To prepare the ground for a pond liner, start by digging out the pond shape to your desired depth and contours, creating ledges or shelves if you plan to place plants at different levels. Once the pond shape is excavated, remove any sharp rocks, roots, or debris from the bottom and sides to prevent damage to the liner.
After clearing the area, level and smooth the soil to create an even surface, as this will help the liner sit properly and reduce stress on the material. Adding a layer of sand, about 1–2 inches thick, over the entire pond base smooths any irregularities in the soil, such as smooth embedded rocks, and further protects the liner. For additional protection, lay down a non-woven geotextile underlayment or pond-specific liner underlay, which cushions the liner from punctures and helps prolong the liner’s lifespan.
