The onion (Allium cepa) is a biennial grown as an annual for its swollen bulb, the most widely cultivated Allium species. Grow it in full sun with steady moisture and well-drained soil, and harvest when the leaves die back in autumn.
Family
Amaryllidaceae (Daffodil & onion family)
Grows as
Tree, Bulb
Light
Full sun
Water
Water regularly and evenly, and ease off as the bulbs mature and the leaves begin to yellow.
Soil
Loose, fertile, well-drained loam with good organic matter.
Temperature
13–24 °C is ideal; hardy to about -10 °C in many varieties, but protect young plants from hard frost.
How easy
Easy
Safety
Not known to be toxic: Not known to be toxic to people when eaten; the bulb and leaves can cause contact dermatitis, itching, and rarely anaphylaxis in sensitive people, especially when handled raw.. Toxic to cats and dogs (ASPCA).
Edible
Yes, some parts
Native range
as a cultigen from C. Asia
Climate
temperate
About
The onion (Allium cepa L.Tooltip Carl Linnaeus, from Latin cepa), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus Allium. The shallot is a botanical variety of the onion which was classified as a separate species until 2011. The onion's close relatives include garlic, scallion, leek, and chives.
The genus contains several other species
Safety
Some people suffer from allergic reactions after handling onions. Symptoms can include contact dermatitis, intense itching, rhinoconjunctivitis, blurred vision, bronchial asthma, sweating, and anaphylaxis. Allergic reactions may not occur when eating cooked onions, possibly due to the denaturing of the proteins from cooking.
Text excerpted from the Wikipedia article Onion by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.