Lightweight steel containers are made of steel sheets 1.2 mm thick. The natural oxidation of the surface is chemically accelerated until the desired rust coloration is achieved. The surface patina is then stabilized, and further oxidation is prevented by application of a chemical sealer.  Our steel containers are frost-resistant. Each container has drainage holes and is raised on attached feet to limit contact with the ground surface and to permit air circulation below the container to reduce moisture. Always place your container on a solid-level surface and not directly on grass, soil, or an uneven surface. If a container is to be left planted over the winter, ensure proper drainage. Avoid collection of standing water in the bottom of the container, which can cause rusting and deterioration. If used outdoors, it is recommended that an appropriate sealer is applied to maintain the surface finish and prevent oxidation. If not sealed, the container will darken and rust. If oxidation occurs, rust may leach onto the ground surface with the potential to stain. Natural aging is expected. The use of fertilizers or other chemicals can affect the container’s appearance. Continuous and prolonged exposure to sunlight can cause slight color fading.