Science & Nature • Plants

Leek

Leek is a cool-season biennial vegetable in the onion family, grown for its long, blanched edible stalk made from bundled leaf sheaths.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Leek is a cool-season biennial vegetable in the onion family, grown for its long, blanched edible stalk made from bundled leaf sheaths. It has a mild onion-like flavour and is used widely in soups, stews, and other cooked dishes. The plant is usually cultivated as an annual, although it is naturally biennial.

Description

Leeks are a member of the onion family with flat leaves and little bulb development. The edible part is the elongated white stalk formed from overlapping leaf bases, with green leaves also edible.

Cultivation

Leeks are cool-season, frost-tolerant plants usually grown as annuals even though they are biologically biennial. They have a relatively long growing season and are often blanched by excluding light from the lower stem.

Culinary uses

Leeks have a mild, sweet onion flavour and are used in soups, stews, casseroles, pies, and other cooked dishes. They may also be eaten raw, especially in salads.

History and origin

Leeks are an ancient crop, likely domesticated from wild ancestors in the Mediterranean region. Sources place their origin in the eastern Mediterranean, the Middle East, or nearby western Asia.

Key facts

Leeks are related to onions and garlic but do not form a true bulb.
The edible portion is a cylinder of bundled leaf sheaths that is often blanched by mounding soil around the base.
Leeks are generally grown as a biennial plant but harvested after one growing season.
They have been cultivated for centuries and are considered an ancient crop.
Leeks are hardy and frost-tolerant, making them a cool-season crop.

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Canadian context

Leeks are widely available in Canadian grocery stores and home gardens, and Canadian horticulture sources describe them as a cool-season vegetable suitable for growing in local climates.[10][13]

Frequently asked questions

What is a leek?

A leek is a vegetable in the onion family grown for its long, mild-flavoured edible stalk and leaves.

Is a leek a type of onion?

Yes. Leeks are closely related to onions and garlic, but unlike onions they do not form a true bulb.

Which part of the leek is eaten?

The white blanched stalk and the green leaves are both edible, though the white portion is most commonly used.

How are leeks usually cooked?

Leeks are commonly cooked in soups, stews, casseroles, and pies, but they can also be eaten raw.

Where did leeks originate?

Leeks are generally described as native to the eastern Mediterranean and the Middle East, with cultivation spreading from that region.

Are leeks annual or perennial?

Leeks are biennial plants, but they are usually grown and harvested as annual crops.

References

University of Wisconsin–Madison Extension — https://hort.extension.wisc.edu/articles/leeks/
Supports: Scientific name, plant structure, flavour, and origin.
Encyclopaedia Britannica — https://www.britannica.com/plant/leek
Supports: Definition, family, origin, flavour, and culinary uses.
CABI Compendium — https://www.cabidigitallibrary.org/doi/full/10.1079/cabicompendium.4248
Supports: Cool-season habit, biennial nature, and global cultivation.
University of Arkansas Division of Agriculture — https://www.uaex.uada.edu/publications/pdf/FSA-6070.pdf
Supports: Plant morphology, edible parts, and culinary uses.
Washington State Department of Agriculture — https://www.agr.wa.gov/departments/business-and-marketing-support/farm-to-school-toolkit/wa-grown-food-recipe-kit/foodtoolkit/items/vegetables/leeks/facts
Supports: Edible portion, blanching, and nutritional notes.
University of Minnesota Extension — https://www.extension.umn.edu/vegetables/growing-leeks
Supports: Scientific name, growth habit, edible parts, and culinary uses.