Most earthbag builders buy low cost subsoil and have it trucked to the building site. There are lots of advantages to buying soil, including having the soil dumped right where you need to save labor and speed construction.
But what if you can’t get low cost subsoil or other suitable fill material? For instance, maybe the shipping expense is too great. You could dig a pond to obtain material for the earthbag walls. At the same time, you would also gain potable water storage, and water for irrigation, livestock, raising fish, recreation, fire protection, flood and erosion control, a water garden or to attract wildlife. In addition to all these advantages, building an earth pond also provides a good source of topsoil. Remove the fertile layer of soil as you dig the pond and use it to build up your garden.