Clayey soils often present landscapers with a serious challenge, because drainage problems go hand in hand with clayey soils. As Steve Jones explains it: "To drain correctly, soil needs something known as 'large pore space.' Soil with a clay content of 20% or more is said to be dominated by 'small pore space.' This means water is slow to move or perhaps won’t move at all, causing the soil to become waterlogged." Learn about dealing with drainage problems in clayey soils in this Plant Man column.