Leek is a perennial grown for the harvest, ready about 100 days after sowing. It's hardy across USDA zones 2 through 11 and stands up to deer. Its flowers are a moderate draw for honeybees, native bees, and butterflies, even though the harvest is the prize. As an allium (the onion family), give it a fresh bed each year — away from where its relatives just grew — so the soil-borne pests and diseases of the family never get a foothold.
Leek — the short answer
Leek: grown in zones 2–11, full sun, pH 4.5–7.5, about 100 days to maturity.
- USDA zones
- 2–11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Soil pH
- 4.5–7.5
- FAO ECOCROP
- Sun
- Full Sun
- Growable Ground Plant Database
- Days to Maturity
- 100 days
- UMass-Veg; OSU-PNW
- Frost-kill temperature
- 23°F
- FAO ECOCROP
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.
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What Leek is
Leek grows as a perennial and reaches around 2.5 feet at maturity. It's also deer-resistant.
How to grow Leek
Leek grows in USDA zones 2 through 11 and is ready to harvest about 100 days after planting. Leek does best in full sun — at least 6 hours of direct sun a day — and soil from pH 4.5 to 7.5, on well-drained ground. It needs around 1,500 growing degree days to mature and a growing season of at least 120 frost-free days, which is why climate matters as much as soil.
USDA Zones
2-11
USDA PHZM 2023
Soil pH
4.5 - 7.5
FAO ECOCROP
Sun
Full Sun
Growable Ground plant catalog
Drainage
well (dry spells)
Growable Ground plant catalog
Frost Kill Temperature
23°F
Where cold starts killing growing tissue. Not a winter-survival floor — a dormant perennial takes far colder, which its hardiness zone answers.
FAO ECOCROP
Minimum Growing Temperature
42.8°F
Below this it stops growing rather than dies — a pace limit, not a survival limit.
FAO ECOCROP
Days to Maturity
100 days
Leek; from transplant.
UMass-Veg; OSU-PNW
GDD Required
1500+
Growing degree-days of accumulated warmth it needs to mature — humid summers reach this faster than cool coastal ones.
Growable Ground plant catalog
Mature Height
2.5 ft
Growable Ground plant catalog
Frost-Free Days
120+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
Start the season right
Plant leek in full sun with at least 6 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Leek prefers pH 4.5 to 7.5 (FAO ECOCROP). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at maturity
Leek is ready about 100 days after sowing (UMass-Veg; OSU-PNW). Watch for cultivar-specific ripeness cues and pick at peak.
Where Leek thrives
On hardiness alone, leek grows across most of the country — its range (USDA zones 2 through 11) is unusually wide. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 2–11 spans average winter lows from -50°F to 50°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 48 outright and splits 3 more down the middle — and which side of that line your land sits on changes the answer.
Two different numbers hide in that range: zones 2–11 is where leek is GROWN, but it survives winter in the ground only down to zone 5 (NC State Extension Gardener Plant Toolbox; Missouri Botanical Garden Plant Finder). Colder than that, it is grown as an annual or brought under cover.
Zones 2–11·Where Leek growsOpen map →
Continental US shown — Alaska and US Pacific territories sit outside the federal map's polygon dataset.
Where Leek stands, state by state
Leek is rated for zones 2–11 — a cold floor USDA puts at -50 to -40°F. Across the 50 states and DC, 48 sit fully inside that band, the line runs through 3 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 2–11
48 states
3 of 48 shown
State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.
What grows around Leek
Growing guides for leek
In rotation planning, leek counts as a Allium — beds recover best when allium crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)
Related plants in vegetable
Good to know
One caution for pet owners — leek is toxic to dogs and cats (moderate severity). Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)
Leek offers moderate value to bees and other pollinators. (Source: Pollinator Partnership.)
Before you harvest leek, know your soil
Anything you grow to eat takes up what's in the ground it grows in, so it's worth knowing what's documented near you before you plant leek for food. Our free screen reads 9 federal source types across roughly 1.8M indexed sites and shows which sit near your address and which way they drain. It's a screening estimate from public records and proximity — not a soil test — so a nearby record means a soil test is worth it, not that your soil is unsafe.
Your land is one point inside Leek's range
This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.
See if Leek will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether leek actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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How we know this about Leek
The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.
Grounded inUSDA PLANTS Database•USDA PHZM•ASPCA
Frequently asked questions
Can I grow Leek in my zone?
Leek grows in USDA hardiness zones 2 through 11 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
How long does Leek take to grow?
Leek is ready to harvest about 100 days after planting (UMass-Veg; OSU-PNW). Your local frost dates and soil temperature move that window earlier or later.
When should you plant Leek?
Most growers plant leek after the last spring frost, once the soil has warmed, leaving enough of the season for its 120-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Leek need?
Leek needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.
What soil does Leek need?
Leek prefers soil pH 4.5 to 7.5, on well-drained ground (FAO ECOCROP). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Leek attract pollinators?
Yes — leek's flowers are a solid nectar source for honeybees, native bees, and butterflies. (Source: Pollinator Partnership.)
Is Leek safe for pets?
Leek is toxic to pets (dogs,cats) with moderate severity. Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)