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Rodale Institute Industrial Hemp Research Project

Industrial hemp as a cash or cover crop to address weed pest issues and enhance soil health in organic agriculture.

Rodale Institute on April 19, 2018

Learn about Rodale Institute’s pioneering research on organic, no-till farming of hemp in Pennsylvania. Rodale’s work focuses on hemp’s benefit to soil health and crop rotations within a regenerative agriculture model, and will provide farmers the necessary tools and knowledge to successfully farm hemp commercially once federal prohibition of the crop is lifted. Be sure to also watch the Hemp History Week video at the bottom of this article that features the Rodale Institute’s hemp trials!


Pennsylvania’s Industrial Hemp Research Act

Industrial hemp, a versatile plant grown for its fiber, seed or oil, was a valuable cash crop and a major industry in Pennsylvania for more than 260 years. Due to its close relationship to the marijuana plant, hemp production became a casualty of a 1933 law banning marijuana, and was later named a Schedule 1 drug by the Controlled Substances Act of 1970.


Several states have authorized programs that aim to either assess the potential for industrial hemp or to actively support the adoption of industrial hemp by farmers. The Pennsylvania Department of Agriculture (PDA) is conducting an Industrial Hemp Research Pilot Program as authorized by section 7606 of the Agricultural Act of 2014 (Farm Bill) and Pennsylvania’s Industrial Hemp Research Act (3 Pa.C.S.A. 701-710) (Act 92), signed by Governor Wolf on July 20, 2016. This program allows researchers from institutions of higher education and growers contracting with PDA to apply and be approved for a research permit from PDA.


Rodale Institute welcomed Pennsylvania Secretary of Agriculture, Russell Redding, to the farm for a tour of the Industrial Hemp Research Project.


In 2017, Rodale Institute was one of 16 organizations that received a permit for the inaugural planting of hemp in Pennsylvania in more than 80 years, as part of the PA Department of Agriculture Industrial Hemp Pilot Project.


Rodale Institute
Our Project

With initial funding from Dr. Bronner’s, the institute initiated the four-year research project, beginning 2017, to evaluate industrial hemp varieties that are most suited to soil and climatic conditions in Pennsylvania, determine the potential of selected hemp varieties to suppress and manage weeds in an organic reduced tillage management system, and monitor soil health. Our research aims to identify which varieties of hemp will be effective for future use by organic farmers. Organic farmers are interested in growing hemp but require research-based information that will help them make informed decisions about integrating hemp into their rotations.


The project has two main components; a variety trial that aims to determine available varieties with greatest seed yield and biomass/fiber content and a weed suppression trial that aims to establish hemp as a dual cover and cash crop. Due to seed sourcing challenges, we were only able to secure three varieties for the trial, which are being assessed for weed suppression, viability (germination and stand counts), weed density and biomass, growth parameters (height, time and percentage of bud emergence, hemp biomass, and seed yield) as well as effect on soil physical and chemical properties.


Hemp Rodale Institute


The weed competition trial is evaluating the potential of hemp to act as a substitute cover crop (specifically to replace sorghum Sudan grass) in common organic tilled and no-till crop rotations, as a weed suppression cover crop (that also doubles up as cash crop).  We are especially interested in determining if hemp can suppress weeds enough to facilitate no-till planting of winter cover crops – the main ones in this region being cereal rye (normally rolled/crimped to plant soybeans) and hairy vetch (usually rolled/crimped to plant corn). Agronomic data being collected include weed density and biomass, growth parameters (height and biomass) as well as soil physical and chemical properties.


What we learned in year one

Preliminary results indicate that both hemp (Santhica – fiber variety) and sorghum Sudan grass substantially suppress weeds almost equally compared to control. Our preliminary data also indicate that hemp suppresses ragweed better than Sudan grass, while the latter suppresses lambsquarters better than hemp. Preliminary data also suggest that ‘Santhica’ hemp variety and Sudan grass reduce soil bulk density compared to the other two seed varieties and control. Additional data and statistical analyses are still being compiled.


Challenges we faced

The primary challenges experienced during this first year included sourcing the seed and working out the permitting process. The Commonwealth of Pennsylvania was in their first year of the permitting process as well as handling import and export red tape, so there were several learning curves that had to be worked out. Sourcing quality seed from international sellers was especially challenging. After substantial delay obtaining four varieties originally planned for the variety trial, one variety was found to have only have a 3% germination rate and had to be discarded. These challenges, however, provided valuable lessons that will be useful in overcoming similar future obstacles.




Posted by Rodale Institute

This article was written by Tara Caton, Dr. Emmanuel Omondi, and Ross Duffield from Rodale Institute. Rodale Institute is a nonprofit dedicated to pioneering organic farming through research and outreach. Rodale is currently in its second year of conducting a four year research project that focuses on utilizing industrial hemp as a cash or cover crop to address weed pest issues and enhance soil health in organic agriculture.