Lupine in Zone 4a & 4b
Lupinus spp.
When to plant lupine in zone 4b
Zones 4a and 4b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Lupine doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 1–May 8 |
| Estimated bloom | Jul 20–Jul 27 (~80 days after direct-sowing) |
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 2-4 ft.
Lupine is a nitrogen-fixing legume, but don't expect a quick soil boost from it. That nitrogen only becomes available to other plants once the foliage and roots break down, not while the plant is actively growing. It's grown here mainly for its tall, dense spires of pea-like blooms, and it has a strong climate preference worth knowing before planting: it wants mild summers and struggles badly in low-desert heat.
How lupine fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Lupine needs about 80 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Lupine.
Where to buy lupine seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing lupine" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Lupine in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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