The Knox Planter (2021) gives you a choice of the rustic patinated look of Corten steel, or a clear or coated finish that’s maintenance-free. Corten steel planters will patinate over a period of three to nine months, depending on location and climate. Linen, Deep Space, and Clear Coated planters arrive fully finished with a coated exterior and will not develop a patina. Note: If you choose Corten steel, use the planter in a garden or lawn area during the patina period, as the carbon runoff can stain materials like stone and concrete.