2018 ASHS Annual Conference

Temperature increment in low tunnels inside high tunnels (HT) could potentially promote plant productivity and extend the growing season, which benefits direct market oriented strawberry growers. This study aimed to find out the effect of low tunnels in the HT system on growth and yield of strawberries. Cultivars Albion and San Andreas were planted on September 1 (D1) & 29 (D2) in raised beds with low tunnel (LT) and without low tunnels (NLT) inside a high tunnel on NC A&T State University farm in Greensboro, NC (hardiness zone 7b). This is a two-year study with the 1^st season from Sept 2016 to May 2017 and the 2^nd season from Sept 2017 to May 2018. The result presented here is from the 1^st season and up to February 28 of the 2^nd season. In the 1^st season, LT did not significantly increase the total yield, but they slightly increased total marketable yield compared to NLT. LT had no significant effect on marketable and total yield before winter (Oct-Dec), during winter (Jan-Mar) and the peak harvest period (Apr-May). The peak harvest took place in April for both LT and NLT treatments. LT significantly increased total biomass of the whole season (581g/plant, dry weight) compared to NLT (526g/plant). There were no significant differences on leaf, crown, runner, and root biomass between LT and NLT treatments, although LT significantly increased fruit biomass compared to NLT. LT also did not significantly reduce the number of days to 50% bloom, although the first harvest occurred 6 days earlier than that of NLT. In the 2^nd season, the total yield with LT and NLT were not significantly different before winter and in January or February, although plants in LT bloomed earlier by 12 days than that in NLT. Our results suggest that including low tunnels in HT may increase yield during winter and shift the peak harvest to early April.