Fall planting of spinach (Spinacia oleracea L.) into high tunnels for harvest from late fall through early spring is widely practiced in the northeastern United States, but replicated studies focusing on this production system are lacking. The objectives of our study were to understand the effect of fall planting date (PD) and cultivar on yield and soluble solids content (SSC) of spinach. Three cultivars (Regiment, Space, and Tyee) were transplanted in unheated high tunnels in Durham, NH, in 2014–15 (Year 1) and 2015–16 (Year 2) at six different fall dates: 20 Sept., 30 Sept., 9 Oct., 19 Oct., 30 Oct., and 9 Nov. Five additional cultivars (Carmel, Corvair, Gazelle, Emperor, and Renegade) were included at the third date (9 Oct.) to compare yield and SSC among cultivars during winter months. A randomized complete block design with four replications was used for all experiments. Year and fall transplant date had a significant effect on total yield. Total yield of Year 2 was nearly double that of Year 1 for all PDs and cultivars. In both years, total yield decreased with later planting, such that yield from the 20 Sept. date was greater than a minimum of three of five subsequent PDs, depending on year. Total yield in spring (January through April) did not differ among the first four PDs in Year 1 or among any dates in Year 2, suggesting that a wide range of PDs will work well for those primarily interested in spring harvests. Combined analyses of the data from both years showed no significant differences in total yield among the eight cultivars planted only on 9 Oct. However, of the three cultivars grown at all PDs, Regiment produced significantly higher yields than Tyee. Harvest date, cultivar, and harvest date × cultivar affected leaf and petiole sap SSC in both years. SSC was most strongly negatively correlated with air and soil temperatures at a 10-day interval in Year 1 (R 2 = 0.61 and 0.64, respectively) and a 7-day interval in Year 2 (R 2 = 0.78 and 0.69, respectively). ‘Gazelle’ and ‘Emperor’ contained among the highest SSC in both years. Our work demonstrates total yield is highly dependent on fall PD and the growing conditions of a given year.
Kaitlyn M. Orde, Connor Eaton and Rebecca G. Sideman
Kaitlyn M. Orde and Rebecca Grube Sideman
Day-neutral strawberry (Fragaria ×ananassa) cultivars show promise for extending the fruiting season and increasing production in the northeastern United States, but published research on cultivar yield in the region is lacking. Furthermore, few studies have investigated the effects of low tunnels on yield, fruit, and plant characteristics. We evaluated eight day-neutral cultivars (Albion, Aromas, Cabrillo, Monterey, Portola, San Andreas, Seascape, and Sweet Ann) on open beds and under low tunnels in two separate experiments conducted in 2017 and 2018. Cultivars began producing ripe fruit within 10 weeks of planting in both years, and continued producing fruit without interruption for 20 weeks (2017) and 18 weeks (2018). Annual total yield ranged from 234.9 to 497.8 g/plant and marketable yield ranged 126.4 to 389.1 g/plant, depending on cultivar and year. Cultivar significantly affected the percent marketable yield, late season yield, fruit size, soluble solids content (SSC), runner emergence, and plant size. Except for the cultivar Sweet Ann, low tunnels did not increase season-long marketable or total yield, but did increase the percent marketable yield for all cultivars in 2017, and most cultivars in 2018. Furthermore, marketable yield was significantly greater under low tunnels than open beds during 6 late-season weeks in 2018. Fruit SSC was greater under low tunnels in 2018, and low tunnels reduced runner emergence for certain cultivars. Season-long average air temperatures were higher under low tunnels, but the greatest temperature differences occurred when low tunnels were closed. We demonstrate that day-neutral cultivars can produce high annual yields in New England, but that cultivar selection is paramount.