Leek in Zone 3a & 3b
Allium ampeloprasum
When to plant leek in zone 3b
Zones 3a and 3b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. Leek needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 21–Mar 28 |
|---|---|
| Direct sow / transplant outside | May 9–May 16 |
| Estimated harvest | Aug 27–Sep 3 (~110 days after transplanting) |
Spacing: 9 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Leeks take their time, 110 days from seed to harvest, but they ask for very little in return once they're in the ground. If you've grown onions or garlic, leeks are the same family playing a longer, more patient game.
How leek fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Leek needs about 110 days from transplant to first harvest.
Good companions
- Carrot: Same allium/carrot pest-masking effect measured for onion and carrot (Uvah & Coaker 1984) — a real, peer-reviewed field study, not folklore.
Where to buy leek seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing leek" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Leek in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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