2017 ASHS Annual Conference

In the northeastern United States, ethnic crop production allows growers to connect to a diverse regional market. Amaranth (Amaranthus sp.) is eaten as a vegetable in over 50 countries worldwide and is tolerant of many biotic and abiotic stressors, making it an appealing addition to local production. Successful incorporation of this heat-loving crop requires region-focused cultivar selection, especially outside of the hottest summer months, and could be benefited by plasticulture production. Nine commercially-available cultivars and one heirloom variety were compared for performance in the northeastern temperate climate. Ten greenhouse-started plants of each variety were grown in raised beds with drip irrigation in a clear slitted 1-mil plastic low tunnel system. Treatments were arranged in a randomized complete block design with four replications, repeated seven times over the 2016 growing season. All varieties had significant drops in yield in the seventh planting (seeded 22 Aug.), and there was less yield variation between varieties in the third, fourth, and fifth plantings. ‘Miriah’ (A. tricolor) performed well in marketable fresh weight and stem to leaf ratio and was the most consistent across all plantings. A dwarf variety ‘White Leaf’ (A. mangostunus) consistently had relatively low yield but an excellent stem to leaf ratio. Stem to leaf ratios of ‘Red Garnet’ and ‘Red Callaloo’ (both A. viridis) were higher than half the varieties in the study across all plantings, but their cultures of origin traditionally stew stems with leaves. Growers should therefore consider the intersection of yield, stem to leaf ratio, and intended usage in cultivar selection for the northeast. Two commercial varieties, ‘Red Stripe’ and ‘Green Pointed Leaf,’ were used to evaluate plasticulture production. Three plasticulture treatments, (1) gothic-style high tunnel, (2) 1-mil clear slitted plastic low tunnel over raised bed with black plastic mulch, and (3) raised bed with black plastic mulch, were compared to an open field control plot. A split-plot experimental design with ten plants of each variety and four replications was repeated in June, July, and August 2016. No high tunnel plots showed significant difference from control plots in stem to leaf ratio or average plant yield. Low tunnel plots of both varieties had increased yield across all plantings, and improved stem to leaf ratios for all except the August planting. Yields exhibited a stronger correlation with soil temperature than air temperature, supporting the use of low-cost black plastic mulch and low tunnel systems over high tunnel structures.