Watermelon, a staple of warm summer days and picnics, is an easy-to-grow, warm-season melon. According to the University of Illinois Extension Service, watermelons can be grown in all parts of the country, but grow best in the warmer temperatures and longer growing season of southern areas. Check the seed packet to make sure your season is long enough for your watermelons to mature. Once you choose your variety, planting watermelons is quite easy.
Prepare your soil before planting. Amend with compost or sand to lighten clay or acidic soil; watermelons prefer a light loamy soil that is well drained. Seeds do not germinate well in cold soil, so wait to plant until all chance of frost has passed and the soil has warmed up to at least 70 degrees F. According to the Oklahoma Cooperative Extension Service, seeds will not germinate at soil temperatures below 60 degrees F, and the most rapid germination occurs at 95 degrees F.
Plant seeds in rows 6 to 8 feet apart. Place your seeds 5 to 6 feet apart in the row to give them plenty of room to spread. Cover lightly with about 1/4 inch of soil.
Water the rows gently. Once the plants are established, water frequently, preferably with drip irrigation to keep water off the foliage and avoid foliar diseases.