Watermelon Growing GuideUpdated 12 days ago

Watermelons are warm-season fruits that thrive in sunny, spacious areas with plenty of warmth. Here’s how to successfully grow watermelons:

When to Sow

• Outdoors: Sow watermelon seeds after the last frost, when soil temperatures are above 70°F.
• Indoors: In cooler climates, start seeds indoors 4-6 weeks before the last frost and transplant once outdoor temperatures are consistently warm. For more details, check out this guide on watermelon planting.

Outdoor Sowing

• Choose a sunny, well-drained location with fertile soil.
• Sow seeds 1/2 inch deep, spaced 4-6 feet apart in rows or hills.
• Keep soil moist until germination, which takes 5-10 days. For information on preventing diseases like fusarium wilt, visit our watermelon disease guide.

Indoor Sowing

• Use biodegradable pots to avoid disturbing the roots when transplanting.
• Sow seeds 1/2 inch deep in seed-starting mix, and keep the soil warm (80-85°F).
• Transplant seedlings outdoors when they have two sets of true leaves and conditions are favorable.

Care & Maintenance

• Sunlight: Watermelons need full sun for optimal growth.
• Watering: Water consistently, especially during flowering and fruiting. Avoid overhead watering to prevent fungal diseases.
• Mulching: Mulch around plants to retain moisture and suppress weeds.
• Fertilizing: Apply a balanced fertilizer when the vines begin to run and again when the fruit starts to set.

Pests & Diseases

• Common pests include aphids, cucumber beetles, and squash bugs. Use row covers for young plants and insecticidal soap for infestations.
• Watermelons are prone to diseases like powdery mildew and fusarium wilt. Ensure good air circulation and avoid overwatering. For more help with pests, refer to our watermelon pest guide and watermelon disease guide.

Harvesting

• Watermelons are ready for harvest when the tendril nearest the fruit dries out, the ground spot turns yellow, and the fruit gives a deep sound when tapped.
• Use a sharp knife or pruners to cut the fruit from the vine. For more tips, check out our watermelon harvesting guide.

Garden Use

• Watermelons need large spaces or raised beds due to their sprawling vines. They grow well as companion plants with corn and sunflowers, which can provide some shade for the fruit. Learn more about watermelon companion plants here.