect that hemp stalks will provide an economic alternative that increases oyster mushroom yields and nutrition at a lower production cost. Additionally, hemp farmers will benefit from an increase income potential from a currently labeled waste product.

Research results will be disseminated via websites, workshops, community events, social media, and academic publications.

Project Objectives:

The project's research objectives are:

  • Compare the cost analysis to yield potential of oyster mushrooms grown on hemp stalks to that of the commonly used straw material as the nitrogen source in standard mushroom substrate formulation.
  • Compare differences in the nutrient value of mushrooms grown with hemp stalks vs straw.
  • Assess contamination rates of competing fungi (mold) in mushrooms grown on hemp stalks to that of straw.

The Educational Objectives of this project are:

  • Provide training and education at six on-farm tours (spring and fall 2023) for a minimum of 24 participants
  • Provide research results at one community presentation and two extension events (i.e. Q&A sessions), engaging over 40 participants
  • Engage 2,000 new followers on two social media platforms by Dec 2023
  • Present results from this study at two national/regional conferences, engaging with 80 participants
  • Produce a technical paper and short video report with results of this study by October 2023

June 7, 2022: Hemp stalk samples were sent to USU Analytical Laboratory (USUAL) for total elemental analysis. This data is available in the project report. 

WSARE Hemp Elemental Analysis

The first planting period (P1) was planned to begin mid-April. Project funding became available in June 2022, thus delaying purchase of required equipment and the P1 start date. P1 planting occurred on 8/9/2022.  Mushroom fruiting masses were measured in September and October. Mushroom sub-samples from this planting were sent to USUAL for analysis and the results are reported here. The second and third planting periods (P2 and P3) will continue in May and June 2023 (see 2023 updated wsare timeline).

Once all 3 planting periods are complete, the cost analysis, yield measurements, and laboratory results will be statistically analyzed and reported.

Farm tours were provided Jun to Sep 2022, and again will continue in summer 2023. Assimilation of results occur continuously as data acquired. The team will present the data at community and extension events. A website and social media campaign is currently being prepared and will be live May 2023. The team on target to present data at one or more regional conferences in 2023.

2023 updated wsare timeline


Click linked name(s) to expand/collapse or show everyone's info
  • Natasha Quinones-Rodriguez - Producer (Educator and Researcher)
  • Dr. Malgorzata Rycewicz - Producer (Educator and Researcher)
  • Dr. Nabil Youssef - Technical Advisor (Educator and Researcher)


Materials and methods:
Mushroom greenhouse with humidity and temperature control

2023 wsare project design

Small farming operations provide high levels of environmental stewardship and improve quality of life. They increase crop variety while steadily improving soil and water resources. Unfortunately, small farms are struggling and must find innovative means to maintain and improve profitability. Small industrial hemp farmers (under 10 acres) are facing a varied set of obstacles in a fast growing, controversial, volatile market; and specialty mushroom farmers are entering a growth phase in mushroom popularity and economic growth potential. Together, these industries could symbiotically work together to capitalize on the un-utilized hemp stalk supply and mushroom media demand.

The potential for recycling organic waste via fungi growth is essentially unlimited. Many commercial mushroom farmers choose sawdust and wood debris as primary substrate components. Mushroom growth habitat is additionally affected by structural composition, pH, and moisture. Intentional Growth Farm, LLC has dedicated an 8x10-foot greenhouse specifically built for vertical placement of mushroom bags in a temperature and humidity stable environment (figure 1).

Mushroom production consists of 3 primary stages: 1) propagation of mushroom culture; 2) inoculation of a grain media and incubation, and 3) launching the mycelium in grain media into a bulk substrate for fruiting. This project will bypass step 1 by using liquid mushroom cultures. Successful growing of mushroom in stages 2 and 3 greatly depends on uncontaminated environments to eliminate competition from other undesirable fungi and bacteria, which directly impacts growth of the mushroom fruit-body. Contamination vectors include the cultivator (the farmer), air, media, tools, inoculum, and mobile contamination units (i.e. insects and mites). The number of contaminants and the exposure time directly impact the severity of the contamination. Incubation of mushroom media and launching of grain into the substrate are especially susceptible to contamination. Complete media sterilization, filtered air-flow hood, and cultivator sanitation are among the most effective methods of reducing contamination rates.

