Amsterdam, Netherlands · 52.37°
When to plant onions in Amsterdam
The Amsterdam dates are calculated from the observed last spring frost — a 2016–2025 mean of 8 April — rather than from a latitude estimate or a national calendar. The frost-free season here averages 227 days.
Season anchorobserved 2016–2025
Last spring frost: 8 April · latest 28 Apr
First autumn frost: 21 November · earliest 9 Nov
Frost-free season: 227 days · 10 complete years
These come from the ERA5 reanalysis on a roughly 9 km grid, so they describe the area rather than your plot. A hollow, a frost pocket or an exposed site regularly runs several degrees colder, so use the cautious date for a decision you cannot undo.
Frost date estimator →Local calendar windows
The cautious column is calculated from the latest frost recorded in the period (28 Apr). Use it for tender crops you cannot re-sow.
The year in Amsterdam
What can move the date
Plant sets as soon as the soil is workable, tips just showing. Stop watering once the bulbs swell — late water gives soft onions that rot in store.
Final spacing: 10 × 30 cm. Soil: pH 6–7.
Direct-sow only once the soil holds 8°C or more — soil temperature decides germination, not the date.
Problems in Amsterdam
Each has its locally favourable conditions counted month by month, from the weather archive for this city.
Full guide: onions diseases and pests →