Growing Onions from Sets


Onions are especially easy to grow if grown from onion sets.  A set is a baby onion.

You could choose to grow versatile white onions, sweet red onions for salads or shallots to store for winter stews.



Choose a sunny site.  Ideally the soil will have had some organic matter added the previous autumn.  It is important to follow a crop rotation plan and not plant onions or leeks (leeks are in the onion family) in the same ground each year.  Onion pests and diseases can persist in the soil.

The soil will be ready between mid-March and mid-April; it must not be soggy or cold.  If the grass had started growing it is likely that the soil will be warm enough.  If the spring is looking cold or very wet you can start your onion sets off in large-holed modular trays and then carefully transplant when the conditions improve.

Prepare the ground by raking until it is even and friable; add Westland organic Potato and Vegetable Fertiliser. Plant in rows 30cm (12”) apart and space the sets 10cm (4”) apart.  Gently push the sets into the soft earth, just leaving the tip of the set protruding.

Autumn Onion Sets.  A few varieties are available as sets to be planted in the autumn.  They are worth trying as well as spring sets as you can get a slightly earlier crop.


Keep an eye on the sets for the first few weeks as sometimes birds can pull them out of the ground and you have to replant them.

Weeding is important around an onion crop.  An onion hoe is a small hand held hoe designed for this job.  When weeding be careful not to catch the onions as onion flies are attracted by the scent.

Tip – plant onions and carrots together.  The smell of the carrots deters the onion fly and the smell of the onions deters the carrot fly.  Win-win.


Once the foliage starts to yellow and crook over you must stop watering your onions.  It is a good idea to gently lift them and lay in the sun to thoroughly dry before storage.

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