Winterbor Kale
Brassica oleracea
Plants are tall, with excellent yield and good cold hardiness. The ruffled blue-green leaves have an attractive curl. Vigorous, productive plants.
Harvest
60d
Days to harvest
Sun
Full sun to partial shade
Zones
6–9
USDA hardiness
Height
10-24 inches
Planting Timeline
Showing dates for Winterbor Kale in USDA Zone 7
All Zone 7 brassica →Zone Map
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Winterbor Kale · Zones 6–9
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | March – April | May – June | May – June | July – October |
| Zone 4 | March – April | May – June | April – June | June – October |
| Zone 5 | February – March | April – May | April – May | June – November |
| Zone 6 | February – March | April – May | April – May | June – November |
| Zone 7 | February – March | April – May | March – May | May – November |
| Zone 8 | January – February | March – April | March – April | May – December |
| Zone 9 | January – January | February – March | February – March | April – December |
| Zone 10 | January – January | February – March | January – March | March – December |
Complete Growing Guide
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: Clay, Loam (Silt), Sand. Soil pH: Acid (<6.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 0 ft. 10 in. - 2 ft. 0 in.. Spread: 1 ft. 0 in. - 2 ft. 0 in.. Spacing: 12 inches-3 feet. Growth rate: Medium. Maintenance: Medium. Propagation: Seed, Stem Cutting. Regions: Coastal, Mountains, Piedmont.
Harvesting
The fruits dry and split when ripe.
Color: Brown/Copper, Green. Type: Siliqua. Length: > 3 inches.
Garden value: Edible
Harvest time: Fall, Summer
Bloom time: Spring, Summer
Edibility: The foliage is edible raw or cooked but when cooked can emit an unpleasant odor.
Storage & Preservation
Fresh Winterbor kale stores best when harvested dry and immediately refrigerated. Remove any damaged leaves, then store unwashed in perforated plastic bags in your refrigerator's crisper drawer. Properly stored, it maintains quality for 7-10 days.
For longer preservation, blanch clean leaves in boiling water for 2 minutes, shock in ice water, drain thoroughly, and freeze in portions suitable for your cooking needs. Frozen kale works excellently in smoothies, soups, and cooked dishes for up to 12 months.
Dehydrating is another excellent option — massage clean leaves with a small amount of salt, then dehydrate at 125°F until crispy for homemade kale chips that store for months in airtight containers. The post-frost sweetness of Winterbor makes it particularly well-suited for dehydrating, as the natural sugars concentrate during the drying process.
History & Origin
Winterbor kale was developed by Johnny's Selected Seeds in the 1990s as part of their mission to extend growing seasons for northern gardeners. This hybrid variety was specifically bred by crossing traditional curly kales with exceptionally cold-hardy European winter varieties, particularly drawing genetics from Siberian kales and hardy Scottish cultivars.
The breeding program focused on creating a kale that not only survived harsh winters but actually thrived in cold conditions, developing the characteristic where frost exposure improves rather than degrades eating quality. This was achieved by selecting plants with higher natural sugar content and enhanced cold-response mechanisms.
Johnny's released Winterbor commercially in the late 1990s, and it quickly gained popularity among market gardeners and home gardeners in northern climates who wanted fresh greens through winter months. The variety represents a successful example of modern plant breeding focused on climate adaptation rather than just yield or appearance, helping gardeners extend fresh food production well into winter months when most vegetables have long finished producing.
Advantages
- +Attracts: The foliage is edible raw or cooked but when cooked can emit an unpleasant odor.
- +Wildlife value: It serves as a host plant for butterflies, moths, flies, sawflies and beetles.
- +Edible: The foliage is edible raw or cooked but when cooked can emit an unpleasant odor.
Companion Plants
Plant Together
Nasturtiums
Trap crop for aphids and flea beetles, deters cabbage worms
Marigolds
Repel cabbage moths and other brassica pests with strong scent
Onions
Deter cabbage loopers and aphids, help mask kale scent from pests
Garlic
Repels cabbage worms, aphids, and flea beetles
Dill
Attracts beneficial wasps that parasitize cabbage worms
Carrots
Deep roots don't compete, help break up soil for kale roots
Lettuce
Shallow roots complement kale, provides living mulch
Spinach
Compatible growth habits, efficient use of garden space
Keep Apart
Tomatoes
Heavy feeders that compete for nutrients, may stunt kale growth
Strawberries
Different soil pH preferences and may harbor similar pests
Pole Beans
Can shade kale and compete for nutrients during peak growth
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #168421)
Pests & Disease Resistance
Resistance
Excellent cold tolerance, resistant to bolting
Common Pests
Cabbage worms, aphids, flea beetles
Diseases
Black rot, clubroot, downy mildew