Document Type
Article
Publication Date
5-2014
Abstract
In 2012 we trialed 18 yellow storage onion varieties, three red onion varieties, and one sweet onion. The 2013 trial included 17 yellow storage onion varieties, 3 sweet yellow onion varieties, one sweet white variety, and 7 red onion varieties. The onion varieties were evaluated for yield, quality, storability, and suitability to plasticulture. All of the onions were started from seed in the greenhouse and transplanted into raised beds covered with plastic mulch. In 2012 transplanting took place on April 13 and beds were covered with conventional plastic mulch. In 2013 transplanting took place on April 30 and beds were covered with biodegradable BioTelo plastic mulch. In major production areas onions are direct-seeded into bare ground, however, this production system requires extensive use of herbicides and frequent hand weeding. The use of transplants and plastic mulch essentially eliminates weeding within the beds. Varieties differ in how reliably the bulbs form above the mulch, and bulbs that form partly or entirely below the mulch are at increased risk of thrips damage, bulb rot, and mis-shaped bulbs. Each 4-ft bed contained 3 rows of onions, with an in-row spacing of 4 inches. All fertilizers were incorporated during bed construction; water was provided by rainfall supplemented with overhead irrigation.