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Onion: when to sow, plant out and harvest

Sowing, planting and harvest dates for your climate, good and bad companions, growing tips.

When to sow in your region

Average dates, computed from the frost dates of each climate. For your exact dates, choose your town.

ClimateSow under coverSow outdoorsPlant outHarvest
Northern France4 February – 24 February18 March – 7 April; 29 September – 19 October18 March – 7 April; 1 October – 30 November1 April – 30 September
Atlantic coast25 January – 14 February8 March – 28 March; 3 October – 23 October8 March – 28 March; 5 October – 4 December22 March – 4 October
Eastern France27 January – 16 February10 March – 30 March; 27 September – 17 October10 March – 30 March; 29 September – 28 November24 March – 28 September
Mediterranean24 December – 13 January4 February – 24 February; 19 October – 8 November4 February – 24 February; 21 October – 20 December18 February – 20 October
Mountains (around 1,000 m)1 March – 21 March12 April – 2 May; 28 August – 17 September12 April – 2 May; 30 August – 29 October26 April – 29 August

Growing

Family
Amaryllidaceae
Latin name
Allium cepa
Cold tolerance
Hardy (withstands frost)
Soil temperature to germinate
2 °C minimum
Emergence
7–12 days
Between rows
20–30 cm
In the row
10–15 cm
To harvest
110 days

Companion planting

The level of evidence is shown for each pairing: many rest on tradition rather than on studies.

Good neighbours

Keep apart

Sources