Merging the Field with Greenhouses

High tunnels are a hybrid of open field and greenhouse production.  They are non-permanent structures similar in appearance to greenhouses but significantly less expensive.  They are constructed with horizontally supported metal hoops covered with heat retaining, light dispersing, anti-drip plastic.  The crops are planted in the ground and moisture regulated drip irrigation provides the optimal level of water and liquid fertilizers.  

The high tunnel side walls are rolled up and down by thermostatically controlled motors and exhaust fans are built into the ends walls.  Both features are critical for air flow management and temperature regulation. 

High tunnels have been used by growers in Europe and Asia for decades but only recently have begun to see widespread use in America. In cooler climates such as the Upper Midwest, their main purpose is to elevate temperatures a few degrees each day over a period of several weeks. Raising the temperature results in faster plant growth and higher yields. 

The plastic barrier is used to protect crops from winter rains and heavy summer storms, shelter plants from high winds, and inhibit insect outbreaks.  They can also be used to shade crops, protecting them from heat and sun scald.  And since they employ drip rather than foil irrigation, the risk of disease outbreaks is substantially reduced.


Scenic Valley Farms High Tunnels