(23) High Tunnels for High Latitude Snap Bean Production

Abstract

Two snap bean (Phaseolus vulgaris L.) cultivars, `Provider' and `Concesa', were planted successionally in a high tunnel in Fairbanks, Alaska (64°49'N and 147°52'W), from late May to late July. For the entire growing season, air/soil temperatures averaged 1.7 °C/1.1 °C higher in the tunnel than the field. The temperature differential was, however, largely dependent on amount of high tunnel ventilation. With tunnel ends not yet erected in May, the air temperature difference averaged 0.5 °C while in September the difference was 2.5 °C in the enclosed tunnel. On average, both cultivars flowered 4 days earlier in the tunnel compared to the contiguous open field. `Provider' had high overall yields with no significant difference between the tunnel and the field, although the tunnel did offer protection from an early frost. `Provider' produced an average of 3454 g·m-2 in the tunnel and 2860 g·m-2 in the field. Average yields of `Concesa' inside the tunnel were significantly greater (P < 0.01), with 1719 g·m-2 compared to 756 g·m-2 in the open field. `Provider' pods were larger in diameter and more fibrous than `Concesa' pods, which we concluded were of improved quality with higher soluble solids content (°Brix refractometer readings). High tunnels could be an important way to provide an advantageous production environment for high quality cultivars without sacrificing the reliability of cold-tolerant cultivars. To consistently produce high quality snap beans to meet local Alaska fresh market demands, cultivars suited for high tunnel production need to be identified.