70 Days to maturity. Brassica rapa var pekinensis 'Green Rocket'. Green Rocket Hybrid Cabbage Seeds. Annual Hybrid. Green Rocket is a popular Michihili-type cultivar known for its early maturity (for a Michihili-type) and sweet taste. You can expect to see 4-4.5 pound cylindrical heads form with vigorous growth and disease resistance. Its leaves show off frilly edges at the top of the cabbage head. If you are new to Chinese Cabbage this is a good variety to try. About 5,300 seeds per oz.