Juicy, sweet watermelon is truly a summer treat. Watermelons require a long, hot summer in order to reach maturity. In the areas with short summers, start watermelon seeds indoors and transplant outside after all danger of frost has passed. In areas with a long summer watermelon can be started right in the garden bed. Germinating and then growing the seeds into the melons is not challenging but does require ongoing maintenance throughout the season for a successful harvest.
Fill individual seed starting containers with potting mix to start seeds indoors three weeks before the final frost date in your area. Moisten the soil before planting the seeds.
Sow two seeds per container for standard watermelon varieties or one seed per container for seedless varieties. Plant seeds 1 inch under the soil surface in the center of the pot.
Cover pots with plastic wrap and place in a warm room to germinate—approximately 75 to 80 degrees Fahrenheit. Check daily for sprouts and to ensure the potting mix is still moist. Watermelons usually take 7 to 14 days to germinate but check seed package for exact timing for the variety you are growing.
Remove plastic wrap once sprouts appear and move pots to a warm, sunny window. Keep potting medium moist at all times and do not let it dry out—watermelons require a lot of moisture to grow properly.
Transplant into weed-free garden beds once all danger of frost has passed and seedlings have produced their second set of leaves. Plant outside 3 feet apart in rows that are 7 feet apart.