Sea Kale in Zone 4a & 4b

Crambe maritima

When to plant sea kale 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. Sea Kale doesn't transplant well, or doesn't need the extra time indoors.

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 4's season

Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. 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 4b 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

• Botanical Interests
• True Leaf Market
• Burpee
• High Mowing Organic 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 4b 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 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.

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