Grandeur Watermelon

Start seeds indoors 4-5 weeks before your last spring frost. Use warm soil (70-80°F) and sow seeds 1 inch deep in individual pots to minimize transplant shock. Keep soil consistently moist but not waterlogged. Seedlings should be ready to harden off within 5-6 weeks, though only transplant outdoors once nighttime temperatures remain above 65°F and soil has warmed to 70°F or higher.

Harden off seedlings over 7-10 days by gradually exposing them to outdoor sun and wind. Transplant into warm soil (70°F minimum, ideally 75-80°F) after your last frost date. Space plants 36 inches apart in rows 36 inches apart. Dig a generous planting hole, incorporate aged compost, and water deeply after transplanting. Mulch around the base to conserve moisture and keep soil warm.

Direct sowing is possible in warmer zones (7-13) where soil consistently reaches 70°F by late spring. Sow seeds 1 inch deep, 3-4 seeds per hill, thinning to the strongest plant once vines emerge. Wait until all frost danger has passed and soil is genuinely warm, as seeds will rot in cold soil.

Harvest when melons reach full size (typically 25-30+ pounds) and the underside develops a creamy yellow spot where it rested on soil. Thump the melon with your palm; a ripe fruit produces a hollow, resonant sound rather than a high-pitched ping. The tendril nearest the fruit's stem will begin to dry and brown as ripeness approaches. Cut melons from the vine with a sharp knife rather than twisting them off; this reduces vine damage and bruising.

Grandeur's indeterminate, sprawling growth habit means minimal pruning is needed; allow vines to run across the soil or along trellises. If space is severely limited, you can selectively remove older runners to direct energy toward developing fruits, but this hybrid's vigor means it will produce abundantly with minimal intervention.