Winter Production of Leafy Greens in the Southwestern USA using High Tunnels

Project Overview

Project Type: Research and Education
Funds awarded in 2009: $193,879.00
Projected End Date: 12/31/2013
Region: Western
State: New Mexico
Principal Investigator:
Dr. Steven Guldan
New Mexico State University

Annual Reports


  • Vegetables: greens (leafy)


  • Crop Production: cropping systems, high tunnels or hoop houses, organic fertilizers, season extension
  • Education and Training: demonstration, extension, on-farm/ranch research, participatory research, workshop
  • Energy: energy conservation/efficiency
  • Farm Business Management: agricultural finance, budgets/cost and returns
  • Production Systems: organic agriculture
  • Soil Management: green manures

    Proposal abstract:

    Farmers in much of the Southwestern U.S.A. are under pressure to divert agricultural land and water to residential and other non-agricultural uses, and they need alternatives to stay competitive and resist this trend. New marketing options are developing that encourage schools and other public institutions to purchase fresh produce from local farmers. To develop and take advantage of these markets, however, requires that farmers be able to reliably and cost-effectively produce product during the late fall, winter and early spring months. Lack of affordable methods for winter production currently limits grower market options, enterprise diversity and profits. In much of the Southwest, most winter days are sunny, yet nights (and in many areas, days) are below freezing. Passive-solar high tunnels should be ideally suited to this region. However, research on the use of these structures for winter production in medium-high elevation, semi-arid areas of the Southwest has not been conducted. Producer input at an NMSU-Alcalde strategic planning meeting established the need for year-round vegetable production research. We propose to evaluate in detail three passive-solar high tunnel designs (of different expense and heat-retention capacities) across three years and different climatic zones for their potential to profitably produce winter vegetables. We use the term “high tunnel” to refer to plastic-covered, walk-in, non-permanent structures that use no supplemental or artificial heat source to create suitable conditions for crop production. These units will be relatively inexpensive with the goal of making winter production opportunities available to resource-limited producers who make up the great majority of our producer clientele. Organically-managed lettuce and spinach will be planted November 10 and December 15 in the tunnels at nine study sites in AZ, CO and NM that reflect a range of agro-climatic zones from cold and short season (north and/or high elevation) to warm and long season (south). Tunnel temperature and photosynthetically active radiation (PAR) data will be collected to help growers select the appropriate tunnel design and crop/variety for their climate. Crop yields and economic analyses will determine productivity and profitability potential. Cooperator producers will assist in tunnel construction, seeding of research plots, collecting data at their farms, as well as participating in presenting and discussing results at field days and other educational events. Five producer and four college/university sites will be located across the study region of southern to northern New Mexico, southwestern Colorado and northeastern Arizona. College/university sites include New Mexico State University at Las Cruces (southern NM) and Alcalde (northern NM), Colorado State University at Hesperus (southwestern CO) and Diné College at Tsaile (northeastern AZ). Diné College is a tribal college that serves residents of the Navajo nation in AZ, NM and UT. Field day presentations (at least 10), nine high tunnel construction workshops, press releases, farming conference presentations and publications will extend results to farmers, extension professionals and the general public. Reliable winter high tunnel production will be water and energy efficient and will help farmers diversify into new local markets to increase profits and competitiveness. Consumers of the region will benefit by having fresh, local produce available for more of the year. Project evaluation will include feedback from cooperators and education event participants.

    Project objectives from proposal:

    *To quantify the differences between three passive-solar high tunnel designs of different expense and heat-retention capacities in order to assess their potential to provide a suitable environment for winter production of leafy greens.

    *To evaluate growth and yield of one spinach and one lettuce variety at two planting dates (November 10 and December 15) within each tunnel.

    *To conduct economic analyses to determine relative profitability of each tunnel design.

    *To distribute results and recommendations to farmers, researchers, extension educators and other agriculture personnel in NM, CO and AZ.

    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.