Red Panda Sorrel Seeds. Annual. Herb. Heirloom. Rumex sanguineus. AKA: Spinach Dock and Narrow-Leaved Dock. 55 days. Red Panda sorrel herb produces a far more exotic red stem coloring than that of Red Veined sorrel, while boasting all the same culinary notes. Similar to Red Veined sorrel, Red Panda sorrel can be grown as a quick 14-21 microgreen crop for easy indoor herb gardens and harvesting. About 15,000 seeds per ounce.