Klondike Blue Ribbon Watermelon
Citrullus lanatus
Approximately ~ 20 seeds per pack
Packed for 2026
Quick Reference: Annual | Full Sun | Approx. Zones 3–11 | Sow ½–1 inch deep | Space 36–60 inches | Rows 6–8 feet | Approx. 85–90 days | Harvest when nearest tendril browns and ground spot becomes creamy yellow.
Origins and History of Domestication
Klondike Blue Ribbon Watermelon belongs to Citrullus lanatus, a species whose deeper ancestry traces to Africa. Watermelons underwent a long process of domestication and selection before spreading through the Mediterranean region, Asia, and eventually the Americas. Klondike Blue Ribbon is part of the American heirloom tradition that emerged from further selection for fruit quality, shipping durability, productivity, and adaptation to regional growing conditions.
The history of the Klondike family of watermelons is especially associated with California. Historical variety records distinguish Klondike Blue Ribbon from the older Klondike strains. Period seed catalogs have advertised Striped Klondike Blue Ribbon as a wilt-resistant improvement of the older Striped Klondike.
Spread and Diversification
The Klondike watermelon group became important in California as market and shipping melons during the first half of the twentieth century. Selection within the group produced several named strains, including brown-seeded, black-seeded, striped, Blue Ribbon, and wilt-resistant forms. Historical descriptions indicate that Blue Ribbon preserved the desirable qualities of Striped Klondike while adding resistance to Fusarium wilt. Cornell's variety database notes that Klondike Blue Ribbon Striped was once a popular shipping melon, particularly on the West Coast during the World War II era. Today, Klondike Blue Ribbon is maintained as an open-pollinated heirloom watermelon, allowing gardeners and seed stewards to save seed while maintaining the variety through appropriate isolation and selection.
Appearance and Characteristics
Klondike Blue Ribbon produces vigorous spreading vines and large, generally oblong to blocky watermelons. Fruits commonly reach 20–30 pounds, although size varies with climate, fertility, and growing conditions. The rind is attractive light to medium green with contrasting darker green stripes. Although relatively thin, the rind is tough enough to provide good protection against cracking and handling damage.
Inside, the fruit has bright scarlet to deep red flesh that is crisp, juicy, and notably sweet. The combination of large fruit, attractive striping, sweet flesh, and a durable rind helped make the Klondike types useful both as home-garden watermelons and historically as market melons. The variety is also valued for resistance to Fusarium wilt, and some modern sources report resistance or tolerance to anthracnose and sunburn as well.
Culinary Uses
Klondike Blue Ribbon is an excellent fresh-eating and picnic watermelon. Its crisp, sweet red flesh is best served chilled and eaten in wedges or cubes. It also works well in fruit salads, watermelon salsa, chilled summer beverages, smoothies, sorbets, and other fresh preparations. The fruit can be paired with mint, basil, cucumber, citrus, or mild cheeses for summer salads. Like other traditional seeded watermelons, mature seeds may also be saved for future planting when the crop has been adequately isolated from other watermelon varieties.
Growing Tips and Vegetation Zones
Klondike Blue Ribbon is a warm-season annual requiring full sun, warm soil, and a relatively long frost-free growing period. Although watermelon is not technically assigned perennial USDA hardiness zones because it is grown as an annual, this variety can be cultivated through a broad range of approximately Zones 3–11 when planted during sufficiently warm weather. Gardeners in northern zones should start seeds indoors about 3–4 weeks before the last frost, while growers in warmer regions can direct sow after frost danger has passed.
For direct sowing, wait until the soil has warmed to at least 70°F, with approximately 70–85°F providing favorable germination conditions. Plant in fertile, loose, well-drained soil enriched with compost or aged manure. Water consistently during vine development and fruit set, but avoid prolonged waterlogging. Because the vines require considerable room, allow approximately 3–5 feet between plants or hills and 6–8 feet between rows. Mulching helps conserve moisture, suppress weeds, and keep developing fruit away from wet soil.
Sowing Depth
Sow seeds approximately ½–1 inch deep outdoors. When starting indoors, seeds can be planted about ¼–½ inch deep in individual biodegradable pots to minimize root disturbance at transplanting. Watermelon roots dislike excessive handling, so transplant seedlings carefully after temperatures have become reliably warm.
Days to Maturity
Allow approximately 85–90 days to maturity, depending on climate and growing conditions. Cornell lists Klondike Blue Ribbon Striped at 80–90 days, while historical records and several current sources place it around 85–90 days. Warm temperatures and consistent growing conditions generally encourage the best fruit development.
Harvesting Guidance
Determining watermelon ripeness is best done by looking for several signs together rather than relying solely on fruit size. Watch the curly tendril nearest the fruit stem; as the melon reaches maturity, this tendril normally dries and turns brown. The area where the watermelon rests on the ground should change from pale white or greenish-white to a creamy or buttery yellow, while the rind tends to become somewhat duller rather than glossy.
Harvest by cutting the stem with pruning shears or a sharp knife, leaving a short portion of stem attached rather than pulling the fruit from the vine. A mature Klondike Blue Ribbon should feel heavy for its size and reveal crisp, richly colored red flesh when cut. Because these melons can commonly reach 20–30 pounds, support or protect developing fruits from prolonged contact with damp soil.
