2018 ASHS Annual Conference

Using protected agriculture such as low tunnels can provide a substantial amount of plant protection during frost events. Cold damage to strawberry flowers and fruits occurs when temperatures are below 32 °F, which could result in yield loss throughout the season. The objective of this 2-year study (2016/17 and 2017/18) was to investigate if low tunnels would provide frost protection and increase yield of organically managed June-bearing strawberries in the annual plasticulture system. This study was conducted at the North Carolina Agricultural and Technical State University research farm in Greensboro, North Carolina (hardiness zone 7). June-bearing varieties were Benicia, Camino Real, Florida Radiance and Winterstar. Low tunnels consisted of metal wire hoops covered with 1­mil perforated plastic. The experimental design was a completely randomized design (CRD), conducted as a split­plot with three replications. The main plots were beds covered with low tunnels (LT) or without low tunnels; the split plots were cultivars. All strawberry plants experienced cold damage to flowers and fruit from December to March each season. Low tunnels were able to provide some degrees of frost protection in both years. In the 2016/17 season, damage to open flowers in December was 41% with LT and 33% without LT. In January, there were a lower number of fruits and flowers present at the time and no significant differences between the treatments existed. In February, less flowers were damaged with LT (8.6%) than without LT(10.5%). In the 2017/18 season, flowers and fruit damages to frosts were 22.7% and 8.7% with LT and 41.3% and 57.2% without LT, respectively. The frost protection by LT resulted in increased strawberry yield. In the 2016/17 season, the marketable yield in March was 20.45 g/plant with LT compared to 12.05 without LT; and in April, the number were 141.94 and 129.45 respectively. LT also reduced cull yield, for example in May 2017, the cull yield was 70.3 g/plant with LT and 97.7 g/plant without LT. Our results indicated that LT can significantly increase marketable yields of organically managed strawberries by protecting plant, flowers and fruit from cold damages in the field.