A large pond can transform a garden, adding a spectacular focal point and enormous benefit to wildlife. A natural pond is achieved by creating gently sloping margins and if a liner is required, covering this with a 300mm layer of soil material so that no liner is left exposed. A inert material with low organic content such as the excavated subsoil from excavating the pond, gravel or stony material is ideal for this, reserving topsoil for the planted margins. This allows a natural ecosystem to develop that will self-regulate with the right balance of pond planting, with minimal maintenance.