Botanical Classification
Scarlet kale, scientifically classified as Brassica oleracea var. acephala, belongs to the Brassicaceae family, which includes cruciferous vegetables such as cabbage, broccoli, and other kales. The acephala variety denotes non-heading brassicas, characterized by loose, leafy rosettes rather than compact heads.
Scarlet kale is an open-pollinated cultivar of curly kale, bred for its vibrant purple foliage and nutritional richness, sharing its genetic lineage with wild cabbage (Brassica oleracea) from the Mediterranean. Its classification aligns it with other kale varieties selected for both culinary and ornamental qualities, emphasizing its anthocyanin-rich leaves.
Origin and History
Kale has ancient origins in the eastern Mediterranean and Asia Minor, cultivated since around 2000 BCE by Greeks and Romans. Curly kale varieties, including Scarlet kale’s ancestors, became staples in northern Europe during the Middle Ages for their cold tolerance. Scarlet kale, a modern open-pollinated cultivar, was developed in Europe, likely in the late 20th century, to enhance purple pigmentation and antioxidant content.
Its striking color made it popular in both edible and ornamental gardening. The cultivar gained traction during the 21st-century superfood movement, spreading globally, including to Ecuador’s highlands, where cool climates and fertile volcanic soil support its cultivation for local and export markets, driven by demand for nutrient-dense greens.
Identifying Characteristics
Scarlet kale is distinguished by its deeply curled, frilly leaves in vivid shades of deep purple to magenta, which intensify after frost exposure. The leaves form a loose rosette, growing 2-3 feet tall and wide, with a texture similar to curly kale but softer. Stems are purple, edible when young but toughening with age, and the foliage has a slightly waxy coating that enhances its visual appeal.
Its vibrant color, due to high anthocyanin content, makes it a standout in gardens and on plates, serving as both a culinary ingredient and an ornamental plant, often used in borders or mixed beds.
Taste
Scarlet kale has a robust, slightly bitter, and peppery flavor with earthy, nutty undertones, akin to curly kale but with a milder, sweeter profile due to its tender leaves. Its texture is crisp when raw, softening to a cabbage-like consistency when cooked. Massaging raw leaves with oil or acid reduces bitterness, making them ideal for salads.
Light frosts enhance sweetness by converting starches to sugars, improving flavor for fall and winter harvests. Its bold yet approachable taste pairs well with bold seasonings, citrus, or creamy ingredients, enhancing its culinary versatility.
Seasons/Availability
Scarlet kale is a cool-season crop, thriving in temperatures between 7-24°C (45-75°F), with frost tolerance down to -12°C (10°F). It’s planted in early spring or late summer, maturing in 50-65 days. In Ecuador’s highland regions, like Cayambe, year-round cultivation is possible due to consistent cool temperatures and fertile soil, ensuring global availability.
In temperate climates, it’s harvested from late summer through winter, surviving light snow. Scarlet kale is available fresh in specialty markets during cooler months, with limited year-round supply in supermarkets, often as mature or baby leaves.
Culinary Uses
Scarlet kale’s vibrant color and hearty texture make it a versatile ingredient in modern and traditional cuisines. Raw, its leaves are massaged for salads, pairing well with citrus dressings, nuts, or cheeses to balance its slight bitterness, with its purple hue adding visual appeal. It’s used in smoothies for a nutrient boost, retaining its vivid color.
Cooked, Scarlet kale shines in soups, stews, or stir-fries, holding its structure when sautéed with garlic or olive oil. Baking it into crispy kale chips is a popular option, showcasing its color and flavor. Young stems are edible, while mature ones can flavor broths, offering zero-waste versatility.
Nutritional Value
Scarlet kale is a nutritional powerhouse, low in calories (about 35 per cup raw) and rich in vitamins, minerals, and antioxidants. It’s an excellent source of vitamins K, A, and C, providing over 100% of daily needs per serving, supporting blood clotting, vision, and immune health. It contains 2-3 grams of fiber per cup, aiding digestion, and is high in calcium, iron, and magnesium for bone and blood health.
