Sliding High Tunnels

Sliding high tunnels extend the growing season, speed crop growth, reduce plant stress, and promote soil health using passive solar heating and passive ventilation.

What is a high tunnel?

High tunnel components

  1. Steel hoops covered by greenhouse plastic
  2. Roll-up sides to facilitate passive ventilation
  3. Spans several growing beds to allow soil-based production and farm worker movement

Cool season greens in high tunnel

High tunnel benefits

  • Extends the growing season to increase income potential
  • Reduces crop stress and disease pressure by protecting crops from wind and rain
  • Increases heat accumulation to speed crop development and increase diversity of cropping options
  • Extends period when fresh, locally-grown produce is available

Cucumbers in high tunnel

Why moveable?

  • Allows for optimal utilization of high tunnel structure
  • Exposes soil to natural processes -- such as rainfall, frost, and direct sunlight -- that help maintain soil health by leaching salts and killing soil-borne disease
  • Allows rotation of crops that benefit from season extension with crops that do not

Bed outside high tunnel

Why solar panels?

  • Powers electric motors that raise and lower roll-up sides and open and close vents for passive ventilation;
  • Powers a greenhouse computer that manages ventilation in response to interior temperature
  • Charges a battery to allow these processes to continue when the sun isn't shining

High tunnel in winter

Crop rotation

  • Nine year crop rotation through nine plots
  • Warm season and cool season crops alternate
  • Each tunnel is moved in spring and fall, so it is anchored in three different positions over the course of a year:
    1. Winter/spring position (cool season crops, carried over from previous fall)
    2. Summer position (warm season crops)
    3. Fall/winter position (cool season crops, carried into following year)

High tunnel positions

High tunnel crop rotation circle

high tunnel rotation table

High tunnel rotation table. Bold face indicates high tunnel position.