When to plant Spring Onions in the UK

Allium cepa

Spring Onion
Spring Onion · Allium cepa

Spring onions are a fast salad onion for the UK garden. Sow little and often through spring and summer, or sow a winter-hardy variety to pick next spring. They take little space and grow well in pots.

30 cm · Full Sun · Moderate Water

Add to garden
Sow outdoors March to August, harvest May to October.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Sow outdoorsNoNoYesYesYesYesYesYesNoNoNoNo
HarvestNoNoNoNoYesYesYesYesYesYesNoNo

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.

Sow small batches outdoors for salad onions through spring and summer.

  1. 01

    Sow Seeds Outdoors

    late March to late August UK average · set your town for your exact dates Optional · repeat every 2 weeks

    Sow thinly around late March to late August, deep. Sow a fresh batch every 14 days. Keep the seedbed moist.

    • Slugs go for young seedlings. Check the row after rain.
    • A cloche helps the first sowing of the year if nights are still cold.

  2. 02

    Thin Seedlings

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

    After each sowing, once seedlings are a few centimetres tall, thin to apart. Lift the extras gently so you do not disturb the plants you keep. Use them in the kitchen. Do not leave them on the soil, or onion fly finds the row.

  3. 03

    Water regularly

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

    After each sowing, water well until the plants are established. After that, water in dry spells.

  4. 04

    Harvest

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

    After each sowing, pull plants from late May once they are pencil-thick and about tall. Keep picking through late October. Use them fresh. They do not store well.

Companion plants

Tap a plant to see why it works (or doesn't) with Spring Onion.

Good companions

Plants to avoid

Why companion planting matters

Companion planting can deter pests, improve pollination, and make better use of space. Some plants confuse pests or attract beneficial insects; others improve soil or offer shade to neighbours that need it.