Botanical Name: Brassica rapa var. pekinensis (hybrid)
Days to Maturity: 50–55 days
Native: Widespread, probably Eurasia
Hardiness: Frost-tolerant biennial, grown as an annual
Plant Dimensions: 8" tall, 10" 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: 1 to 2 weeks after your average last frost date, when soil temperature is at least 55°F, ideally 75°–85°F, or 8 to 10 weeks before your average first fall frost date. In Mild Climates, sow in the fall for cool–season harvest.
When to Start Inside: Recommended for spring planting. 4 to 6 weeks before your average last frost date, or 8 to 10 weeks before average first fall frost for fall crop. Start in biodegradable pots that go directly in the ground for minimal transplant shock. See more spring planting tips inside the packet.
Days to Emerge: 10–15 days
Seed Depth: ¼"
Seed Spacing: A group of 3 seeds every 20"
Row Spacing: 24"–30"
Thinning: When 3" tall, thin (and eat!) to 1 every 20"
Harvesting: Fall crops should be harvested before a hard frost (though it may be hardy down to 28?F or lower when protected with row covers). Spring crops should be harvested before seed stalks form. Harvest heads after they firm up and are solid. Cut just above the soil surface (young, tender, edible leaves may sprout from stump!) As you are thinning seedlings, use the tender young leaves in salads, or you can harvest whole plants when they are young, 3"-4" tall.