True Siberian Kale Hardy biennial (60-70-day) Large, frilly blue-green leaves identify this fast growing, exuberant kale. Slow to bolt in summer, it withstands hard frosts, which sweeten its flavor and improve its texture. Planting depth: 1/4 - 1/2-inch Soil Temperature for Germination: 60-65-Degree F, day to Germination: 5-10 Avg. Spacing: 4-8 seeds/foot in rows 12-18-inch apart Avg. Seeding rate: 1-2-pound./acre-day to maturity: 50-60 Partial shade/full sun Moderate water, 100 Seed Count.