2018 ASHS Annual Conference

Fall-planted leafy greens are important crops for producers who harvest from high tunnels in late fall and winter. A survey of Indiana high tunnel producers identified planting schedules as an area in which more information is needed. We conducted trials to quantify the effect of planting date on yield of kale (Brassica oleracea var acephala DC), lettuce (Lactuca sativa L.), and spinach (Spinacia oleracea L.) grown in soil in unheated high tunnels at Wanatah, IN. 'Darkibor' kale was transplanted and 'Gazelle' spinach was seeded in tunnels on six dates at two-week intervals beginning 30 Aug. and ending 11 Nov. 2016. 'Salanova Red' and 'Green Reef' lettuce were transplanted in tunnels on 30 Aug., 15 Sept., and 14 Oct. Each tunnel was 914 X 1463 m and had three replications of each planting date for each crop. Kale leaves with blades at least 20 cm long were harvested approximately biweekly from 27 Sept. through 14 Mar. 2017. Cumulative kale yield was 7.47 kg•plot^-1 (1.11 m²) for the 30 Aug. planting, and 4.99, 2.08, 0.32, 0, and 0 kg•plot^-1 for subsequent planting dates. Days to first harvest from transplanting were 28, 26, 42, and 98 for the first four planting dates, respectively. Spinach leaves with blades at least 7 cm long were harvested from 0.372 m² in each plot weekly from 28 Sept. through 16 Nov. and then biweekly through 16 Mar. 2017. Cumulative spinach yield was 1.92 kg•plot^-1 for the 31 Aug. seeding and 1.49, 1.06, 0.73, 0.18, and 0.17 kg•plot^-1 for the subsequent planting dates. Days to first harvest from planting were 28, 28, 36, 48, 120, and 126 for the six planting dates, respectively. A single lettuce head of each variety was harvested from each plot biweekly once most heads for that planting date were 15 cm across. Harvest began 29 Sept. and 6 Oct. for the first and second plantings, respectively, and ended 13 Dec., after which heads were not marketable. The 14 Oct. planting was harvested from 1 Dec. through 18 Apr. 2017. Cumulative yield per m² of harvested area was 4.04, 4.94, and 1.91 kg for 'Green Reef', and 3.63, 2.95, and 2.53 kg for 'Salanova Red', for the Aug., Sept. and Oct. plantings, respectively. These results contribute to available information on planting date and yield in high tunnels that will help producers plan crop schedules to optimize their production systems.