How to Grow Onions and Shallots

How to Grow Onions and Shallots

Allium species

Although there are many different types of onion, not all lend themselves to cultivation in the small garden. Red varieties are available and are most attractive in dishes requiring raw onion. Two types of onion and the closely related shallot will fulfil most of the usual onion needs.

Learning how to grow onions is not difficult – the common bulbous onion, Allium cepa, is grown from ‘sets’ (small bulbs) or seed sown in spring; to extend the cropping season you can also use the autumn-sown Japanese varieties. The shallot, a variety of Allium cepa aggregatum, is prolific and a true all-rounder; although small the bulbs may be used in cooking in the same way as the larger common onions, or they may be used as spring onions or for pickling. These two types may be supplemented by growing onions of another species specifically for salads. A good choice would be the Japanese bunching onion, Allium fistulosum, also known as onion leeks. 

Common Onion

how to grow onions Sow thinly at a depth of 12-20 mm (½-¾ in) in rows 300 mm (12 in) apart from mid-April or from early to mid-autumn depending on variety. Thin the spring-sown onions gradually until the remaining plants are 40-150 mm (11/2-6 in) apart. Thin autumn-sown varieties in the spring, using the lifted ones as spring onions.

When you are growing onions, sown onions require soil well enriched with compost dug in a month or two previously and allowed to settle. A sunny site is preferable.

In damper and colder areas, and if raising plants from seed proves difficult, use onion sets instead of seed. Ask for heat-treated sets if you are buying them. The sets are planted in the main plot on ground that was well composted for a previous crop. Space the sets 50-150 mm (2-6 in) apart in rows 250 mm (10 in) apart or in blocks. Cover the sets lightly with soil, firm them in, and water. To prevent the plants from bolting the soil should be moist (but not too wet) at all times. Keep the soil free of weeds.

how to grow onions When the crop is approaching maturity, bend the tops over just above the bulbs to allow the maximum sunshine for ripening. The leaves will gradually yellow and dry, and the bulbs should then be gently lifted with a fork and laid on the surface to dry out. (In a wet season however, it may be necessary to dry them off under cover on racks of wire netting.)

On dry soils the commonest pest is the onion fly. The bulbs are attacked by the fly maggots and become mushy and rot; if this happens dig up the affected bulbs and burn them. The pest will be deterred to some extent if you sprinkle calomel dust into the soil when sowing or planting, and by spraying the plants with one of the trichlorphon insecticides every few weeks during growth.

Unless you are using the onions immediately after lifting, those harvested in autumn can be hung in ‘ropes’ or nets in a dry, frost-free place. The autumn-sown, summer-lifted types are not good keepers and should be used as soon as possible after harvesting.

Recommended varieties:

SEED: (spring-sown for autumn harvesting) ‘Ailsa Craig’, popular, large (use maximum spacing); ‘Bedfordshire Champion’, good keeper; ‘Brunswick’ (‘Blood Red’), red variety, good keeper; ‘Hygro’, excellent keeper; ‘Rijnsburger’ selections; ‘Southport Red Globe’, attractive red variety

SEED: (autumn-sown for summer harvesting) ‘Express Yellow O-X’; ‘Imai Early Yellow’; ‘Senshyu Semi-Globe Yellow’

SETS: (spring-sown for autumn harvesting) ‘Brunswick’ (‘Blood Red’); ‘Giant Fen Globe’; ‘Rijnsburger-Wijbo’; ‘Sturon’; ‘Stuttgart Giant’ 


Plant as for onion sets, at intervals of 150 mm (6 in) in rows 100 mm (4 in) apart. Harvest as ‘spring onions’ when required, either by gently breaking individuals off the growing clumps or by lifting whole clumps. Mature bulb clumps are lifted, separated, dried, and stored as for onions; they are good keepers.

Most seedsmen sell reliable varieties with either yellowish brown or reddish brown skins.


Hoe lightly between the rows to keep down weeds. About the third week of June, if the weather has been dry, give the plants a feed of Liquinure or Bio Humus, at the rate of up to a pint per plant after dilution according to the manufacturer’s instructions.


Fourteen days after the leaves start to turn yellow, the clusters of bulbs which will have developed should be lifted by inserting a fork underneath the clusters and pressing the handle down carefully; leave the bulbs on the surface of the soil. A week later put the clusters of bulbs on a path or the tin roof of a shed to continue ripening and turn them slightly every day. After a week of this treatment divide the clusters into separate bulbs. They can then be stored or used.


Common Shallot, small, brown English variety.

Russian Shallot, a much larger bulb. Reddish-purple in colour.

Japanese Bunching Onion

These provide, if sown successionally, an almost continuous supply of long spring onions. Sow in soil and site similar to those for common onions, or as an intercrop. August sowings provide spring crops; late-winter and early-summer sowings are harvested, respectively, in summer and autumn. Sow to a depth of 6 mm (¼ in) in rows 200-250 mm (8-10 in) apart. Harvest as required seven to nine weeks after sowing, or longer in poor weather.

Recommended varieties: ‘Hikari’; ‘Ishikuro’; ‘Kincho’; ‘Long White Tokyo’

Site: Sunny

Soil: Good

Sow: Spring or autumn according to variety; plant sets in spring

Harvest: As required according to variety

19. October 2010 by Dave Pinkney
Categories: Fruit & Veg, Kitchen Garden | Tags: , , , , , | Comments Off on How to Grow Onions and Shallots


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