40 to 50 Days to maturity. Brassica rapa narinosa. Rosette Tatsoi Chinese Cabbage (Pak Choi) Seeds. Non-GMO, Open Pollinated, Heirloom, Annual. This specialty pak choi is quite cold-tolerant, even being able to be harvested in snow. Leaves are spoon-shaped and dark green in color. The plant stems, or petioles, are shorter than most pak choi varieties. In warmer temperatures, the plant grows erect while in cold temperatures the plant forms flat rosettes growing close to the ground. This variety of pak choi prefers mild and cool temperatures. Approx 10,000 seeds / oz.