White, red, pink or yellow, onions are lifted at the end of summer and spread out on racks to dry in the sun. Rich in antioxidants and a source of manganese, vitamin B6 and vitamin C, they ask only for a sunny spot and well-drained soil, and will then keep up to six months in a cool, dry place.
There are many onion varieties.
They can keep up to six months in a cool and dry spot.
Onions are not all planted or eaten at the same moment: some go in as the days shorten and are pulled young, others swell through summer for the store cupboard. This table sets out the main groups described below.
| Onion type | When it goes in | When it comes out | What it is for |
|---|---|---|---|
| White or fresh onions | Early autumn | Spring | Eaten fresh, not stored |
| Coloured onions – red, pink, yellow | Late winter to mid-spring | End of summer | Cooking and storing |
| Bunching onions | All year round | As needed | Grown on a windowsill indoors |
| Onions planted as bulbs (sets) | Late winter in mild regions, mid-spring in harsher climates | Late summer to early autumn | Keeping up to six months in a cool, dry spot |
Stagger two or three of these groups and the kitchen is supplied from spring right through to the following winter.
For areas that have a rather mild winter, you can plant onion seeds in the ground directly, forming a line.
It’s also possible to plant bulbs directly, from late winter in mild regions to mid-spring in harsher climates.
Make a small hole or shallow drill for each set rather than pushing it into firm soil, then settle the set in and cover so only the neck tip shows.
Leave enough space between rows to run a hoe down the middle without nicking the swelling bulbs, as onions compete badly with weeds.
Avoid sowing or planting onions on ground that has just been manured, because the excess nitrogen gives soft bulbs that rot in store rather than keeping.
Thinnings pulled from a row of onions or leeks are perfectly edible and can be used like spring onions, though thinnings from other crops should be checked individually before eating.
Onions can thrive in all sorts of soil, as long as they are well drained.
Downy mildew is among the main causes for losing crops.
Onion maggot flies are another enemy.
It is also possible to spray decoctions made from repellent plants such as garlic or absinthe, or set up an insect mesh to send the flies off.
Before harvesting onions for storage in Late summer-early autumn, cut back leaves to ensure that bulbs mature.
When lifting crops for storage, such as onions, garlic, shallots or maincrop potatoes, choose a dry day with dry soil, since damp skins and clinging wet earth encourage rot in store.
Set aside any onion or garlic bulb whose neck stays thick and fails to dry down, or whose skin has split, and use those first, since they tend to store poorly.
Hang the cured onions in nets or plait them into strings so air circulates around every bulb, and pull out any that soften.
In the Alliaceae family, akin to garlic and shallot, onions are everywhere in cooking and boast many medicinal properties. With high antioxidant levels (especially for red onions), they are a source of manganese, vitamin B6 and vitamin C.
Ingesting them on a regular basis is said to protect against cardiovascular diseases and certain cancers.
Laure Hamann
Onions are toxic to dogs and cats, whether raw, cooked or dried.
In onions, quercetin is concentrated in the dry papery skin and the outermost fleshy layers, so peel away no more than you have to if you want to retain it.
Onions are rich in fructans, which is why they are excluded from a low-FODMAP diet and can trouble sensitive digestions.
