Frequent application of composts and manures can lead to soil health challenges in high tunnels, particularly phosphorus accumulation and increasing soil pH. The goal of this project is to enable organic farmers in the Midwest and Northeast regions to reduce reliance on manure-based fertility by identifying effective species and timings for legume cover crops in high tunnels. Field trials are planned from 2024-26 that will investigate the performance and outcomes of legume cover crops in high tunnel rotations. The research team, through past experiments and consultation with farmer partners, has identified three time slots in which cover crops may fit into high tunnel vegetable systems in northern climates, and legume cover crops likely to succeed in each of these time slots.

We are recruiting a large number of organic farmers in these regions to participate in on-farm trials to evaluate how legume cover crops perform in their own farming systems. Farmers will not be asked to plant replicated arrangements of the trial plots on their farms. Instead, researchers will plant all of the cover crop options in replicated plots on a research station, while each participating farmer plants one plot of each of the cover crop options that they select. Farmers can select between two levels of participation and compensation, depending on the amount of time and effort they are willing to commit. You can read the full trial instructions, detailed species and timing menu, and farmer expectations for each level here.

An informational webinar for those interested in participating will be held on Zoom on Monday, February 2, 2026 at noon CT/ 1pm ET. Register for the webinar here.