Seasonal High Tunnel Systems for Crops Update on interim standard 798 Technical and Program guidance National bulletin: National Bulletin: NRCS Idaho October, 2010

- 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

Condition Where Practice Applies

Criteria The seasonal tunnel structure must be planned, designed, and constructed in accordance with manufacturer’s recommendation

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 feet 2. 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 Utah State University s-fruits-herbs High Tunnel Sources