If you enjoy the fresh taste of ripe watermelon still warm from the sun, but don’t have the growing space available in your yard, then growing watermelons in a container may be an option. To plant watermelons in a big pot you’ll want to select a dwarf variety such as Bush Sugar Baby or Garden Baby and have a large-enough pot to support it. After planting, you’ll need to keep the plants well watered and fed to get the best, largest watermelons possible.
Layer the bottom inch of your pot with small gravel. Cover the gravel with clean potting soil and fill to within an inch of the top.
Plant three dwarf watermelon seeds into the center of the pot, 1 inch deep; plant them 3 inches away from one another. Cover over the seeds lightly with soil. Be sure the pot is set in an area that receives full sun—at least six hours of direct sunlight each day.
Water the soil in your pot well and keep it damp, but not soaked, as the seeds germinate over the next two weeks. When the seedlings are 6 inches tall, thin out the weakest one, leaving two plants to grow in your pot.
Feed your seedlings with a high-nitrogen fertilizer—10-0-0 strength—with a liquid fertilizer or granules. Feed the watermelon each month to encourage good growth and fruit production.
Water the watermelons two to three times a week to keep the soil moist inside the pot. The larger your plants become, the more water they will use, so regular watering is crucial to growing successful watermelons.
Allow the vines of your watermelon plant to cascade over the edges of the pot as it grows larger. Make sure your pot is in a location where there is room for the vines to grow and not be cramped or blocked from sunlight.