Its deep purple color reflects high levels of anthocyanins, antioxidants with anti-inflammatory and heart-protective properties, alongside quercetin, kaempferol, and glucosinolates, which may offer cancer-preventive benefits. Scarlet kale also provides folate and omega-3 fatty acids, making it a valuable addition to plant-based diets.
Cultivation of Scarlet Kale
- Climate and Season: Scarlet kale grows best in cool weather, with optimal temperatures between 7-24°C (45-75°F), and tolerates frosts down to -12°C (10°F). Plant in early spring or late summer for spring and fall harvests. In Ecuador’s highlands, year-round cultivation is possible due to consistent cool climates, ideal for vibrant leaf color.
- Site Selection: Choose a site with full sun (6-8 hours daily) to enhance purple pigmentation and growth, though partial shade is tolerated in warmer climates to prevent bolting. Ensure good air circulation to minimize fungal diseases, particularly in humid regions like parts of Ecuador.
- Soil Requirements: Prefers fertile, well-drained, loamy soil with a pH of 6.0-7.5. Enrich with organic matter like compost or aged manure. In Ecuador, test volcanic soils for acidity and amend with lime if pH is below 6.0 to optimize nutrient uptake for anthocyanin-rich leaves.
- Soil Preparation: Loosen soil to 12 inches deep, mixing in 2-3 inches of compost or organic matter. Remove rocks and debris to support root development. A soil test confirms proper pH and nutrient levels, essential for producing tender, colorful foliage.
- Planting: Sow seeds ¼-½ inch deep, spacing 12-18 inches apart in rows 18-24 inches apart to accommodate its 2-3 foot spread. Transplant seedlings started indoors 6-8 weeks earlier for faster growth. In Ecuador, indoor seeding protects against variable weather, ensuring uniform plants.
- Watering: Maintain consistent soil moisture, providing 1-1.5 inches of water weekly, avoiding waterlogging. Use drip irrigation to keep leaves dry, reducing disease risk in humid climates. Mulch to retain moisture and stabilize soil temperature for healthy growth.
- Fertilization: Apply a balanced fertilizer (e.g., 10-10-10) at planting, followed by a nitrogen-rich fertilizer (e.g., fish emulsion) every 4-6 weeks to promote leafy growth. Avoid over-fertilizing to prevent soft leaves that attract pests and maintain vibrant color.
- Mulching: Add a 2-3 inch layer of organic mulch, such as straw or bark, to conserve moisture, suppress weeds, and keep roots cool. This is particularly effective in Ecuador’s fluctuating climates to stabilize soil conditions and enhance plant vigor.
- Pest Management: Monitor for pests like aphids, cabbage worms, and flea beetles, common in brassica crops. Use row covers, neem oil, or introduce beneficial insects like ladybugs. Hand-pick caterpillars for organic control, protecting the striking foliage.
- Disease Control: Prevent fungal diseases like powdery mildew and black rot by ensuring good air circulation and avoiding overhead watering. Rotate crops every 2-3 years to reduce soil-borne pathogens, a critical practice in Ecuador’s intensive farming regions.
- Harvesting: Harvest outer leaves when 6-8 inches long, about 50-65 days after planting, cutting close to the stem to encourage regrowth. Leave the central bud intact for continuous leaf production. Harvest after light frosts for sweeter, tender leaves, ideal for culinary use.
- Succession Planting: Sow seeds every 2-3 weeks in spring or fall for a steady supply of fresh leaves. In Ecuador’s highlands, staggered planting ensures year-round harvests due to the mild climate, meeting demand for both culinary and ornamental markets.
- Storage and Preservation: Store fresh Scarlet kale at 0-4°C (32-40°F) in a perforated plastic bag in the refrigerator for up to 2-3 weeks. For long-term storage, blanch leaves for 2-3 minutes, cool in ice water, dry thoroughly, and freeze to preserve nutrients and vibrant color. Wash and dry before storing to maintain freshness.