Dual Use Winter Vegetable Peas: Examining the Viability of Double Cropping in Zone 4

Progress report for ONE22-408

Project Type: Partnership
Funds awarded in 2022: $29,804.00
Projected End Date: 07/31/2024
Grant Recipient: University of Vermont
Region: Northeast
State: Vermont
Project Leader:
Dr. Eric Bishop-von Wettberg
University of Vermont
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Project Information


Bone Mountain Farm and researchers from the University of Vermont are testing the winter survival and operational barriers to the adoption of winter vegetable peas, a dual-use crop that provides both the ecological value of nitrogen-fixing winter cover crop and a profitable early-season vegetable. We are examining the strength of deer herbivory, and tracking barriers such as labor and production costs.

Project Objectives:
  1. Evaluate Austrian winter pea forage-type cultivars against new developed cultivars on a high elevation farm at the edge of zone four in the Champlain Valley.
  2. Identify any incidence other than cold stress that may significantly hinder the production of winter peas in the trial ecological region.
  3. Find ways to deal with barriers that limit winter pea uptake by integrating winter pea production with minimal interference on the existing production plan of our Collaborative Farmer.

      Vegetable producers face significant challenges in maintaining soil fertility, reducing erosion, and nutrient loss. A sustainable strategy to combat these challenges is cover cropping, which is the method of planting a crop, not for its food production, but for its ability to manage soil erosion, soil quality, water, pathogens, and biodiversity (Reeve 2018; Kaye and Quemada 2017).  Cover cropping accomplishes this by lowering the need for agricultural inputs (fertilizers, pesticides, herbicides, etc.) required by farmers, thus lowering their costs and limiting the amount of chemicals being released into the environment by agricultural runoff (e.g., SARE 2016, Reeve 2018).  Before the following cash crop, a cover crop is terminated, either with pesticides or by turning it into the field (Keene et al., 2017). However, for many producers, the cost of seed and the interference with other farm operations (such as early season planting) make cover crop implementation extremely challenging (Roesch-McNally et al., 2018; Bergtold et al., 2019; Duke et al, 2022).  Dual-use crops that provide the ecological function of a cover crop but are harvested as a food crop can provide multiple benefits to farms. If these dual-use crops can be grown in a fashion that allows for double cropping, farmers can harvest twice the output from the same land base, improving soil health and providing extra income from a second cash crop.


      A popular overwintering legume cover crop used by vegetable producers in warmer parts of the United States is winter pea (e.g., NRCS 2011). Our recent research has shown that if planted sufficiently deep, new winter-tolerant pea cultivars can survive well when planted as late as the end of September in the Champlain Valley (Marques 2020, Brefo et al, in preparation). Yet most winter pea cultivars currently planted in our area are Austrian winter pea types that are primarily used for livestock forage due to their high starch content.  However, efforts to cross traits of vegetable peas, such as sweet pods, into a cold tolerant background are beginning to yield dual-use peas. 

      Winter-hardy vegetable peas could be transformative if they allowed for double cropping.  By planting them in the autumn and harvesting them before many spring or summer vegetables are even planted, they can provide the benefit of a cover crop by stabilizing soil and fixing nitrogen, but also provide income early in the growing season.  With a harvest early in spring, before many soils have dried sufficiently to plant a summer crop, they should not impinge on production of summer vegetables.

      Vegetable pea cultivars come in several forms.  Most have sweeter pods, with a lower starch content in seeds.  Others have tendrils in place of leaves, and leaflets on tendrils, which improve their quality as greens.  The USDA ARS breeding program under the direction of Dr. Rebecca McGee has crossed these traits, which are controlled by a small number of genes, into a cold tolerant Austrian winter pea background. In our first trial with these new cultivars, currently underway, shows that these dual-use peas have equivalent overwinter survival to Austrian winter peas.

      Although dual-use peas that facilitate double cropping could be a boon for small, diversified vegetable farm that often struggle to use cover crops, barriers remain to their uptake (e.g., (Roesch-McNally et al., 2018; Bergtold et al., 2019; Duke et al, 2022).  Research is needed on operational barriers, such as lack of planters or cropping schedules for late season crops, which may hinder smaller or new farmers from adopting covering cropping practices.  Furthermore, at the edges of zone four we are not certain that these peas can tolerate colder, longer winters.


Click linked name(s) to expand/collapse or show everyone's info
  • Tucker Andrews - Producer
  • Dr. Rebecca McGee (Researcher)
  • Heron Breen - Producer (Researcher)
  • Emmanuel Brefo (Researcher)
  • Deb Heleba (Researcher)


Materials and methods:

We are performing a collaborative replicated field trial experiment with the aim of exploring how vegetable-type winter pea cultivars perform at the cold fringe of zone four, on a higher elevation farm at the edge of the Champlain Valley.  We aim to perform this over two seasons, as annual variability in snow cover is growing, and can have a significant impact on overwinter survival.

      Prior to planting, soil tests were performed.  We will use the comprehensive assessment of soil health (CASH) to provide a complete picture of soil conditions.  The same test will be performed after the pea crop, to measure changes in soil condition.  The CASH test measures multiple aspects of soil chemistry and physical structure to give an overall assessment of soil condition. Bed preparation followed Bone Mountain’s current practices for preparing beds for summer cash crops.  Planting was performed with the Jang TD-1 Precision Seeder, to get seeds planted deeply.  Prior to planting, seeds will be mixed with commercial inoculum to ensure the presence of suitable rhizobia for peas.  We planted the first year on  September 15th.

