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Planting onions sets

Growing onions from sets is generally easier and the crop will mature earlier than if grown from seeds. As onion sets grow they form a larger bulb.

Piroska red onionPlant onion sets in early to mid-spring about 2cm (¾in) deep and 5-10cm (2-4in) apart leaving 25-30cm (10in-1ft) between the rows. Plant in drills or merely push the sets into loose earth. Only the tips of sets should show. Covering with fleece helps to prevent birds uprooting the sets. Remove the fleece once the plants have established in the soil.

Planting shallot sets

shallotsPlant shallot sets about 2.5cm (1in) deep and 15-20cm (6-8in) apart in rows 30-45cm (1ft-18in) apart. Only the tips of the bulbs should show.

As shallot sets grow the sets split, forming a clump of bulbs.

Planting garlic cloves

After planting, garlic needs a cool, one- to two-month period at temperatures of 0-10°C (32-50°F) for good bulb development. Planting in early spring will provide the necessary chilling period.

Garlic is planted from bulb segments (cloves), so break up the bulb carefully into individual segments prior to planting. Make sure that the cloves of garlic are planted the right way up: the flatter basal plate should be facing downwards.

Allow 15cm (6in) between individual garlic cloves and 30cm (1ft) between rows. Plant the cloves so the tips are 2.5cm (1in) below soil surface

Deeper planting can encourage better yields on light soils, but do not plant deeply on heavy soils.


The crop can be easily swamped by weeds, which would negatively affect the plants’ growth and subsequent yields. Hand weed regularly. Hoeing with an onion hoe can be tricky as the foliage and top of the bulb can be easily damaged. Alternatively, consider planting through black plastic sheeting to suppress weeds.

Water every fortnight during prolonged spells of dry weather until mid-summer. Watering of spring-planted or spring-sown crops after mid-summer can reduce the storage quality.

Harvesting onions

OnionsSpring-planted onions are harvested in late summer to early autumn. Yellowing and toppling of the foliage is a sign that the crop is getting ready for harvest, but lift the bulbs before the foliage dies down completely.

Carefully lift the onions with fork avoiding bruising that could later lead to rotting in storage.

Harvesting shallots

Shallots usually ripen in mid- to late summer. Lift shallots in bunches and then carefully separate.

Harvesting garlic bulbs

Harvest spring-planted garlic from mid-summer to early autumn.

Lift the garlic bulbs with a fork once the foliage starts to fade and go yellow. Avoid bruising the bulbs as it reduces their storage quality. Dry them off thoroughly in a single layer in the sun or in a dry, well-ventilated place such as a shed. Store in a dry place at 5-10°C (41-50°F).


Spring planted onions, shallots and garlic can last until well into the following season if stored correctly.

Place the onion/shallot bulbs in a single layer on a drying rack made from chicken wire or use slatted crates placed upside-down. Ripen the onion/shallot bulbs in full sun outdoors for about two weeks or in a greenhouse or well-ventilated shed if the weather turns wet.

Onions can be tied onto strings or stored in an onion bag.

Garlic bulbs can be tied into plaits, store in net bags or in trays in a single layer. Store garlic in light, cool, dry and well-ventilated place. Storing in the dark encourages sprouting.