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 August to October, harvest June to September.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Plant outNoNoNoNoNoNoNoYesYesYesNoNo
HarvestNoNoNoNoNoYesYesYesYesNoNoNo

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 named overwintering sets in free-draining soil for an earlier crop. Do not use spring sets.

  1. 01

    Prepare the Bed

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

    Prepare the bed around mid-August to late August. It must drain freely. Work in garden compost or well-rotted organic matter. Do not add fresh manure.

  2. 02

    Plant Overwintering Sets

    late August to early October UK average · set your town for your exact dates

    Plant named overwintering sets around late August to early October, tips just showing. Do not plant spring sets. Space apart, in rows apart. Firm the soil. Water if it is dry.

    • In a mild town, wait until the soil is cooling. Too much autumn leaf can raise the risk of bolting in spring.
    • Birds lift sets. Cover with fleece or mesh until they root.

  3. 03

    Keep Weed Free

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

    From late August to late May, keep weeds down. Hand-weed close to the bulbs. Water in dry spells once growth restarts, then ease off when the leaves begin to yellow.

  4. 04

    Lift and Cure Bulbs

    early June to early September UK average · set your town for your exact dates Dates as each sowing reaches this stage

    Lift bulbs through early June to early September, 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.