Spring Onions in Penmachno

Allium cepa

Spring Onion
Spring Onion · Allium cepa

Spring onions are fast-growing, mild-flavoured onions grown for their green stems and small bulbs. They are easy to grow and can be sown in succession for a continuous harvest. Hardy varieties can even be sown in late autumn to overwinter for an early spring crop. Spring onions don't take much space and grow well in containers or between slower-growing vegetables.

30 cm · Full Sun · Moderate Water

Add to garden

Calibrated to Penmachno · last frost ≈ 13 May

Sow April to August, harvest July to October. Frost risk October to May.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
SowNoNoNoYesYesYesYesYesNoNoNoNo
HarvestNoNoNoNoNoNoYesYesYesYesNoNo

Growing guide

Step-by-step instructions for growing Spring Onion

Growing guide for

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Step-by-step guide to growing spring onions sown outdoors in spring and summer.

  1. 01

    Sow Seeds Outdoors

    8 Apr to 1 Aug

    April to August is the main period to sow spring onions in Penmachno. Sow seeds in rows about apart and deep. Keep the soil moist and weed-free. For a continuous supply, sow new batches every few weeks.

  2. 02

    Thin Seedlings

    5 May to 14 Jul

    Once seedlings are a few centimetres tall, thin them to about apart. Remove the weaker ones carefully to avoid disturbing the remaining plants. Thinning gives each spring onion space to grow to a good size.

  3. 04

    Harvest

    10 Jul to 7 Oct

    Spring onions are usually ready to harvest about 90 days after sowing. Pull them up once they reach pencil thickness. Harvesting can start from July and continue until October for later sowings. Spring onions are best used fresh, as they do not store for long.

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.