Season Extension Using Supplemental Soil Heat in a North Dakota High Tunnel for Warm Season Vegetable Production

Abstract

Vegetable production options in North Dakota are limited by environmental challenges. Combining soil heating cables and row covers within a high tunnel could protect crops from frost, extending the growing season. Three planting dates at three-week intervals, low tunnel coverings (clear plastic, light frost blanket, and heavy frost blanket), and supplemental soil heating (untreated and soil heating coils) were examined in Absaraka, ND for the effects on two basil and two snap bean cultivars. Soil heating cables increased cumulative harvested basil height by 20% over the untreated control in 2018, but not 2019. Overall, early basil plantings provided the greatest cumulative yield, with ‘Eleonora’ benefiting most from early planting. Cumulative bean yields were significantly increased with early plantings. However, soil heating and covers did not significantly affect cumulative bean yield in either year. Results indicate that in North Dakota, soil heating can increase yields with early plantings and appropriate cultivars.