Advice on how to keep your onions stored well for the winter.
The most important thing, is to make sure that you are growing the right varieties of onions which store well. Some don't!
'Sturon' - which is available as an onion set as well, together with ‘Hygro’ are two good storing types. you will find many newer varieties in seed catalogues, but these are certain to be ok.
The next most important thing for storing your onions so that they keep well, is how you actually grow them and harvest them. Let the onion leaves die back naturally - do not bend them over as this can cause bruising of the bulb's upper parts.
Dig the onion bulbs out of the soil gently and lay them out to dry in sunshine. You can place them in wooden drying trays instead of leaving them on the soil if you wish. If it is rainy weather, then leave them in place until a few days of sunshine are on offer. They should be dried as quickly and thoroughly as possible. If it turns wet, then take them indoors to finish the drying off.
Take great care when handling them - do not bruise or scratch them as this will cause problems in storage. Onions should be stored in somewhere like a garage - cool but frost free. They can be carefully plaited in ropes and hung up to store, or placed in nets - or old nylons! hand them from the rafters. Alternatively they can be placed in wooden seed trays - single layer - and stored that way.