Care & Cultivation of Onion Sets, Shallots & Garlic

In your onion sets you may notice that some feel slightly soft and/or have started to grow a little this is quite natural and should not affect their performance. To keep bulbs until planting time, spread them out in a tray and place this in full light in a cool, dry and well-ventilated place. Check them regularly to ensure they are in good condition.


Fertile ground, which has been manured, but not freshly, is ideal. Lime if your soil is acid. Autumn planting sets can be put in at any time between September and November, as long as weather and soil conditions are suitable, but for the largest bulbs it is best to plant as soon as ground can be made ready. Autumn-planting garlic should be planted in October or November. Do not grow any of these bulbs on land that may become waterlogged in winter. Spring-planting onion sets can go in at any time between early March and mid April. The ground should not be frozen or too wet, but heat-treated sets should not be planted until early April. Normal shallots should be put in between mid-December and the end of March, but delay planting variety ‘Sante’ until mid-April. Plant spring-planting garlic any time there is mild weather in late winter or early spring, but preferably by early March as this crop requires a long growing season. You can start your garlic off in cell modules in late autumn. Overwinter in an unheated greenhouse or cold frame and plant out as soon as soil is workable in spring. Just before planting garlic supplied as bulbs, carefully prise the individual cloves from within each larger bulb, avoiding any damage. Plant flat end down – pointed end up. Plant sets or cloves in shallow drills or use a trowel. When you have finished planting onions and shallots the tips should be only just protruding. If you plant too shallow the birds are likely to pull them out before they’ve rooted. Garlic should be planted at least 5cm (2in) deep or twice the depth of each clove, on light soils they can be panted up to 10cm (4in) deep.


  • Onions in rows 25cm (10 inches) apart.
  • For medium sized onions, space the sets 10cm apart in the row; a larger gap of 15cm (6in) will give larger bulbs.
  • Shallots in rows 25cm (10 inches) apart, with 15cm (6 inches) between bulbs.
  • Garlic in rows 30cm (12in) apart, with 13-15cm (5-6 inches) between cloves.


Check the sets regularly to make sure none have been pulled out. If they have it is best to remove and
replant as just pushing them back can break off the young roots and encourage rot.
DO NOT over-water especially when they are maturing in late spring and summer.
All information is believed to be correct and is provided as advice for members new to growing these crops. © BRAA

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