Joy Black Seedless Grapes. are deep blue, almost black table grape from the University of Arkansas is one of the most flavorful of their introductions. Unusual for a dark, non-slipskin grape, Joy’s fruit are quite soft, very thin-skinned, with no notable astringency from the skin. Fruit holds well on the vine when ripe. Berry weight averages 3 g and clusters weight is usually near 300 g. Average harvest date is August 11th in Arkansas. Vine yield is usually moderate to high, and vines have moderate vigor along with consistently good vine health. zones 5-8 offered by Pense Nursery, Inc.