Black Diamond Watermelon Seeds

Black Diamond is one of the most famous heirloom watermelons ever introduced, celebrated for its enormous size, nearly black rind, and exceptionally sweet crimson-red flesh. For generations, this classic variety has been a favorite among home gardeners, commercial growers, and county fair exhibitors who appreciate its dependable production and impressive appearance. Its combination of old-fashioned flavor, vigorous growth, and giant fruits has earned Black Diamond a permanent place among America's finest heirloom watermelons.

The large, round to slightly oval fruits commonly weigh between 30 and 50 pounds, with exceptional specimens often exceeding 75 pounds under ideal growing conditions. The smooth, dark green rind is so deep in color that it appears almost black, creating a striking contrast with the brilliant crimson-red flesh inside. The flesh is firm, crisp, remarkably juicy, and exceptionally sweet with the rich, old-fashioned watermelon flavor that has delighted families for decades. Its thick rind provides excellent protection during harvest and transport while helping maintain freshness after picking.

Black Diamond thrives during long, hot summers where full sun and fertile, well-drained soil encourage vigorous vine growth and heavy fruit production. Plants develop long, sprawling vines that require generous garden space but reward growers with dependable harvests of truly impressive melons. Regular watering during fruit development promotes maximum size and quality, while reducing irrigation as the fruits mature helps concentrate sugars and produce their outstanding sweetness.

Whether grown for family picnics, roadside markets, county fairs, or simply to enjoy a true heirloom classic, Black Diamond consistently delivers spectacular results. Its massive fruits, beautiful dark rind, crisp crimson flesh, and dependable productivity continue to make it one of the most recognized and respected watermelon varieties ever developed. Few heirloom watermelons have earned such lasting popularity among gardeners throughout North America.

Specifications

• Plant Type: Annual warm-season vine
• Fruit Shape: Round to slightly oval
• Rind: Smooth, very dark green (nearly black)
• Flesh Color: Deep crimson red
• Fruit Weight: 30–50 pounds (larger under ideal conditions)
• Days to Harvest: Approximately 90–95 days
• Vine Length: 10–15 feet
• Sun Requirements: Full sun
• Soil Requirements: Rich, fertile, well-drained soil
• Uses: Fresh eating, farmers markets, roadside stands, home gardens, exhibitions, family gatherings

Disease Resistance

Black Diamond is a vigorous heirloom variety that performs exceptionally well when grown using good cultural practices. Crop rotation, proper plant spacing, fertile well-drained soil, and consistent watering help maintain healthy vines while minimizing common watermelon diseases such as anthracnose, fusarium wilt, gummy stem blight, and powdery mildew.

Seedman Notes

Few watermelons are as instantly recognizable as Black Diamond. Its nearly black rind, giant fruits, and rich crimson flesh have made it a favorite for generations of gardeners who appreciate old-fashioned watermelon flavor. If you have plenty of garden space and enjoy growing truly impressive melons, Black Diamond is one of the finest heirloom varieties you can plant. It remains a timeless classic that continues to produce some of the sweetest and most memorable watermelons of summer.