Midwestern Hemp Database: Utilizing Grower-Cooperator Networks to Assess Variety Performance of Industrial Hemp Across the North Central Region

Progress report for ONC21-082

Project Type: Partnership
Funds awarded in 2021: $39,834.00
Projected End Date: 04/04/2023
Grant Recipient: University of Illinois Extension
Region: North Central
State: Illinois
Project Coordinator:
Chelsea Harbach, Ph.D.
University of Illinois Extension
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Project Information


Industrial hemp (Cannabis spp.) can be used to produce fiber, grain, and cannabinoids. A “new” crop to North Central agriculture, best management practices and performance of industrial hemp varieties have yet to be determined. Despite regional interest, a lack of university published resources regarding industrial hemp production and laboratory analysis exist.

To address these issues, our private-public partnership will use a multi-tiered approach to collect, analyze, and share data on variety performance and analytical methods throughout the NCR. Objectives of this program are 1). Grow the existing Midwestern Hemp Database by increasing the number of licensed hemp growers participating in the NCR; 2) Improve current data collection and visualization platforms for enhanced utility by stakeholders; 3) Establish a lab proficiency program among participating laboratories to evaluate analytical protocols across the region.

Data generated will improve the existing tool for growers to use when making seed company and variety decisions while providing transparency regarding laboratory protocols. Outreach is designed to expand existing regional partnerships, increase hemp production knowledge, and maximize economic and environmental sustainability of their production systems. A coordinated outreach plan, including the Midwestern Hemp Database website, written reports, conference presentations, and field days will facilitate the exchange of information.

Project Objectives:

Achievable objectives of the project include: 

  1. Grow the existing Midwestern Hemp Database to include at least 500 participating growers in 2023 across the NCR; this will be done by including additional states into the program with cooperation from their respective land grant institutions.    
  2. Select experienced grower-cooperators to conduct more stringent, but participatory, on-farm  trials using high potential varieties from prior research; data to be included in the Midwestern Hemp Database as "checks" to strengthen database. 
  3. Establish a proficiency program among participating laboratories to evaluate the various analytical methods being conducted in the region and how it may impact interstate commerce. 


Click linked name(s) to expand/collapse or show everyone's info
  • Barbara Barton
  • Keith Botsch
  • Ken Fanta
  • Alex Felt
  • Jared Glunt
  • Peter Gray
  • Mike Halsema
  • Luke Heidt
  • Tara Russell
  • Ami Smithenry
  • Lauren Virnoche
  • Bronwyn Aly


Materials and methods:


As a “new” crop to midwestern agriculture, best management practices (BMPs) and varietal performance of industrial hemp have yet to be determined. The BMPs yet to be developed include planting methods, variety performance, fertility requirements, rotational impacts, etc. Information from a needs-based assessment performed by hemp producers/processors showed that variety performance and cannabinoid development as the most pressing areas of research.

Obj 1) Grow the existing Midwestern Hemp Database (MHD) to include at least 500 participating growers in 2023

In 2020 and 2021, 180 hemp growers across the NCR contributed to the Midwestern Hemp Database. Crop management and variety performance data submitted by NCR hemp growers and variety trial participants were used to populate the MHD.  This public database provides timely data from commercial producers to support farmer decision-making.  Data is anonymized and aggregated to protect participants.  Specific protocols for agronomic data collection and floral sampling are distributed to participating growers who submit samples to partnering laboratories for analysis at a discounted rate. Using this approach, we can ensure the integrity of perhaps the most important and sensitive data for hemp growers: cannabinoid profiles. USDA sampling guidelines are followed and sent to participating, approved laboratories.

See attached Grower Protocol Midwestern Hemp Database

Obj 2) Recruit dedicated grower-cooperators to conduct participatory on-farm variety “checks” from 20+ NCR farms; data to be included in the Midwestern Hemp Database

Farmers will be involved in our project by conducting their own on-farm variety trials and contributing data to the Midwestern Hemp Database. Allowing growers to choose which verified varieties they want to grow allows them the freedom to experiment while contributing to a large data set at a discounted rate. Growers will also contribute further by sharing their experiences through outreach events and resources

To complement data being submitted by NCR hemp growers and strengthen the tool,  3+ growers per state will be recruited to conduct participatory on-farm variety “checks” including a consistent subset of high-potential varieties determined using results from 2020 university variety trials and data from the Midwestern Hemp Database. For on-farm trials, our team will supply seed/transplants/clones and cover the costs of cannabinoid testing. Growers will submit management, performance, and economic data via an online survey using the SeedLinked platform, as well as flower samples for cannabinoid analysis by partnering laboratories.  Grower data collection will emphasize experiential and qualitative information to complement the quantitative information generated by ongoing, coordinated university trials.  Participating growers will contribute to the development and delivery of outreach events and resources such as field days, conference presentations, and webinars.

See attached MHD Cultivar Check Program Grower Protocol

Research results and discussion:

Most high cannabinoid hemp grown in the Midwest will begin to flower during mid-August to early September, continuing reproductive growth until harvest in early October. The average harvest
date for full-season varieties in the Midwest is 45 days after flowering . Varieties/cultivars
in the Cultivar Check Program were harvested at 7 weeks ( ~49 days) after flowering was initiated.

Certain agronomic traits were evaluated including flowering date, biomass yield, floral yield, and plant
height. Agronomic data and other performance metrics were collected and entered in using SeedLinked. Yield components across and within varieties were extremely variable across locations; for this reason, university station trials may be more useful/accurate sources of information for those performance metrics. Anecdotally, across two years of agronomic data collection via the MHD, floral yields averaged 1.1 lb. per plant.

