The Corten Steel from Idealist is a beautiful, low maintenance outdoor planter. The steel is designed to "weather" or "age" to give a coppery colour that will improve with time. Starting out as a blue/grey colour, as soon as Corten Steel is exposed to the elements, it will naturally weather and develop a rich eye catching finish. This natural fixed coating of rust provides protection against further corrosion. After the initial reactive period, Corten Steel will cure and self-seal with little to no carbon run off. During the weathering process the Corten Steel produces carbon run off which can stain adjacent materials such as stone or concrete. Please note this product will start its dense chemical composition once received, at any point and throughout the weathering process. Corten Steel Weathering Process Once placed outside, the Conten Steel will immediately start its weathering process. Typicaly Corten steel will have a reactive patina period around 3 to 9 months. So when you receive your planter, the initial colour will be un-weathered or partly weathered. Starting out as blue/grey, heavily coated steel will begin to break down depending on the weather conditions and planters position in your garden. In it's final stage, Corten Steel will develop its beautiful aesthetically pleasing finish.