Growth and Yield of Organic Day-neutral Strawberries in Low Tunnels inside High Tunnel in North Carolina

Abstract

North Carolina’s fresh strawberry has a $21.4 million economic value, which is primarily from short-day cultivars in the annual plasticulture system. Organic and off-season day-neutral strawberries have higher prices than the conventional, field-grown strawberries. There have been no published studies on suitable cultivars, transplanting dates, and additional winter protection methods for day-neutral strawberry production in high tunnels in North Carolina. The objective of this study was to examine the effect of low tunnels, planting dates, and cultivars on growth, yield, and season extension potential of day-neutral strawberries in high tunnels. Plugs of day-neutral cultivars Albion and San Andreas were either transplanted in raised beds covered with low tunnels (LT) or without low tunnels (control, NLT), inside high tunnels on the N.C. A&T State University Farm (Greensboro, NC) on two different planting dates, which were 1 Sept. (D1) and 29 Sept. (D2) of 2016, or 9 Sept. (D1) and 10 Oct. (D2) of 2017, respectively. A completely randomized design with split-split plots was used. LT did not significantly affect the total yield and plant phenology, but they promoted the first harvest by a week compared with NLT, which resulted in higher yield during the winter of both years. D1 promoted about 24 days of earlier harvest than D2. ‘Albion’ had an earlier bloom and harvest date (by 1 to 3 weeks and 2 to 3 weeks, respectively) than ‘San Andreas’. Strawberry yield was low in the fall season, but it started to increase from January, peaked in April, and decreased again in May. D1 increased the whole season’s marketable yield of ‘Albion’ (430.3 g/plant), compared with that of ‘San Andreas’ (330.9 g/plant). During the winter, ‘Albion’ had a higher yield than ‘San Andreas’. Our study indicates that LT inside HT might not significantly improve the plant growth, early harvest, or total yield. Planting dates had no consistent effect on yield. It was suggested that ‘Albion’ should be considered for high winter yields, and ‘San Andreas’ be a cultivar with high yields of the entire season in high tunnels.