Exploring 60-Day Organic Crops for High Tunnels: Turnips and Ornamental Cut Kale

High tunnels can reduce weather-related production risks and provide season extension opportunities however, there is a lack of information about these systems for the Southeast region therefore we evaluated the performance of turnips (Brassica rapa, subsp. rapa) and ornamental cut kale (Brassica oleracea) as potential 60-day autumn crops grown under high tunnels. The trial was a split-plot design with four replications. The main factor was planting date (7 Oct. or 21 Oct.) and the sub-factor was cultivar. Black polypropylene landscape fabric was used as a mulch, automated sidewall curtains were opened when ambient air temperatures exceeded 15.6°C, and row covers were draped over plants when nighttime temperatures were predicted to be ≤0°C. A mixed ANOVA model analyzed marketable yield data for each crop type. A logistic regression assessed the nonmarketable percentage of yield. The following results reflect the first year of data from an ongoing two-year study. Turnips were harvested over time when individual roots reached the target diameter of ≥ 5.1cm. Both planting date and cultivar type had an effect on turnip root yield. The average marketable root weight as well as the root:shoot ratio was lower for the first planting date compared to the second planting date (p≤0.05). The turnip cultivars ‘Purple Top White Globe’ and ‘Royal Crown’ had a higher root:shoot ratio than ‘Golden Globe’ and ‘Amber Globe’ (p<0.01). The average days to harvest for the first and second turnip planting dates were 66 and 81 days, respectively after direct seeding. For the ornamental cut kale, each block was harvested when a minimum of 75% of plants reached the target height of >30cm and when contrasting colors had developed. Both planting date and cultivar type had an effect on kale stem length. The average kale stem length was greater for the first planting date compared to the second planting date (p<0.01). The kale cultivars ‘Crane Bicolor’ and ‘Lucir White’ had longer stems compared to ‘Crane Red’ (p<0.001) while ‘Crane Bicolor’ had greater stem and flower diameters compared to the other cultivars (p<0.001). The second planting date had a greater percentage of non-marketable stems, 15% compared to <1% for the first plant date, primarily related to limited stem length (15%). The average days to ornamental cut kale harvest for the first and second planting dates were 40 and 55 days, respectively after transplanting.