Collard Growing Information Brassica oleracea Direct Seed: When soil temperature is a minimum of 55° F. Transplant: Sow in trays ½” deep 4-6 weeks before desired transplant date. Soil temperature for germination is 55-75° F. Spacing: Thin direct-seeded planting or transplant at 12-15” in rows 18-36” apart. Growth needs: Prefers cool weather, but will perform in summer growing conditions in most areas. Grows best in well-drained soil with high fertility and consistent water. Harvest: When leaves are of desired size, about 8 weeks after sowing date. Storage: Store in bunches or loose in plastic in a cooler for 2 weeks at 36F at 95% relative humidity.