Organic Winter Production Scheduling in Unheated High Tunnels.

Project Overview

Project Type: Professional + Producer
Funds awarded in 2010: $38,358.00
Projected End Date: 12/31/2010
Region: Western
State: Colorado
Principal Investigator:
Frank Stonaker
Colorado State University


  • Vegetables: beets, carrots, greens (leafy), radishes (culinary), turnips


  • Crop Production: relay cropping
  • Education and Training: decision support system, demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research, workshop, technical assistance
  • Energy: energy conservation/efficiency
  • Farm Business Management: new enterprise development, budgets/cost and returns, community-supported agriculture, feasibility study, risk management
  • Pest Management: disease vectors, mulching - plastic, row covers (for pests)
  • Production Systems: general crop production
  • Sustainable Communities: local and regional food systems, partnerships

    Proposal abstract:

    Winter vegetable production in unheated high tunnels with the aid of floating row covers can impact a vegetable operation in multiple positive ways by extending the employment period, providing an additional source of income during the winter months, and maintaining a continuous presence in the market without requiring the large investment of a conventional greenhouse. Traditional greenhouses can cost up to $20.00 a square foot where as a high tunnel can be constructed for as low as $1.50 a square foot. This large price difference allows growers flexibility in what they can afford to grow in a high tunnel and allows for a faster return on their investment. Also, by extending the growing and harvest season, high tunnels can also increase the grower’s local market share while providing consumers with access to local and fresh produce throughout the winter. Markets for locally grown winter vegetables in Colorado are far from saturated and all of the growers who are participating in the study report that demand exceeds their ability to supply winter produce to their consumers. However, despite this clear market opportunity there are still production methods specific to Colorado and the Rocky Mountain West that need refining. Two major production methods that need refining are: 1) the scheduling of successive plantings to ensure a continuous harvest 2) developing a better knowledge of the time requirement of different crops to reach harvestable size throughout the winter months. Thus our objective is to determine the proper scheduling of five different hardy vegetable crops; mustard greens (Brassica juncea), carrots (Daucua carota), lettuce (Lactuca sativa), radish (Raphanus sativas), and spinach (Spinacia oleracea). Cultivars of each crop have been screened in a previous pilot project evaluating cold hardiness of winter greens at CSU’s Horticulture Field Research Center during the winter of 2008/2009. This project will involve the collaboration of high tunnel growers from three production regions around the state of Colorado. Each of the growers has several years of high tunnel production and direct marketing experience. The experiment is designed to identify regional differences and/or similarities in crop responses while following a common production and evaluation protocol. To better understand the effect of winter planting schedules in unheated high tunnels, each crop will be planted on monthly intervals starting in October and ending in March for a total of five planting dates. Each grower will be provided instructions, planting maps, planting schedules, and the supplies required to follow a common production, harvest and evaluation protocol. Winter vegetable production provides growers an extended seasonal employment and income stream with a relatively low initial investment. Winter vegetable production benefits consumers because it provides a local and fresh produce option. Finally, winter vegetable production in unheated high tunnels can lessen the environmental impact of agriculture by decreasing fossil fuel consumption in both transportation of produce from warmer climates and also by eliminating fossil fuel burning as a heat source.

    Project objectives from proposal:

    The objective of this study is to expand the understanding of how to best utilize high tunnels for organic winter vegetable production throughout Colorado. Specifically, we aim to identify successful production scheduling of successive plantings to ensure a continuous harvest and develop a better understanding of the time requirement of different crops to reach harvestable size throughout the winter months. To achieve these objectives, we are conducting repeated experiments at 6 different farm operations beginning in October 2010 and continuing through March 2011. Additionally, we will collect temperature data at each farm both within and outside of the high tunnels to observe the degree of protection that high tunnels provide and crop response to these conditions. In combination with this data, yield results, and days to harvest from the successive plantings, we will determine the best timing of successional plantings of 5 distinct vegetable crops (mustard greens, carrots, lettuce, radish, and spinach) in order to achieve marketable harvests throughout the winter.

    The benefits and impacts of this research for intermountain regional producers will include access to information about production techniques that promise to increase marketing opportunities, profits, on farm employment, diversification of the farming operation, and increase local consumption of produce. The relative low cost of high tunnel installation and operation minimize adoption obstacles for beginning and low income producers.

    By extending the growing and harvest season, growers who utilize high tunnels could capture more of consumer’s income spent of food during the winter months where without employing high tunnels, consumers are forced to purchase produce that is not grown locally. Furthermore, high tunnels allow growers to diversify their operation and spread more of the inherent economic risks of farming out over a longer period of time by providing protection from hail and frost. Using high tunnels during the winter months allows farmers to command a premium price for their fresh produce in the winter months while also getting a head start in the spring. Finally, this research will impact intermountain west agriculture by increasing local consumption of produce. Growing cold tolerant vegetables in high tunnels will enhance local consumers’ food choices, food security and support local agricultural economies.

    The producers that collaborate in this project will be surveyed after the completion of the study to determine the degree of adoption of the production schedules that were trialed. Their suggestions regarding improvements to the methods will be considered for future evaluation. During the two field days and three conferences at which results will be presented, the audience will be surveyed to determine the likelihood these production schedules and crops will be implemented in the audiences’ farming operations. The surveys will also inquire about the growers’ use of season extension methods, what their experience in season extension is, how the presentation changed their attitudes towards season extension, and what the likelihood is of them adding high tunnels to their production system.

    Our outreach plan first revolves around attending three major annual Colorado agricultural conferences, the Colorado State University (CSU) Specialty Crops and Horticulture Research Farm Field Day (July), Colorado Ag Big and Small Conference (February), and one of the monthly meetings of the Valley Organic Growers Association. We plan on giving talks at each of these conferences as well as a demonstration of the high tunnels and project results at the CSU summer field day. Each of these conferences attracts a diverse set of farmers both large and small organic and conventional. It is our hope that both conventional and organic producers will see the benefits of high tunnel production and consider incorporating this production method into their farming operation.

    Furthermore, we plan on organizing and hosting 3 on farm field days in February/March 2011 where growers can come and see the high tunnels while they are in winter production. All participating farms have expressed willingness to host a tour of their facility in order to facilitate these field days. At these field days there would be hands on demonstrations as well as time to discuss challenges and successes with these systems.

    Additionally, all materials produced will be posted on the CSU Specialty Crops and CSU extension websites. We will submit all materials or internet links to National Sustainable Agriculture Information Service, Appropriate Technology Transfer to Rural Areas (ATTRA) website where if accepted the information can benefit growers across the globe.

    We plan on publishing two distinct CSU Extension fact sheets. The first will present information about scheduling for continuous harvest, yield and days to harvest results of the crops grown. Combining this project's results with past research done at CSU, production, crop and cultivar recommendations for winter production in unheated high tunnels will be made.

    The second fact sheet will address the economics of winter production with suggestions for maximizing profits with winter production. Each of these fact sheets will be made available through the CSU's Specialty Crops web site as well as the CSU extension web site.

    Additionally, Project methods and results will be printed and made available to attendees at the conferences and farm field-days.

    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.