Our research study will inoculate rye-grain media with a liquid culture and incubate for 2 weeks. This permits the mycelium to expand vigorously. Rye and grain media jars will be sterilized in a 10-gal All American pressure cooker. After 2 weeks of incubation, the grain media will be launched into a 1.5 lb bag of substrate and allowed to incubate for an additional 2 weeks. These large bags and the substrate in them also require pasteurization to kill off temperature-sensitive microorganisms. Pasteurization in the 10-gal pressure cookers has proven to inconsistent. After incubation, the bags will be strategically cut to allow gas flow exchange and the required humidity for the expanding mycelium to pin and fruit.

Research Design:

This research project will study yield, nutrient levels and contamination rates of 3 species of oyster mushrooms: blue oyster, pink oyster, and king oyster. A randomized block design with the 3 species and 2 substrate nutrient sources (hemp stalks vs. straw) will be used, repeating 3 times within the 2022 season (table 1). Each treatment will consist of 9-1.5 lb bags (54 bags total) of substrate, all of which will be pasteurized simultaneously in an 85-gallon mushroom substrate steamer to ensure complete, uniform pasteurization, and then inoculated with grain spawn. Oyster mushrooms typically fruit 3 to 5 weeks after inoculation of the substrate, at which point yield measurements and sub-samples for nutrient analysis will be taken.

The study will repeat three times. Grain media jars will be inoculated in mid-April (period 1), mid-May (period 2) and mid-June (period 3) to provide repetition and ensure statistical accountability.


Nutrient levels - Samples of straw and hemp stalks will be analyzed for total elemental composition by the USU Analytical Laboratory ( in April, prior to the 2022 growing season. This pre-season analysis will provide baseline data for nutrient levels of the two substrates and will be compared to data published and generally accepted in mushroom literature (such as Stamets, 2000).

Composite mushroom samples of each treatment will be taken after harvest for elemental tissue analysis. Composite samples will consist of 3 randomly chosen sub-samples from each treatment type, resulting in 6 composite samples {{ a) blue/hemp; b) blue/straw; c) pink/hemp; d) pink/straw; e) king/hemp; f) king/straw}} for each of the three grow-periods (April, May, June). The resulting 18 samples will be used to assess nutrient levels in each treatment type.

Yield - Yield will be measured and statistically analyzed for differences in value among the treatments. Each measurement will consist of weighing each individual bag and the corresponding mass of harvested mushroom growth.

Contamination - contamination is the growth of unwanted fungi/mold, bacteria and insects. Contamination reduces yield and profit. Contamination levels will be reported throughout the study as a concentration (i.e. 0% vs. 1-10% vs 11-25% vs fully contaminated). Jars or bag with contamination levels above 25% will be discarded to prevent contamination of the other bags and will be cited as a complete loss.

Economic Potential - Based on preliminary research conducted at IGF, we expect that the utilization of hemp stalks can be used to increase mushroom yield at a lower input cost than straw. The cost of materials including chipped hemp stalks, their regional availability, nutrient content, and performance (nutrient levels, yield and contamination rate) in mushroom substrate will be calculated and compared to the cost and performance of sawdust.

Research results and discussion:

The following are the preliminary results from P1 planting:

This 2022 WSARE project has successfully begun and is positioned to be completed in 2023. Funding availability delayed the start of our project from April to June 2022. At this time, we ordered the required equipment; 85-gal substrate streamer drum and a laminar flow hood, which were required for uniform pasteurization of all bags, tools and equipment, and a sterile environment during incubation. Due to the shift in timeline, we were able to complete one planting (P1). A second planting was begun on 9/12/2022, but the cold weather prevented the mushroom from fruiting. Therefore, only data from P1 are available for the preliminary analysis.  The second and third plantings will be accomplished May and June 2023, and data will be analyzed and disseminated quickly after it becomes available. 

Objective 1 - yield. Hemp stalks were successfully used as substrate to grow gourmet edible oyster mushrooms. Results from the first planting show that hemp produced higher yields of blue and pink oyster mushrooms. Yellow oyster mushrooms produced greater yields with straw substrate. 

Objective 2 - nutrient levels comparison of straw vs. hemp substrate. Straw has been extensively tested and reported (Stamets 2000). This project analyzed hemp to assess its potential in substrate use (see table WSARE Hemp Elemental Analysis). Additionally, the fruiting mushrooms grown on straw vs. hemp were analyzed for nutrients (see pdf USUAL P1 elemental analysis). No significant differences between straw-substrate and hemp-substrate mushrooms were found. 

