When to plant Spring Onion in Temperate Australia

Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Tropical · Cool · Subtropical · Arid.

Two windows suit spring onions in temperate Australia: sow direct in March and April, or from September through to December. The seed goes 10 mm deep, germinates in 7–14 days, and stems reach pulling size in 60–70 days — one of the quicker rewards in the onion family. Unlike bulbing onions there's no fussing over day length; spring onions (Allium fistulosum) simply grow straight, slender stems whenever conditions aren't extreme. Sow them close, 5–10 cm apart, tuck rows between slower crops, and re-sow every few weeks within each window for a continuous supply.

Sowing calendar — temperate zone

Green months are your sowing window: March to April and September to December.

Growing notes

Spring onions are hardy, so a March or April sowing stands through temperate winter frosts without protection — growth slows right down through the cold, then the crop comes good as spring arrives. Sowings in the September–December window move much faster in warming soil and hit the 60–70 day mark reliably.

Succession is the trick with this crop. Rather than one long row that all matures at once, sow a short row every three or four weeks inside each window; a metre of row at a time keeps a kitchen supplied without waste.

Any reasonable free-draining soil will do, with a little compost worked in beforehand. The roots are shallow, so regular light watering suits them better than occasional flooding, and they sulk in waterlogged ground. Weeds are the real enemy — thin, upright seedlings shade out nothing, so a weedy bed swallows the crop whole. Keep on top of it while plants are small.

The most common failure is sowing too thickly and never thinning, which produces a matted, grass-like tangle of stems too skinny to bother with. Thin early to 5–10 cm apart with rows 20–30 cm apart, and eat the thinnings — they're perfectly good at any size.

Spring Onion at a glance

Companion planting

Grows well with

Carrot: Scent deters carrot fly

Keep away from

Bean (Bush): Alliums inhibit legume growth

Common questions

When can I plant spring onions in Australia?

In temperate zones there are two direct-sowing windows: March to April, and September to December. Sow 10 mm deep and expect seedlings within 7–14 days.

How long do spring onions take to grow?

About 60–70 days from sowing to pulling size, after germinating in 7–14 days. Sowing a short row every few weeks keeps the supply continuous.

Do spring onions grow through winter in Australia?

Autumn sowings made in March or April are hardy enough to stand through temperate frosts. Growth slows over winter, then picks up again in early spring.

Why are my spring onions so thin and tangled?

Sowing too thickly without thinning is the usual cause. Thin seedlings early to 5–10 cm apart and keep the bed weeded — crowded or weedy rows produce skinny stems.

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