Seasonal High Tunnel Systems for Crops
Update on interim standard 798
Technical and Program guidance
National bulletin: 190-10-10 National Bulletin: 190-10-12
NRCS IdahoOctober, 2010
Seasonal High Tunnel - Definition:
A seasonal polyethylene covered structure with no electrical, heating, and/or mechanical ventilation systems that is used to cover crops and extend the season in an environmentally friendly manner
• Practice lifespan: 4 years
•Currently (2011) only available under the Organic EQIP payment schedule.
- Improve plant quality
- Improve soil quality
- Improve water quality from reduced nutrient and pesticide transport
- Improve air quality through reduced transportation input
- Reduced energy use through local consumption
Purposes
• Cropland where the growing season extension is needed due to climate
• Crops grown in natural soil profile–Specialty crops like vegetables and small fruits
• Raised beds allowed, but not crops on benches or in pots
Condition Where Practice Applies
• Tunnel shall be constructed of metal, wood, or durable plastic and be at least 6 ft in height
Criteria• The seasonal tunnel structure must be planned, designed, and constructed in accordance with manufacturer’s recommendation
• Shape• Ground Posts and Bows• Purlins and Truss Supports• Sidewalls and Endwalls• Ventilation and Access • Covering (Polyethylene Plastic)
Elements of a High Tunnel
• “In climate conditions where snow loads may damage the structure, the tunnel cover shall be removed at the end of the growing season”
• As a minimum, a 6-mil greenhouse-grade, UV resistant polyethylene cover will be used•Standard from most manufactures
Criteria
• Maximum 2,178 square feet for a farming operation• Idaho NRCS has two payment rates:
1. Up to 1,000 square feet2. More than 1,000 square feet
Payment rate cap– Tunnel can be larger, but only pay up to 2,178 sq ft– Can have multiple tunnels– Can already have a tunnel
Payment Rate
Installation Considerations
Orientation
• NS for main season, EW for off season, maximize airflow crosswise• Distance from structures/shade
–2x height of nearest structure• Quality soil• Access to water for irrigation• Drainage
• Runoff shall be directed away from tunnel to avoid ponding
– Surface or underground outlets– Protected ground surface– Critical area planting
− Grassed waterways• If runoff empties onto ground surface, a detention basin, storage reservoir, or stable outlet shall be provided
Criteria
• Surface or ground outlets such as rock pads, rock filled trenches with subsurface drains, concrete and other erosion-resistant pads, or preformed channels may be used
• Seeding and vegetation shall be established on all disturbed earth surfaces
Criteria
• Plan appropriate measures to address:– Conservation crop rotation– Irrigation water management– Nutrient management– Pest management– Runoff from the structure
• Rotate location of the tunnel to reduce disease build up.
Considerations
For general information and suppliers of high tunnel systems see web sites:
hightunnels.org
University of Idaho http://www.extension.uidaho.edu/homegard.asp Utah State University https://extension.usu.edu/yardandgarden/htm/vegetables-fruits-herbs
High Tunnel Sources
