Growing Watermelons: A Complete Guide for Summer Gardens

Watermelon is the quintessential summer fruit, and while it belongs to a different genus than other melons, its growing requirements are remarkably similar—just on a grander scale. Watermelons typically demand even more space than their melon cousins, which can be intimidating for gardeners with limited room. The good news is that the expanding variety of cultivars means you can find a watermelon suited to almost any garden size. Browse seed catalogs or visit nurseries and you'll discover seedless watermelons, "personal" single-serving melons, orange-fleshed varieties, compact bush types, and heirloom selections—enough diversity to dedicate an entire garden to watermelons alone.

If you plan to include watermelons in your summer garden, be prepared to allocate a significant portion of your space and provide plenty of long, hot, sunny days. You'll also need patience: harvest typically arrives two to three months after planting.

When to Plant

Outdoor planting: In spring, once all danger of frost has passed and soil temperature reaches 75°F (24°C)—usually at least two weeks after your last frost date.

Indoor starts: Begin seeds indoors about three to four weeks before that outdoor planting date.

Key Growing Requirements

• Days to maturity: 68–95 days
• Light: Full sun
• Water: Regular, consistent moisture

Favorite Varieties

Bush Sugar Baby, Crimson Sweet, Glory, Ice Box, Moon and Stars, New Queen, Orange Crisp, Orange Sweet, Petite Treat, PureHeart Seedless, Rattlesnake, Ruby, Seedless, Sugar Baby, Sweet Beauty, White to Yellow Cut, Yellow Doll.

Note: Seedless watermelons require a seeded variety planted nearby for pollination and fruit set.

Planting Methods

Choose a warm, full-sun location with very rich, well-drained soil. Amend the planting area generously with compost before planting. Watermelon vines need ample room to sprawl—easily covering 100 square feet or more.

Hill Planting (Preferred)

• Create raised hills 3–4 inches high and 4–6 feet in diameter.
• Space hills 8 feet apart.
• Sow seeds 1 inch deep, placing 4–5 seeds per hill.
• Thin to the two strongest plants per hill.

Row Planting

• Form mounded rows 4 feet wide, spaced 8 feet apart, with watering furrows or basins alongside.
• Sow seeds 1 inch deep, two seeds every foot along the row.
• Thin to one plant every 4 feet.

Transplants should be set out at the same spacing. Install any trellises or supports at planting time to avoid disturbing roots later.

Small-Space Solutions

If space is limited, opt for mini or compact varieties. These need as little as 2–4 feet of space and can even thrive in large containers. Follow the same planting depth recommendations.

Care and Maintenance

• Watering: Water deeply and regularly to keep soil moist but not waterlogged. Use watering basins or furrows to keep water off foliage and fruit, reducing disease risk.
• Fertilizing: Apply a complete fertilizer every six weeks.
• Fruit support: Place a brick, piece of wood, or foam under each developing fruit to keep it off the soil. For trellised vines, create slings from netting or stockings to support fruits once they reach about 2 inches in diameter.

Pests and Diseases

Watermelons share many pests and diseases with other melons. Common pests include aphids, cucumber beetles, and squash vine borers. Protect seedlings with row covers, but remove them when plants flower to allow pollination. Fungal issues like mildew, rot, and wilt can also occur.

Harvesting

Determining ripeness is both art and science—watermelons do not continue to ripen once picked. The classic method is to thump the melon and listen for a dull, hollow "thunk." For confirmation, check that the tendrils nearest the stem have withered and turned brown, and that the underside of the fruit (where it rests on the ground) has changed from white to a creamy yellow. Cut the stem from the vine rather than pulling.

More: Guides to growing the top summer crops