45-50 days. Zucchini Grey Summer Squash Seeds. Cucurbita pepo. Non-GMO. Open Pollinated. An Old World heirloom native to Italy, the Zucchini Grey summer squash has been a Mediterranean favorite since the early 1800s. Since then, Zucchini Grey squash seeds have lent itself to numerous seasonal hybrids and cultivars of Italian summer squash. Unlike plain green varieties of squash seeds, Zucchini Grey boasts a uniquely striped skin very similar to a Greyzinni hybrid. Approx 258 seeds/oz.