Siberian Kale

Siberian Kale
Tender, blue-green leaves with a mildly sweet flavor. The plants are tall, vigorous and high yielding. More tender than the extra curly green varieties but not quite as cold hardy. Pairs well with Red Russian.
Plant from early spring to approximately 3 months before expected fall frost. For bunching, sow 3–4 seeds every 12–18″, ½” deep, in rows 18–36″ apart. Thin to 1 plant per group. For baby leaf production, sow 60 seeds/ft. in a 2–4″ wide band ¼–½” deep.
Early Spring: Use varieties suited to warm season production. Sow 2 seeds per cell in 50- to 72-cell plug flats, 3–4 seeds/in. in 20 row flats, or in outdoor beds ¼” deep. Seedlings should be ready to transplant in 4–6 weeks. If possible keep soil temperature over 75°F (24°C) until germination, then reduce air temperature to about 60°F (16°C). Transplant outdoors 12–18″ apart in rows 18-36″ apart. Kale prefers cooler growing temperatures, between 55–75°F (13–24°C), optimum being 60–70°F (16–21°C), but will produce good crops under warmer, summer conditions.
Start seedlings as above in May and transplant to the garden in June–July. To ensure mature heads, seed the crop early in areas where heavy freezes occur early in fall.
Successful kale crops can be grown where winters are mild (temperatures rarely below 32°F (0°C)). Transplants can be set out from September to February in these regions.
Days to maturity:
From direct seeding; subtract about 14 days if transplanting.
Beginning about 2 months after planting, harvest by clipping individual leaves. Kale is very hardy, and the eating quality will improve into the late fall with light frost. Late summer sown or planted collards can be wintered in cold frames or hoophouses, or in the open in mild regions, to extend the season. Protecting with row covers can extend the harvest period.