78 days. Over the years, we have tested hundreds of cabbage varieties at our London Spring research farm, and Ruby Ball Improved remains a great all-season red cabbage. Firm, 6–8 inch round heads have a mild, sweet flavor and weigh a manageable 3–4 pounds. We have seen this variety stand unfazed in the garden for 6 weeks without splitting, which allows the gardener extended fresh harvests. Ruby Ball Improved stores moderately well after harvest.