Data from the Cultivar Check Program illustrate that CBD:THC of the chosen hemp varieties were
relatively unaffected by sample timing, remaining consistent throughout flowering. This suggests that CBD:THC ratios are consistent throughout the flowering period at each location. This supports previous
literature done by researchers from Cornell University showing stable CBD:THC throughout
flowering. In addition, CBD:THC of stable cultivars only appear to be impacted by environmental factors on a limited basis; This also supports prior literature from various research studies. This information
is especially important for growers looking to utilize CBD:THC to make variety/cultivar selections and aid in harvest timing. Considering this information, CBD:THC ratios may be the most useful and
accurate indicator of compliant, profitable hemp. It should be noted that some genetic sources are less
impacted by environment or genotype* environment interactions; as such, heterogeneity across and
within varieties can make agronomic performance and cannabinoid development less predictable.
Due to the non-uniformity of the flowering process, unstable cultivars could reach maturity at different
points in the growing season, which could have adverse impacts on testing and harvesting strategies
at the field level. 

As cannabinoids do not begin to develop rapidly until flowering has been initiated, growers are
encouraged to delay sampling until after terminal flowering to eliminate unnecessary testing costs.
Compliance with USDA regulations is determined by showing that each hemp lot produces Total THC
<.3%. However, there is currently a great deal of variation across laboratory sample preparation
and analytical methods. This disparity between current laboratory procedures makes cannabinoid
analyses difficult to compare. As such, submitting samples though an approved, accredited laboratory
is recommended. 

This is a reminder that these varieties were chosen due to their track record and “Good Potential”
status. Data is presented in the following manner: cannabinoid data (Total THC (%),
Total CBD (%), and Total CBG (%)) are presented in terms of averages across all locations at each
time point for each variety. This decision was made due to this study and others illustrating stability
of CBD:THC throughout flowering and across environmental conditions for stable cultivars.
In addition, the data used at each time point in the following tables and includes taking
averages of the primary and secondary analysis.

Results of proficiency testing among partnering laboratories gave us the confidence to average
primary and secondary analysis to get a more representative sample. Both Total THC (%) and Total CBD (%) increased steadily throughout the flowering period. Across all variety entries during the
week 5 sampling period, the average value for Total THC was 0.20% ; by week 7, the average values for
Total THC increased to 0.37%. Of the six stable, CBD dominant cultivars grown via the Cultivar Check
Program, five (83%) exceeded the threshold for compliant hemp by the week 7 sampling period.
This data would suggest that optimal harvest for these cultivars will likely be 5 to 6 weeks (35 to 42
days) after flowering initiation to remain compliant. 

This trial shows that many CBD dominant cultivars exhibit a linear (or curvilinear) relationship between
Total CBD (%) and Total THC (%). Given this relationship, Total CBD (%) infrequently exceeds ~8%
without exceeding the regulatory threshold of 0.3% THC. This relationship suggests that cultivars with a
stable CBD:THC (~25:1 to 30:1) throughout flowering will help to maximize profitability while maintaining compliance. This data is supported by results found via the MHD and Cornell University.

The reality is most hemp cultivars currently on the market will go “hot” (Total THC >0.3%) if not
monitored appropriately during flowering. To illustrate, 29% of the samples tested were above
0.3% Total THC regulatory limit across the results from the MHD over the 2020 and 2021 growing
seasons (Alberti 2021). Growers are encouraged to test their crop frequently during later stages of
flowering to maximize production of cannabinoids while maintaining compliance.

Data from the MHD supports these findings as CBG dominant cultivars are not exhibiting a clear
quantifiable relationship between Total CBG (%) and Total (THC%). Importantly, many CBG dominant
cultivars contain lower amounts of Total THC (%) compared to CBD dominant counterparts. Across
the MHD data set, average Total THC(%) of CBD dominant cultivars was 0.258 (1181 entries)
compared to 0.075 for CBG dominant cultivars (200 entries). Data suggests that
CBG:THC are not stable with fluctuations occurring throughout the flowering period. The
highest CBG:THC occur during the earliest stages of flowering before decreasing significantly as
flowering progresses. Thus, utilization of CBG:THC an unreliable metric for evaluating
performance throughout the growing season.

Participation Summary
180 Farmers participating in research

Educational & Outreach Activities

60 Consultations
1 Curricula, factsheets or educational tools
2 Published press articles, newsletters
6 Webinars / talks / presentations

Participation Summary:

476 Farmers participated
Education/outreach description:

As this is early on in the project, select outputs (newsletter, journal articles, presentations) are limited. Research reports for this project are currently being constructed and shared via grower-cooperator networks. 

For the remainder of the winter/spring educational season, we will continue to share the results of the 2021 growing season at various conferences, seminars, and workshops. 

During the upcoming growing season, educational events/webinars will be hosted regularly via partnering growers to update program participants and stakeholders on our research efforts. 

Consultations are provided regularly for growers looking to utilize data for this project on their operations. This includes making variety selections in addition to providing insight on sampling and harvest recommendations. 



Learning Outcomes

30 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation

Project Outcomes

180 Farmers changed or adopted a practice
50 New working collaborations
Project outcomes:

Participating researchers and farmers will learn/identify suitable hemp varieties and production strategies in the NCR

Participating researchers to learn/identify various laboratory analytical methods and interpretations across states in the NCR

Participating researchers to learn general principles of on-farm trials to incorporate into other aspects of their farm 

Industrial hemp producers and processors may use the database to influence decisions regarding hemp variety selection, production strategies, and harvest schedules 

Industrial hemp producers and processors to utilize information from laboratory proficiency programs to inform decision-making regarding laboratory selection and interpretations of laboratory analysis. 

Information Products

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.