      The trial has four treatments, with three replicates of cultivars in each treatment combination.  Peas were either be planted alone interplanted with rows of oats, a common cover crop cereal that may help insulate peas before it is freeze-killed.  Furthermore, peas will either be fenced to protect from herbivores (rabbits, deer), or left unfenced; this will allow us to measure herbivore pressure.  Into these four treatments, we planted three cultivars of vegetable type ​​winter hardy peas.  In addition, we will plant three Austrian winter peas (cultivars Windham, Blaze, and Coyote) as positive controls for overwinter survival, and two summer peas (Emerald and Amigo) as negative controls.  We expect the second season to be a larger version of the first-year trial, but potentially integrating lessons learned in the first year.

     Following planting, we measured seedling emergence before the onset of snow, the density and diversity of weed species, the presence of any diseases.  In the spring we will measure overwinter survival, days to flowering, days to maturity, yield, and quality measures.  We will use multivariate ANOVA to measure differences between the vegetable types and the Austrian winter peas, and the impact of the two treatments (triticale/no triticale and fence/no fence).  Statistical comparisons will be made in the R-statistical coding language. 

      We are working with our farm partner to accurately track expenditures related to this effort using a custom-designed form in Google Sheets. This approach allows our farm partners to easily enter data as costs (or effort) are incurred, and offers the University research team ongoing, real-time access to expenditure data throughout the lifecycle of the trial plots. Expense reporting will be maintained in separate worksheets for each of the test plots. Itemized details for field inputs (seeds, bed preparation, fencing), labor (planting, field maintenance, harvesting and processing), and equipment will be entered into the worksheets. The form will be accessible for entering and evaluating plot-level data in both field (via cell phone or tablet) and office settings. Following data entry, which will occur throughout the trial, plot-level summary reports will be generated and shared. Our farm partner will be consulted on the design of and delivery mechanism(s) for these information packets to ensure their utility. We will use this information to assess the economic viability of winter vegetable peas.  We need to know how costly winter peas to produce before advising on them.

The second year trial is underway.

Research results and discussion:

In the first season, we had a partially successful trial.  We had high deer pressure, and the fence we used was blown over by moving snow.  Consequently, we did not observe significant differences based on fencing.  Our cold-senstive controls were successfully winter killed.  Among the cold tolerant varieties, we had high survival (50-90%) among the winter tolerant varieties.  There were varietal differences among 7 cultivars, but the overwintering vegetable types performed as well on average (no statistical difference) as the Austrian winter peas.

We are currently performing a second winter trial.  We think that fencing will pose another barrier to adopting overwintering vegetable peas.

Research conclusions:

We have not yet reached research conclusions, but have a strong inkling of our likely results.  We have observed that the winter hardy peas can survive the more challenge conditions at our high elevation partner farm.  However, they need better fencing.  The winter of 2022-2023 has had greater temperature variation, with warm spells, than other recent winters.  This impacted the durability of our plastic fence.  

We believe that overwintering peas are a viable option, but that the real challenge is spring harvest.  Most farmers want to get on with summer, and are focused on planting high-value crops.  They do not have the labor or interest in harvesting peas.  In most settings they will just till them in, if they use them at all.  It is home gardeners and specialty growers who we think are our best market.


We have brought in Heron Breed to advise on reaching seed companies with this information, to explore possible seed company interest.  We are are also working with Deb Heleba in the UVM master gardener program to expand planting out to master gardeners to see if we have more uptake this way.

Participation Summary
3 Farmers participating in research

Education & Outreach Activities and Participation Summary

4 Consultations
1 On-farm demonstrations
1 Online trainings
1 Published press articles, newsletters
1 Webinars / talks / presentations
1 Workshop field days

Participation Summary:

4 Farmers participated
3 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:

The project has several outreach components.  For a field day, Bone Mountain plans to participate in Vermont’s open farm week.  These field days will be critical in providing farmers with an in-person experience as well as an opportunity to interact with fellow farmers that are familiar with the varieties. We will publish project results on the UVM extension webpage where we have already built a page to share out winter pea work.  We expect to have a journal article in review in the next few months, which integrates data from this project and past trials.  We will present our novel approach to the farming community at Northeast conferences such as the New England Vegetable and Berry conference and NOFA-NY.  We are making more presentations this winter. We plan to do further outreach through social media and farming-oriented radio and TV programs, such as Vermont’s Across the Fence program.  We strategically selected these methods to disseminate information because farmers listed extension websites, presentations at conferences, and extension agents in a 2020 survey we distributed, as the primary preferred method to acquire new farming information. Collectively, our outreach methods will make the knowledge gathered from this project easily accessible to the entire Northeast farming community.

Learning Outcomes

1 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

As we just planted, we do not yet have many lessons learned or changes in knowledge, skills, or awareness to report.

Project Outcomes

2 Farmers changed or adopted a practice
1 New working collaboration
Project outcomes:

We are still within our first five months of the project, and do not yet have outcomes to report.  We were able to plant our overwintering trial, and are awaiting results.

Assessment of Project Approach and Areas of Further Study:

The project is supporting the msc research of Emmanuel Brefo.  He has gained subtantially from working with our farmer partner.  In addition, an undergraduate student, Eve Phillips, has benefitted fro the experience.

Tracking farmer expenses is not trivial, and we are searching for more seemless ways to do this.

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.