Dry onions for store once the tops turn brown and start dying back - a sure sign they've done their growing and are ready for digging up and storing for winter.
Onions store brilliantly for several months if they're dried well, so it's worth taking your time. The idea is to dry just the top layer of brown skin to a crisp, hard coating which preserves the core of the bulb in suspended animation, protected from mould and premature sprouting.
Start by just loosening off the roots with a fork but leaving the onions in the ground for a couple of days. This breaks the link with the ground and starts the roots drying off. Then lift the onions completely: if the weather is sunny, you can lay them straight on the soil to dry naturally, but if it's damp take them inside somewhere – a greenhouse is ideal. Separate out any damaged onions and eat straight away – they'll only turn mouldy if you try to store them.
Turn them every two to three days and let them dry slowly over about a week. Then trim away the roots and plait them onto strings to hang on a hook in the kitchen until needed.
