How to Grow Ostfriesland Kale
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Ostfriesland Kale
Brassica oleracea var. acephala 'Ostfriesland'
vegetableOstfriesland is a cold-hardy German heirloom kale variety prized for its deeply curled, tender blue-green leaves and exceptional flavor that improves after frost. This compact, productive plant produces numerous harvestable leaves throughout the season and tolerates freezing temperatures exceptionally well. It's a favorite among gardeners seeking a traditional, nutrient-dense leafy green with excellent cold tolerance.
When should you plant Ostfriesland Kale in your zone?
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Example Ostfriesland Kale timeline · Pittsburgh, PA (Zone 6b)
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Plant Ostfriesland Kale
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Ostfriesland Kale
Around Jun 6≈ 50 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Ostfriesland Kale dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-8; exceptional cold hardiness makes it ideal for northern regions
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Seedling
2-3 weeksTiny plants with 2-4 true leaves, cotyledons visible
Provide bright light, maintain consistent moisture, thin to proper spacing once 2-3 true leaves appear, protect from slugs and flea beetles
Early Vegetative
3-4 weeksCompact rosette formation, 6-12 inches tall, leaves deepening in color
Thin to final spacing (18 inches), mulch around plants to retain moisture, begin regular nitrogen feeding, monitor for pests
Mid Vegetative
3-4 weeksLarger rosette, 12-20 inches tall, increasingly curled leaves, robust foliage
Begin light harvesting of outer leaves, continue consistent watering and feeding, ensure good air circulation to prevent disease
Mature/Harvest Ready
30-90+ days (continuous harvest phase)Full-sized plant 18-30 inches tall, abundant deeply curled leaves, color intensifies
Harvest outer leaves regularly to encourage continued production, flavor improves after light frost (32-40°F), continue watering and feeding
Cold Tolerance/Winter
Variable; season extension to first hard freeze (zone-dependent)Plant survives freezes, leaves become sweeter as starches convert to sugars
Continue harvesting through winter in cold regions; frost enhances flavor, reduce watering in severe cold, provide light mulch in zone 3
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Row covers, netting, hand-picking caterpillars, Bacillus thuringiensis (Bt), companion planting with dill or fennel
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Row covers over seedlings, kaolin clay spray, neem oil, diatomaceous earth, reflective mulches
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Strong water spray to dislodge, insecticidal soap, neem oil, ladybug introduction, reflective mulches
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Hand-picking, Bt spray, neem oil, row covers, encourage beneficial wasps
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and
Copper tape barriers, beer traps, handpicking at night, diatomaceous earth, encourage predatory beetles
Uses
Nutrient-Dense Leafy Green
CulinaryOstfriesland kale is rich in vitamins A, C, and K, plus minerals like calcium and iron. Use raw in salads when young and tender, or sauté, braise, or add to soups and stews. [source]
Cold-Weather Delicacy
CulinaryAfter frost exposure, sugars accumulate in the leaves, creating a sweeter, more tender flavor profile. Ideal for chips, salads, and traditional German dishes. [source]
Antioxidant & Anti-inflammatory
MedicinalContains glucosinolates and sulforaphane compounds with potential anti-cancer and anti-inflammatory properties. Traditionally used in European folk medicine. [source]
Seasonal Food Preservation
HouseholdExcellent for freezing, dehydrating into chips, or fermenting into sauerkraut-like preparations. Stores well in cool conditions. [source]
Pollinator & Beneficial Insect Support
WildlifeIf allowed to bolt and flower, produces attractive yellow blooms that attract bees and beneficial insects while providing late-season forage. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Begin harvesting outer leaves when plant is 12+ inches tall, leaving inner leaves to continue growing. Pinch or cut leaves at the base for continuous production. Most productive when leaves are 6-12 inches long and deeply curled. Flavor sweetens significantly after first light frost (around 32-40°F). Can be harvested throughout winter in cold climates. Morning harvest after frost provides best quality and flavor.
Fun Facts
- 🌱 Ostfriesland is a traditional German heirloom variety from the East Frisia region; it has been cultivated for centuries and remains a staple in European winter gardens.
- 🌱 Unlike many kale varieties, Ostfriesland's flavor actually improves after exposure to frost, as the plant converts starches to sugars as a natural antifreeze mechanism.
- 🌱 This variety is particularly cold-hardy and can survive temperatures well below freezing, making it one of the best kales for season extension in northern climates where it can be harvested into late fall or even winter.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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