When to plant Onions
Calendar windows
Dates shift with your latitude — they are calculated from your local last-spring-frost date, not from a fixed calendar.
At a glance
Takes frost; can go out weeks before the last one.
Practical notes
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.
Knowing when to pick
Wait for the tops to yellow and fold over on their own — never bend them by hand. Lift on a dry day and leave on the surface to dry.
Storing the crop
Cure two weeks somewhere dry and airy, then rope or net them at 0–5°C. Only fully dry necks keep past midwinter.
Crop rotation
Leave 3 years between allium crops — white rot builds up quietly and is permanent.
Grows well with
Keep apart from
Watch for
Full guide: onions diseases and pests (4) → with spread routes, compost verdicts and the prevention this list justifies.