Because growing watermelon is so easy, it's one of the best beginner's garden projects. A few baby watermelon plants, a plot of dirt and lots of sunshine is all it takes to make you feel like a horticultural genius. Plan to start your watermelon in the garden late in the spring when the temperature has been between 60 and 70 degrees Fahrenheit for at least a week. Your watermelon should be ready to harvest within 70 to 85 days.
Choose a sunny, warm area of the garden where the watermelon will have a lot of room to spread.
Prepare the planting site by using the shovel to dig down about 10 inches into the soil, turning it and breaking up any large clods of dirt. Add a 2-inch layer of rotted manure, a 2-inch layer of compost, and a 2-inch layer of coarse sand to the soil and use the rake or shovel to mix well. Level the soil and water well, allowing it to drain fully.
Dig a hole in the soil twice the width and depth of the pot in which the plant is currently planted. Remove the watermelon plant and place it in the hole, and backfill with soil. Press the soil around the base of the plant. If you are planting more than one watermelon plant, space them at least 6 feet apart.
Water the plant only when the weather is exceptionally dry.
Fertilize the watermelon plant according to the following schedule. Apply a fertilizer high in nitrogen until the plants start forming flowers. Good organic sources of nitrogen are animal manure, fish and bone meal. Once the watermelon plant is blooming, use a fertilizer high in phosphorous and potassium.
Inspect the watermelon plant frequently for pests. Cucumber beetles, aphids and mites are some of the insects that are attracted to watermelon. Insecticidal soaps and horticultural oils such as those containing neem can help certain infestations. For questions concerning pests in your region, contact your cooperative extension.