Growing Guides How to grow onions

Date Published:

15/10/2007

Sowing

Prepare the soil as above and use your pegs and string to mark out a row.

Make a narrow furrow along it using the corner of a hoe or rake. Sow the seed thinly and cover it lightly (with no more than ½cm (¼in) of soil).

Once they have pushed through, remove weaker seedlings to leave stronger specimens about 2½–5cm (1–2in) apart.

If you sow seed every three weeks from spring to summer, you'll be rewarded with a continuous crop through to autumn.

Some varieties (check the packet) can be planted a little later and covered with a cloche (a glass or polythene cover that most garden centres will stock) for picking in early spring.

Planting

The easiest and quickest way to raise onions is by using sets - partly developed baby onions - rather than seed.

They are less demanding, grow rapidly and tend to give more consistent results (the downsides being that they are more expensive and the choice of varieties is much more limited).

They are usually planted from early to mid-spring for a midsummer crop, except hardier Japanese varieties which can be started off in autumn to be ready the following year.

Onions prefer a sunny position and will always do best in a rich soil.

Dig it over, to a depth of around 45cm (18in), working in some well-rotted garden compost and removing any stones that you come across.

Just before planting, tread the soil down firmly. You should prepare the beds well in advance of planting or sowing, ideally around three months before.

Use your pegs and string to mark out a row. Plant the sets along it by digging small holes in the soil with a trowel. Place one set in each hole with the pointed end uppermost.

They should be spaced between 10 and 15cm (4–6in) apart. Leave 30–45cm (1ft–1ft 6in) between rows.