Sprouting Broccoli Growing Information Brassica oleracea var. italica Transplant: Start in trays at ¼” depth in mid-summer for overwintering varieties or 3-4 weeks before desired transplant date for all-season varieties. Soil temperature for germination is 55-75° F. Spacing: 12-24" apart in rows that are 24-30" apart. Growth needs: Likes well-drained soil that is high in organic matter. Irrigate regularly and add nutrients for best yield. Overwintered sprouting broccoli needs a vernalization period of temperatures consistently below 50° F. Harvest: Cut central head while beads are still tight, and typically 3-4" diameter, to stimulate growth of side shoots. Cut stems at 4-8" for bunching or bulk sales. Harvest regularly for continued production of up to 6 weeks.