Dig a basin 1 1/2 feet deep. Dig out topsoil, rocks and weeds.
Dig deeper to remove more soil, but use this to build a berm, or raised bank, around the border of your basin.
Combine one part compost to each four parts of topsoil. Use other organic materials, such as leaf litter, grass clippings, animal manure or peat moss if you wish. Transfer the mixture back into the basin.
Rake the top of your sunken basin garden bed to make it level. Plant vegetable seeds or starter plants in the bed according to their needs for space. However, with this method, plant more closely than you would in regular beds.
Irrigate your sunken bed with standard methods such as sprinklers, or set up a drip irrigation system for maximum efficiency and increased water conservation.