2017 ASHS Annual Conference

Rowcovers as low tunnel have been used successfully in protected production systems to extend the production season in temperate climates because the increased temperature and protection against light freezes. Kale and chard are grown in Virginia by rural and urban vegetable farmers due to the high value and demand in local direct sale markets. However, production and quality in summer and open fields is limited due to environmental conditions and pests. The objective of this study was to determine differences in growth and yield under row cover and insect net as low tunnel in comparison to open field. Also, the difference in insect injury was determined among treatments. Three experiments were conducted in the spring (17 March and 16 May) and late summer (6 Sept.) of 2016 at the Eastern Shore AREC in Painter, VA. Kale cultivars were ‘Toscano’ and ‘Fordhook Giant’, and Swiss chard cultivars were ‘Starbor’ and ‘Peppermint’. Transplant were grown in the greenhouse at 20-30°C for 3-4 weeks in soilless media before field planting. Rowcover increased temperature in all three studies, and consequently increased growth and yield. In the summer experiment, leaf area and biomass per plant, and their ratio (specific leaf area) were increased by 77%, 51%, and 18%, respectively. Consequently, yield under rowcover increased by 140%, 41%, and 38% in early spring, late spring, and summer, respectively. In addition, rowcover and insect net reduced the level of insect injury the resulted in higher marketable yields. In conclusion, kale and Swiss chard can be grown under rowcover throughout the season in Virginia. Rowcover protects against insects and increases yield of leafy vegetables and therefore it is a useful tool to improve sustainability of vegetable farmers and urban agrculture.