Cabbage Seeds - Pak Choi - Da Hong Summer - Hybrid. Non-GMO. Brassica rapa Chinensis Group. 10-15 days microgreens; 20-30 days baby leaf; 45 days full maturity. Cool season annual. Da Hong Summer is slightly denser than other purple pak choi former a more developed head and firmer petioles. Leaf color is Dark violet-red with green petiole color It s heat tolerance is higher than many other pak choi and it can also weather greater temperature fluctuations between day and night without bolting. Prepare fertile well-drained soil. Sow seeds in spring after last frost to early summer or late summer/early fall. Keep soil moist. Fertilize as needed. Optimum growing temperatures are in the 60s°F. Exposure to frost or prolonged temperatures below 50°F may result in bolting. Mulch fall crops to avoid premature bolting. Most vegetables leave having purple color is called anthocyan which is generally developed by lower temperature. Growing temperatures 50-60°F should be adequate to develop anthocyan after the seeds have germinated. We cannot tell exactly how long exposure should be under low temperatures. The grower should trial different methods and observe how the plant reacts. Can be eaten fresh. Mature plants are steamed stir-fried and braised. Approx 9500 seeds / oz.