Also called napa cabbage, 'One Kilo Slow Bolt' has a delicate flavor, a soft texture in between that of lettuce and regular cabbage, and tight heads have a creamy yellow interior. Grows with ease in fall, and can be sown in spring if care is taken to protect young plants from temperatures of 50°F or below, which may cause plants to bolt. Grows best at 60°-65°F.
• Botanical Name: Brassica rapa var. pekinensis (hybrid)
• Days to Maturity: 50–55 days
• Family: Brassicaceae
• Native: Unknown
• Hardiness: Frost-tolerant biennial, grown as an annual
• Plant Dimensions: About 9" tall, 20" wide including lateral leaves; the head is about 11" tall and 7" wide
• Variety Information: Outer leaves are green and white with a yellowish-green interior. Leaves have a lightly crinkled texture at maturity and have a sweet flavor. Mature, trimmed heads weigh 2–2 ½ pounds. 'One Kilo Slow Bolt' is a wong bok/napa type cabbage.
• Attributes: Good for Containers
• When to Sow Outside: RECOMMENDED. 2 to 4 weeks before your average last frost date for a summer crop or 8 to 10 weeks before your average first fall frost date for a fall crop. Ideal soil temperature for germination is 75°-85°F. Persistent temperatures of 50°F or below while plants are young can cause bolting (premature flowering), cover as necessary.
• When to Start Inside: 4 to 6 weeks before your average last frost date transplanting after your average last frost date, and 4 to 6 weeks before transplanting outdoors in summer for a fall crop. Sow in biodegradable pots to avoid root disturbance. Mild Climates: Sow in fall for a cool-season harvest.
• Days to Emerge: 7–12 days
• Seed Depth: ¼"
• Seed Spacing: A group of 3 seeds every 12"–18"
• Row Spacing: 24"–30"
• Thinning: When 3" tall, thin (and eat!) to 1 every 12"–18"
• Harvesting: Harvest heads when they are well developed, firm, and solid when squeezed. Cut off heads at base with a sharp knife. Cabbages left in the ground beyond maturity are more subject to disease and splitting. Harvest in the morning if possible. If harvested in the heat, dunk in ice water to reduce "field heat" and increase storage time. Allow to drain before storing.