A raised bed garden by definition is simply one that is elevated off the ground. The bed can be solid to the ground and constructed with sides made of wood, brick, or other materials. The bed can simply be a berm with no permanent edges. Or, the bed can be completely elevated off the ground so that a chair can be placed under it. How you design your raised bed garden depends on your available resources, where you are putting it, and how you intend to use it.