Vegetables/Easy
Onions
Allium cepa
Onions are one of the easiest crops if you start from 'sets' — small, dormant bulbs pushed just into the soil with their tips showing. They ask for very little through the season and reward you with the backbone of a year's cooking.
The most common mistake is watering right up to harvest. Once the tops start yellowing and flopping in mid to late summer, stop watering and let the bulbs cure. Lift on a dry day, dry the necks in the sun for a week, and store somewhere cool and airy.
Year at a glance
Common problems
Rotting bulbs in storage
Necks were not fully dry. Cure for 7–10 days in dry, airy conditions before storing.
Bolting to flower
Cold shock after planting. Use heat-treated sets in cool springs, and plant when soil is above 6°C.
White rot at the base
Soil-borne fungus. Rotate alliums to a new bed for at least 4 years and destroy affected plants.
Questions, answered
Should I fold over the tops of onions?+
No — let them flop naturally. Bending the necks by hand damages the bulb and shortens storage life.
When do I stop watering onions?+
As soon as the tops start yellowing and toppling — usually 2–3 weeks before harvest.
How long do stored onions last?+
Well-cured onions keep 4–6 months in a cool, dry, dark place. Discard any showing soft spots.