Boosts Fruit and Vegetable Yields

The primary economic benefit of SHARE farms is their ability to boosts yields.  Low-tech high tunnels commonly generate yields that are two to four times those of field grown produce.  These tunnels utilize drip irrigation but provide no auxiliary heat and the circulation and ventilation processes are managed by hand. 

By employing solar thermal heat and a semi or fully automated growing environment, SHARE farms boost yields beyond the capability of low tech high tunnels.

Below you'll find several university studies that document the potential of high tunnel farming. 

High Tunnel versus Field Grown Tomatoes

The University of Minnesota is currently running an exhaustive field study to compare organic high tunnel to outdoor grown vegetables. Published in 2009, the results demonstrate the dramatic increase in yields that high tunnels make possible.  It is important to note that the high tunnels used in this study did not utilize auxiliary heat. 

The chart shows how even without auxiliary heat the high tunnel tomato yields exceeded those grown outdoors by threefold in some cases.

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High Tunnel versus Field Grown Raspberries

The University of Minnesota collected data on field and high tunnel grown raspberries.  The raspberries were grown inside a 30’ X 48’ high tunnel that employed drip irrigation and auxiliary propane heat to protect against frost damage.  The raspberry varieties were planted in 2008 and most of the data was collected in 2009 (the first full year of harvest).

The charts below display data from the Morris (above) and Grand Rapids (below) testing locations.

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High Tunnel versus Field Grown Blackberries

The commercial blackberry industry is virtually non-existent in the Upper Midwest because the harsh winters destroy the plants.  Our company has been awarded several grants to test the feasibility of using supplemental heat to overwinter blackberry brambles and move production much closer to home.  If our efforts prove successful, we'll be able to provide consumers in the area with fresh, locally grown blackberries.

Studies in warmer regions have already demonstrated the yield boosting potential of high tunnels.  Penn State University researchers  averaged 27,516 pounds per acre of blackberries, well above the national average of 5,400 pounds for field grown varieties. The yield results of the Penn State study (above) and national production data (below) are listed in the figures.

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