Plant watermelon seed or seedlings about 6 inches in from the edge of the barrier and just about 1 inch down. Apply a layer of hay to keep the plants protected from the damp ground and to discourage weeds. Harvest the watermelons when the stems start to brown and the melon has a hollow sound when it's thumped.

To sow seeds directly outside, form six-inch high raised beds in the dirt. Plant the seeds a half-inch deep and 20 inches apart. Sow two to three seeds per section and thin the seedlings after they emerge. Water the seeds and seedlings right after planting and position a trellis near the plants to grow melons to grow off the ground.