40-50 days to maturity.Brassica rapa var chinensis. Joi Choi Hybrid Pak Choi Chinese Cabbage Seeds. Non-GMO, warm or cool-season annual, hybrid. Growers love this hybrid pak choi for its uniformity. It is large, fast-growing, vigorous, and has bright green leaves and white petioles. At maturity, the plant is about 18 inches tall yet can be harvested when plants are still young and small. This variety is recommended for areas where bolting is a problem when growing pak choi; this is a very adaptable variety that tolerates a wide range of temperatures.~ 8,500 seeds per oz.