There is information on production of bunching onions under field conditions (Anonymous, 2002; Boyhan et al., 2009; Hodges, 2004). Expected yields from field production are ≈10,000 to 12,300 kg·ha−1 (Anonymous, 2002) equating to ≈1 to 1.23 kg·m−2. There is little scientifically evaluated information on bunching onion production under protected culture. In an environmental chamber, Broome and Peffley (2005) found that in-row distances of 15 to 20 mm benefitted plant development.
Shrefler et al. (2011) used hoop houses to produce spring transplants of bulb onions (A. cepa L. Cepa group). Although not completely analogous, it was determined that onions could be grown to bunching onion size over winter in Oklahoma using this type of protected culture. The transplants were started on a single date. It is not clear how planting date would affect production of bunching onions’ marketable yields. Russo (2004) reported on a method using seedling trays in a greenhouse to produce bulb onion transplants to be established in spring. These were also started on a single date and the products of neither of these methods were intended for consumption of immature plants. It is also unclear if type of protected culture would be cultivar-dependent. This experiment was undertaken to determine if marketable production of bunching onion cultivars was affected by planting date and type of protected culture.
Anonymous 2002 Green bunching onions. Allium fistulosum and Allium cepa. Commercial vegetable production guides. Oregon State University, Corvallis, OR. <http://nwrec.hort.oregonstate.edu/oniongr.html>
Boyhan, G.E., Granberry, D.M. & Kelley, W.T. 2009 Green onions. Commercial vegetable production. Cooperative Extension, The University of Georgia, Tifton, GA. <http://www.caes.uga.edu/publications/pubDetail.cfm?pk_id=6424>
Hodges, L. 2004 Growing scallions (green onions) for market gardeners. Paper 76. Historical materials from University of Nebraska Extension, Lincoln, NE. <http//digitalcommons.unl.edu/extensionhist/76>
Madrid, R., Navarro, F., Collados, I., Egea, C. & Alarcon, A.L. 1999 Development of colour in red pepper fruits in soilless culture J. Hort. Sci. Biotechnol. 74 175 180
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Russo, V.M. 2006 Biological amendment, fertilizer rate, and irrigation regime for organic bell pepper transplant production HortScience 41 1402 1407
U.S. Department of Agriculture, Agricultural Marketing Service 1947 United States standard grades for Common Green Onions. Washington, DC
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