The Grow Your Own Grub podcast had a couple episodes where water melons were mentioned. As I recall, he had great luck planting some directly into a bag of compost he put on the ground. He slit the top, punched a few drain holes in the bottom, and planted.
revelgardener 
The Grow Your Own Grub podcast had a couple episodes where water melons were mentioned. As I recall, he had great luck planting some directly into a bag of compost he put on the ground. He slit the top, punched a few drain holes in the bottom, and planted.