Check out this site. www.dixondalefarms.com Some onions varieties will keep better than others. Some of the button type sets are mainly for eating as green onions.  We raised a big garden patch of onions this year with some being short day and some intermediate day. We started harvesting ours about the fist of June and finished mid June. We have some starting to go bad now but it gets pretty hot here under a metal building shed where they are stored. We have probably over a 100 LB stored in a cooler that have been there since they got dried down after harvest. I don't know how the refrigerated ones are going to turn out.