Betta Pond Plant Baskets are made from black plastic with meshed sides. These mesh sides allow water into the roots of the plant enabling them to obtain the nutrients that they need. It is best to line out the basket with hessian (YD050 Pond Plant Basket Hessian Squares) to prevent finer soil from falling through. After planting, top-dress with gravel to discourage fish from disturbing the plant roots.