onion

Allium cepa

Amaryllidaceae · bulb · introduced

Last updated

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

On Puget Sound clay soils, amend heavily with compost or grow in raised beds. Long-day types preferred at this latitude. Walla Walla sweet onion is the iconic PNW variety.

— Claude / Chris Welch

Quick Facts

Height
1-2 ft (foliage); 3-4 ft (flower scape)
Spread
0.5-1 ft
Growth Rate
Moderate
Light
Full Sun
Soil
Well Drained
Water
Moderate
Hardiness
Zone Zones 3–10
Bloom Time
June-July (second year if bolting)
Origin
Central Asia (likely Iran/Afghanistan region)

Diseases (3)

Botrytis Blight (Gray Mold) Peronospora sparsa Downy Mildew Stromatinia cepivora (syn. Sclerotium cepivorum) White Rot

Pests (2)

Cultivars (2)

''Walla Walla''
Long-day sweet onion. Very mild flavor; large bulbs. Poor storage life (1-2 months). The iconic PNW onion.
Transplant in early spring for summer harvest
''Copra''
Long-day storage onion. Firm, pungent, excellent keeper (6+ months).