When to plant shallots

Shallots go in earlier than onion sets. In Germany, Austria and Switzerland plant them from late February to the end of March, as soon as the soil can be worked; in the UK early to mid spring is the usual time.

In mild areas you can also plant in autumn, from late September to early October, using varieties sold as winter-hardy. They root before winter and get a head start in spring. In cold, exposed gardens stick to spring planting.

Some shallot varieties are sold as seed. Sow them like onions: indoors in late winter or outdoors in mid spring, 0.4–0.8 in deep like onion seed. Seed-sown shallots need more time and care than sets.

Choose a sunny spot with free-draining soil and dig in garden compost before planting; that is usually all the feeding shallots need.

Push each set in so that the tip is just level with the surface and its base sits about 1.6–2 in deep. Firm the soil around it. Birds like to tug newly planted sets out by their dry tips, so cover the bed with netting or fleece until the sets have rooted.

Space the sets 6–8 in apart in rows 10–12 in apart. Shallots need the room: each set splits into a cluster of several new bulbs. A 120 × 80 cm raised bed takes three rows of six to eight, 18 to 24 sets.

Shallot leaves cast little shade, so weed regularly and carefully by hand or with a hoe.

Water only in dry spells while the plants are young, and stop once the bulbs have swollen in midsummer, so they ripen and keep well. Autumn-planted shallots can have a light nitrogen feed in late winter.

If a plant sends up a flower stem, cut it off. Bolting is usually set off by cold spells in spring, and those bulbs don't store as well, so eat them first.

Shallots are ready in July, in cooler summers into August, when the foliage turns yellow and flops over. Lift the clusters with a fork on a dry day.

Separate the bulbs and let them dry in the sun or somewhere airy and under cover for about two weeks, until the skins are papery and the necks dry.

Store them in a cool, dry and well-ventilated place, in nets or trays. Well dried, they keep for a long time; the RHS reckons on at least six to eight months. Keep a few of the best, firm bulbs as sets for next year only if the crop was healthy.

Shallots suffer from the same problems as onions. In damp weather, watch for downy mildew (pale patches with a grey-violet fuzz) and neck rot in storage. Onion fly maggots and leek moth caterpillars also attack shallots; fine insect mesh keeps both out.

White rot is the serious one: yellowing, wilting leaves and white fungus with tiny black resting bodies on the base of the bulbs. Those survive in soil for at least 15 years, so plant only healthy stock and never grow alliums where it has appeared. Saving your own sets from a diseased crop spreads it.

Shallots are onions botanically and share the onion family with leeks, garlic and chives. Leave four to five years before any of them grows in the same bed again.

Mixed-planting tables pair shallots with carrots, beetroot, courgettes, lettuce and dill, and keep them away from beans and cabbages. We found no trials behind these pairings; they are tradition. Shallots between carrots won't do any harm.

The rule that matters: don't plant shallots next to or straight after other onion-family crops, because they share pests and diseases.