Giant Noble Spinach Vegetable Seeds. An heirloom spinach with giant leaves that can spread up to 25 inches. Slow to bolt, excellent for canning. Smooth, large, dark green leaves are an old time favorite. Spinacia oleracea. Also known as Giant Nobel. Annual. 43 days to maturity. 12-18" height. 2-3" spacing. Produces thick, smooth, dark green leaves.