Watermelon is a staple at summer picnics and an annual Fourth of July tradition for many families. The juicy fruit is a thirst-quencher and can hit the spot on a hot summer day. Depending on the variety you choose, it takes between 70 and 100 days to be ready for harvest. When a watermelon is ripe, the curly tendrils near the stem will begin to brown, according to the University of Illinois Extension.
Plant your watermelons in well-draining soil in a hot and sunny spot. Watermelons are a warm-season plant that grows best in warm temperatures. Ideal conditions are daytime temperatures between 70 degrees F and 80 degrees F and nighttime temperatures of 65 degrees F to 70 degrees F, according to the Ohio State University Extension. However, they can be grown successfully when the daytime temperature is higher than 65 degrees F.
Watermelons should be planted in the spring when the threat of frost has passed for your area. If you are planting several watermelon seeds, you'll need a sizable patch of land. Plant two or three seeds a 1/2 to 1 inch deep in hills that are spaced 6 feet apart, according to the University of Illinois Extension. Rows of plants should be spaced 7 feet to 10 feet apart. Once the seeds sprout, thin out the plants so only one watermelon grows in each hill.
You can also start watermelon seeds indoors and transplant them outdoors after the threat of frost has passed. Seeds should be started three weeks before it is safe to transplant them. Plant two or three seeds in a seed-starting pot or a peat pot. Place the seeds in a warm location, preferable between 80 degrees F and 85 degrees F. Check the seeds regularly and water as necessary to keep them moist. Once the seeds sprout, thin them out so only one plant remains in each pot. The seedlings can be transplanted outdoors once the threat of frost has passed.
Beds of watermelon plants need to be kept free of weeds and other plant growth. Placing plastic mulch around the plants can help prevent weed growth and also keep the soil warm and help the plants conserve moisture, according to the University of Minnesota Extension.
Watermelons need between 1 inch and 2 inches of water per week. Water the plants during prolonged dry spells so the roots do not dry out. As the watermelons begin to ripen, you can cut back on the watering to help improve the flavor of the melon. In the final two weeks of maturation, avoid overwatering because it can cause the melons to split open, according to the University of Minnesota Extension.