These sweet, crisp napa cabbages are ideal for salads and a mainstay of the stir-fry, great for cabbage rolls too. Direct sow in summer with the last planting about 10 weeks before frost. A great hardy plant that withstands some cold and can stay in the garden until late October early November or until the weather gets severe.  Small plants will bolt if exposed to temperatures under 10 C for 7-14 days.  Early spring crops and late fall crops should be covered with clothe covers to ensure heavy heads.