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 types and construction
  • 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


    We evaluated three high tunnel designs of various heat retention capacities (single layer [SL], double layer [DL] and DL plus a water heat sink [DL+B]) across different climatic zones in the Southwest for their potential to profitably produce winter greens. Lettuce and spinach were planted in fall in AZ, CO and NM. Results demonstrate that high tunnels in combination with row cover can provide adequate winter protection for greens, and the DL+B design produced the highest daily air and soil temperature minimums. An economic analysis indicates that the SL and DL designs had the highest probabilities of producing positive returns.

    Project objectives:

    1) To quantify the differences between three passive-solar high tunnel designs of different expense and heat-retention capacities (SL, DL and DL+B designs) to assess their potential to provide a suitable environment for winter production of leafy greens.

    2) To evaluate growth and yield of one spinach and one lettuce cultivar at three planting dates (on or near October 25, November 20 and December 15) within each tunnel.

    3) To conduct economic analyses to determine the probability of producing positive returns in each tunnel design, planting date and crop scenario.

    4) 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.