The winds here in spring really dry things out quickly. Timing of sowing is another important consideration for planting grass seed in zone 6. Winter Sowing Seeds A Quick Start Guide Winter Vegetables Gardening Garden Seeds Planting Seeds Outdoors Generally in the case of cool-season grasses the best time to plant grass seed is during the late summer or early fall. Planting grass seed in cold weather . Cool-season grasses like Jonathan Green Black Beauty can be planted in cool temperatures. Once the grass is up and can be cut to the usual 2 or 3 inches then it is ready to be mowed. Zone 6 is considered a cool season grass zone even though it can have very hot summers. This roughly corresponds to daytime air temperatures in the 60F to 75F range. Cool-season grass seed germinates best when soil temperatures are between 50F and 65F. Stressful summer heat could slow or completely stop the growth of cool-season grasses. So yes you can plant cool-season grass in spring ...