Vates Collards Brassica oleracea. Hardy Biennial. Also known as Blue Stem, this robust collard has broad, thick dark blue-green leaves. Very tolerant of temperature extremes, bolt resistant and can over-winter in the mid and deep South.Planting Depth: 1/4″ Soil Temp for Germination: 50-75 deg FDays to Germination: 3-10Days to Maturity: 65-80Part to Full SunModerate Water