Which color indicates well-drained soil?

Well-drained soil typically exhibits a brown color, which indicates good aeration and a healthy balance of organic matter and minerals. This brown hue generally results from the presence of iron oxides that occur when soil has sufficient drainage, allowing oxygen to interact with the iron. In well-drained conditions, the reduction of iron is minimal, contributing to the bright and rich brown colors.

Other colors, such as gray or grayish, might suggest poor drainage or waterlogged conditions. Gray soils can indicate saturation and reduced conditions, where iron compounds are reduced due to lack of oxygen, often leading to mottling as iron redistributes in response to fluctuating moisture levels. Therefore, brown is a reliable indicator of well-drained soil that supports good plant growth and healthy root systems.