40-45 Days to maturity. Brassica rapa Chinensis group. Summer Zest Pak Choi Seeds. Cool-Warm Season Annual Hybrid. Summer Zest is considered a medium to large size cabbage or medium maturing pak choi. It is one of the best heat tolerant varieties on the market! The plant grows erect and compact. It is tolerant to heat, rain, with some disease resistance. Good for Late spring and fall planting. Leaves are dark green color, oval-spoon shape.~ 3,000 seeds per oz.