CERTIFIED ORGANIC! When small, the lovely burgundy coloured leaves with light green veins are so mild and delicious they can be eaten in salads. In summer, big leaves pack a proper mustard punch but they are much milder when cooked or when grown in cooler weather. Very winter-hardy, Giant Red Organic mustard seeds can be planted into October or in early spring to harvest as small leaves every few days. For big plants, thin to 20-30cm (8-12") in the row.