WSARE Hemp Elemental Analysis

USUAL P1 elemental analysis

Objective 3 - contamination. Bags with straw substrate suffered from contamination more than bags with hemp substrate. Four (4) straw bags (vs. 1 hemp bag) was contaminated out of the 54 bags used in the study. 

Objective 4 - economic potential. Hemp hurd (the wasted byproduct of growing hemp for CBD) is available for sale online. Straw (a byproduct of wheat or other grain) is also available. An average price of hemp is less than the average price of straw:

hemp $0.66/lb (F-H15: 1/2" Hemp Hurds (

straw $1.49/lb (Rhino Seed & Landscaping Supply 10LB All Purpose Straw Bale - Esbenshades)

Participation Summary
3 Producers participating in research

Research Outcomes

Recommendations for sustainable agricultural production and future research:

Preliminary results show that hemp hurd (chipped stalks) can be successfully used as edible mushroom substrate.

The following are the in-progress recommendations based on the 2022 preliminary results:

Objective 1 - yield. Hemp stalks can be successfully used as substrate to grow gourmet edible oyster mushrooms, resulting in higher yields than using straw. 

Objective 2 - nutrient levels. There were no obvious differences between mushroom varieties grown with straw vs hemp substrate.

Objective 3 - contamination. Mushroom bags that used hemp had lower amounts of contamination.

Objective 4 - economic potential. hemp hurd is a waste product that is available online for less than straw, and often times can be gained for nearly free from local hemp farmers.

We tentatively recommend the use of hemp hurd as a material in mushroom substrate. We continue to expect that the economic value is greater, the yield higher, contamination lower and nutrient levels are similar. 

1 New working collaborations

Education and Outreach

2 Consultations
2 Curricula, factsheets or educational tools
3 On-farm demonstrations
2 Tours
1 Webinars / talks / presentations
1 Workshop field days

Participation Summary:

8 Farmers participated
1 Ag professionals participated
Education and outreach methods and analyses:

Three small farm tours were executed from May to September 2022, with a total of 8 participants (5 adults and 3 children). Three additional tours will take place May to September 2023. Future field days/farm tours will ask participants to fill out a SARE questionnaire. 

Preliminary results were gained from P1 (the first grow period). Nutrient and elemental analysis were performed at USU Analytical Labs.

Presentations at community and extension events are scheduled for May, June, and Sept 2023. Community events are planned at Bridgerland's Mushroom Society, Mobile Moon Coop, Stoke's Nature Center or Southern Idaho's Mycological Association throughout 2023.

Presentation of social media and website is on target, scheduled to begin in April 2023 through October 2023. Both social media and website are undergoing design and scheduling of posts to highlight the project's outcomes and possibilities.

Regional conference presentations are scheduled for June and August 2023. Our team has proposed to attend and present our research and findings at the Telluride Mushroom Festival and the Mushroom Society of Utah.

2023 updated wsare timeline

Education and outreach results:

Outreach and education results are highly preliminary to date due to the delayed start of our project. Our first farm tours showed us that involving the participant in the preparation of bags and harvesting of mushrooms increased enthusiasm and their desire to learn more. Future tours will all include a short educational component followed by participation in the construction of substrate bags, inoculation of mushroom mycelium into the bags under sterile conditions (utilizing the flow hood) and harvesting of fruited mushrooms. 

Agricultural producers are business folk at heart, and we expect that producers will become more interested/engaged in the results of this research when cost/value of straw vs hemp is explicitly shown.

Edible mushrooms do not require large tracks of land and can therefore be grown in dense urban communities. Our team is scheduled to present our findings at Salt Lake City's Mobile Moon Coop, a collective that aids communities & ecosystems through education, empowerment, and botanical stewardship. Flyers for the event, in English and Spanish, will be posted in international food shops, food co-ops, and other inner-city locations.

1 Farmers intend/plan to change their practice(s)
1 Farmers changed or adopted a practice

Education and Outreach Outcomes

Recommendations for education and outreach:

effectively disseminate ag research results - how? working towards providing online information and simple fact sheets

describe and assess how this project affects stakeholders' understanding of ag sustainability: One ag waste can be used to support another ag opportunity. This project's outreach has begun to help disseminate this information in a clear and simple fashion. It has been effective, and we will continue to use this outreach design/trajectory to continue to reach more stakeholders.

1 Producers reported gaining knowledge, attitude, skills and/or awareness as a result of the project
Non-producer stakeholders reported changes in knowledge, attitudes, skills and/or awareness as a result of project outreach
7 General public
2 Students
1 Ag Service Providers
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.