When to plant Onions in the UK

Allium cepa

Onion
Onion · Allium cepa

A hardy allium for UK gardens, grown from sets. Plant spring sets for a summer crop, or named overwintering sets in autumn for an earlier lift. It needs free-draining soil, steady weeding, and a careful cure before storing.

45 cm · Full Sun · Moderate Water

Add to garden
Plant out March to April, harvest August to October.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Plant outNoNoYesYesNoNoNoNoNoNoNoNo
HarvestNoNoNoNoNoNoNoYesYesYesNoNo

UK averages · set your town for dates worked out from your local frost records · how dates are worked out

Growing guide

What to do through the growing season

Dates for your town

Set your town to see planting windows worked out from local frost history, not a generic UK calendar.

Growing guide for the UK

Change the guide to see different planting timelines and tips.

Plant spring sets for the simplest summer crop. This suits a sunny, free-draining bed.

  1. 01

    Prepare the Bed

    mid-March to early April UK average · set your town for your exact dates

    Work the soil from mid-March to early April. It must drain freely and have a fine tilth. Mix in compost or well-rotted manure. Do not add fresh manure.

  2. 02

    Plant Sets

    late March to mid-April UK average · set your town for your exact dates

    Plant spring sets from late March to mid-April, tips just showing. Space apart, in rows apart. Water in well.

    • Birds lift sets. Cover with fleece or mesh until they root.

  3. 03

    Keep Weed Free

    late March to mid-August UK average · set your town for your exact dates Dates as each sowing reaches this stage

    From late March to mid-August, keep weeds down. Hand-weed close to the bulbs. Water in dry spells while the bulbs are swelling. Keep the soil moist, not soggy.

  4. 04

    Lift and Cure Bulbs

    mid-August to early October UK average · set your town for your exact dates Dates as each sowing reaches this stage

    Lift bulbs through mid-August to early October, when the tops yellow and fall over. Dry them somewhere warm and airy for two to three weeks, then trim the roots and loose tops before storing.

Suggested varieties

Popular varieties of Onion to consider

Sturon

A dependable maincrop onion with good storage qualities and firm, globe-shaped bulbs.

Red Baron

A reliable red onion with good colour and a steady crop from sets or transplants.

Senshyu Yellow

A well-known overwintering onion that can be planted in autumn for an early summer harvest in mild UK gardens.

Centurion

A widely grown, high-yielding set onion with good tolerance to bolting.