Rainbow Chard Seed: 56 days. What other vegetable offers so much: beauty to the eye, rich flavor, and significant nutrient content. Cook Rainbow Chard until just tender (add quicker cooking leaves and young stems last) to preserve the nutritional qualitiesand the beautiful color of the stalks. Vigorous, productive easy-to-grow upright plants. Somewhat milder taste and less hardiness than regular Swiss Chard. At 30 days young leaves are a nice addition to salads. 1875 seeds/oz. Pkt (~130 seeds) plants 22'.