Old, means should know better but never managed it.
Technically, you should pull the onions up, let them lay on the soil and they will produce thin skins on the outside while the sun(Ha Bxxxxy Ha) dries them. Then you should hang them in a dry, airy place and use them when you want to. This actually works given proper weather. In practice, I pull them and then hang them in a dry airy place. They should last for the winter. Actually I expected a bit more "pro" advice from allotment holders, sorry, you've just got me!
