Sea Kale in Zone 6a & 6b
Crambe maritima
When to plant sea kale in zone 6b
Zones 6a and 6b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Sea Kale doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Apr 11–Apr 18 |
| Estimated harvest | Apr 10 '29–Apr 17 '29 (First real harvest in year 3) |
Spacing: about 4 square feet per plant (square-foot-gardening spacing). Mature height: 1.5-2.5 ft.
Sea kale is a Brassica-family perennial from European seashores that was a popular Victorian-era vegetable and has never quite managed a comeback since, despite being easy to grow in much of the US outside hot, humid summers.
How sea kale fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Sea Kale takes about 2 growing seasons to reach first worthwhile harvest, so what matters here is how many of these seasons it gets, not whether one is long enough.
Sea Kale is hardy in zones 4-8, so in zone 6b it stays in the ground through winter and comes back rather than being replanted. Allow about 3 ft of spread at maturity.
Good companions
No standout companions recorded yet for Sea Kale.
Where to buy sea kale seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing sea kale" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 6b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Sea Kale in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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