45 Days to maturity, 10-15 days for microgreens, and 20-30 days for baby leaf. Brassica rapa var. narinosa. Savoy Tatsoi Pak Choi Seeds. Cool-Warm Season Annual Heirloom. This dark green, heavily savoyed leaves grow atop thick bunches of pale, green petioles giving it a spinach-like appearance. In summer, the plant reaches nearly a foot in height. In winter, it grows in a rosette close to the ground. As with Tatsoi, individual leaves can be picked continuously for several weeks. Heat and Cold tolerant. Excellent for microgreens and baby leaf production. ~ 10,000 seeds per oz.