Day-neutral (DN) strawberry (Fragaria ×ananassa) cultivars have potential to produce high yields in New England and greatly extend the period of regional strawberry production each year. However, DN strawberries have primarily been evaluated as an annual crop in cold climates; thus, winter hardiness and subsequent second-year spring yields are not well understood. Separate DN plantings were established as dormant bare-rooted plants in Durham, NH (U.S. Department of Agriculture hardiness zone 5b) in 2017 and 2018. During their first year of growth and fruit production, plants were grown under one of two cover treatments: a plastic-covered low tunnel or the traditional open field environment (open beds). In November, plants were covered with either straw much (Winter 2017–18) or rowcover (Winter 2018–19) for low-temperature protection during the winter months. In the spring of the second year when winter protection was removed, the same cover treatments (low tunnel or open bed) were re-administered to plants. Plant survival was affected by year and cultivar, with average survival rates of 82% and 98% in Spring 2018 and Spring 2019, respectively. Plant survival ranged from 34% (‘Monterey’) to 99% (‘Aromas’) in 2018, and 92% (‘Albion’) to 100% (‘San Andreas’ and ‘Seascape’) in 2019. Cultivar significantly affected total and marketable yields in both years, and marketable yields ranged from 35.8 to 167.3 g/plant in 2018 and 121.6 to 298.6 g/plant in 2019. The greatest marketable yields were produced by ‘Aromas’, ‘Cabrillo’, ‘San Andreas’, ‘Seascape’, and low-tunnel ‘Sweet Ann’. In 2019, ‘Cabrillo’, ‘San Andreas’, and ‘Seascape’ produced greater marketable yields during the 6-week second-year season than they had during the plants’ first year of fruit production the previous year, which spanned 18 weeks. Low tunnels hastened fruit ripening in the spring and result in earlier fruit harvests, and in 2019, marketable yields were significantly greater under low tunnels for the first 1 to 3 weeks, depending on cultivar. Total and marketable yields were unaffected by low tunnels in 2018, but were significantly greater under low tunnels in 2019. For cultivars in the 2019 experiment, the increase in marketable yield under low tunnels (compared with open beds) ranged from 92.3 to 166.5 g/plant, except for Sweet Ann, for which marketable yields were 256.6 g/plant greater under low tunnels than on open beds. Using a conservative direct market rate of $4.50/lb, the second-year spring yields produced in the present study had a direct market value of between $3899/ha and $95,647/ha, depending on cultivar and year. We demonstrate that it is not only possible to overwinter DN strawberry plants in northern New England, but that the second-year yield may even exceed first-year production. The results from the present study indicate great potential for profitability from an overwintered DN crop.
