Sea Kale
Crambe maritima
vegetableSea kale (Crambe maritima) is a robust, long-lived herbaceous perennial of European sea coasts, forming a handsome clump of large, lobed, wavy-edged, powder-blue leaves about 30 to 36 in tall and wide, topped in early summer by fragrant clouds of small white flowers. It is grown chiefly for its blanched spring shoots, forced in darkness under a pot and cut like asparagus, with a sweet, nutty, mild-cabbage flavor. Exceptionally hardy and tolerant of salt, wind, and lean sandy soil, an established plant can crop for many years.
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Sun
full sun
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Water
Every 6 days
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Harvest
~3 yrs
to first harvest
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Difficulty
medium
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Lifecycle
perennial
Comes back every year
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Spacing
24-30 in apart
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Planting Depth
Set crowns with the bud just at soil level; sow seed 0.5 in deep
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Soil pH
6.5-7.5
Growing Details
Soil Type
Deep, fertile, well-drained, sandy
Hardiness Zones
Zones 5 – 8
When to Fertilize
Mulch with rich compost or manure in spring
Fertilizer
Well-rotted manure or balanced fertilizer
🌱 Growing Guide
Grow sea kale in full sun in deep, fertile, well-drained soil; it thrives in sandy and even chalky ground and tolerates salt. It is slow to establish, so start seed indoors 6 to 12 weeks before the last frost (removing the corky seed coat aids the slow, uneven germination) or propagate from root cuttings, and do not harvest for the first two to three years while the crown builds strength. Cut plants down in autumn and mulch with well-rotted manure or compost in spring. To force the tender shoots, cover the dormant crown in late winter with a tall pot or bucket to exclude light, and cut the blanched shoots when several inches long.
Planting Calendar
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Start seeds indoors
Feb 18
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Transplant outdoors
Apr 29
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Projected first harvest
Jun 28 · Year 4
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
Year 1
✅ Plant alongside
Good neighbors that attract beneficial insects or deter pests
- Asparagus: Another long-lived perennial cropped from blanched or emerging spring shoots, with matching permanence
- Rhubarb: A hardy perennial that can be forced the same way and shares bed conditions
🛡️ Pest & disease prevention
Proactive ways to stop trouble before it starts. Tap a name with an arrow for its full guide
Chew the tender forced shoots; use barriers and traps, especially around blanching pots
Cabbage-family caterpillars chew leaves; handpick and use row cover or Bt
A brassica soil disease causing swollen roots; avoid infected soil, improve drainage, and rotate
Pit young leaves; use row cover on emerging growth
🌾 Harvest & storage
Begin harvesting only in the third spring, once the crown is well established. Force the shoots by covering the dormant crown to exclude light in late winter, then cut the pale, blanched shoots when they are several inches long, taking only a portion so the plant can recover. Stop cutting by late spring and let the foliage grow to rebuild the crown for next year. The blanched shoots are steamed or boiled like asparagus.
🥗 Nutrition & benefits
Sea kale shoots are low in calories and provide vitamin C and fiber. The blanched spring shoots are eaten cooked, much like asparagus, with a sweet, mild, nutty flavor.
For educational and informational purposes only. HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.