2019 ASHS Annual Conference

High tunnels are used to modify the environment in which a crop is grown by trapping solar energy from the sun, providing protection from unfavorable weather events, and extending the growing season in temperate regions. Warm-season crops, like tomato (Solanum lycopersicum L.), bell pepper (Capsicum annuum L.), and cucumber (Cucumis sativus L.), benefit from a longer, warmer growing season. This project evaluated cultivar trials of tomato, bell pepper and cucumber grown under high tunnel production and compared with an outdoor field over two growing seasons. Nine cultivars of each crop were grown with yield and quality assessed across years and experiment locations, western and eastern North Dakota. In the 2016 season, a difference of only 8 days occurred between the planting of the high tunnel and the field trials because construction of the high tunnel was not yet complete. This resulted in minimal differences in yields from inside the tunnel to outside. In 2017, the tomatoes and peppers were planted 14 days earlier resulting in 1.5 and 1.6 times more production than the field, respectively; and the cucumbers planted 27 days earlier resulted in almost 6 times more production in the high tunnel than the field. The 2017 high tunnel bell pepper trial at both locations was plagued with diseases and insect infestations resulting in the significant cultivar x location x year interaction. The main effect, cultivar was not significant which could indicate uniformity among cultivars. The uniformity of cultivars was also reflected in the outdoor field, with only significance found in the location x year interaction and the main effect, year. The cucumber cultivar ‘Corinto’ had the greatest yield from inside the high tunnel across years at 17 kg/plant^-1 in the western, and 20 kg/plant^-1 in the eastern trial. The field conditions proved to be more variable with no particular cultivar that stood out as the top producer in any given location or year. The western 2017 tomato high tunnel trial was also plagued with severe viruses resulting in the termination of the trial. The outside western tomato trial however, continued, as did the eastern high tunnel and field tomato trials for both years. High tunnels have extended the season, improved crop quality, and increased production relative to normal field growing conditions in North Dakota.