Florida Giant Watermelon Seeds. Non-GMO, annual, open-pollinated, heirloom, heat tolerant, seeded, giant watermelon. The Florida Giant watermelon, AKA: Cannon Ball Watermelon, was developed in the 1940s in Florida by Melville Dillon. Buy Seeds Online Organic Seeds Heirloom Seeds Non-GMO Seeds Vegetable Seeds Flower Seeds Herb Seeds Fruit Seeds Garden Seeds Seed Starter Kits Rare Seeds Bulk Seeds Indoor Gardening Seeds Seed Catalog Seed Packs for Sale Sustainable Seeds Greenhouse Seeds Seed Suppliers Planting Seeds Home Garden Seeds