When to plant Spring Onions in Perth

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

Calibrated to Perth · last frost ≈ 9 May

Sow outdoors April to August, harvest June to October. Frost risk October to May.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Sow outdoorsNoNoNoYesYesYesYesYesNoNoNoNo
HarvestNoNoNoNoNoYesYesYesYesYesNoNo

Growing guide

What to do through the growing season

Growing guide for

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

    4 Apr to 10 Aug Optional · repeat every 2 weeks

    Sow thinly around 4th April - 10th 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

    25 Apr to 9 Oct 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

    4 Apr to 9 Oct 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

    3 Jun to 9 Oct Dates as each sowing reaches this stage

    After each sowing, pull plants from 3rd June once they are pencil-thick and about tall. Keep picking through 9th 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.

Spring Onion guides by town

See how Spring Onion timing shifts in other towns with different frost dates.