Compost is a nutrient-rich material that can be used to improve any type of soil. It can be made from a variety of organic waste products, including kitchen scraps, manure and yard waste. Compost is generally kept in outdoor bins, where it's given time to decompose before being applied to the garden. As it decomposes, the levels of plant-friendly nutrients in the compost are increased even further. Even after it's applied to the garden, the compost continues to break down, giving it a much longer-lasting impact than fast-acting chemicals and fertilizers [source: Stell].
Compost will improve plant growth in nearly any type of garden. In loose, sandy soils, compost helps to bind the soil together to retain moisture and nutrient levels. In denser soils like clay or silt, the compost reduces compaction to increase air and moisture flow to the roots. To provide maximum benefit, the compost must be mixed in with the existing topsoil layers. Plan to use about 4 to 6 inches (10.2 to 15.2 centimeters) of compost per 6 to 12 inches (15.2 to 30.5 centimeters) of soil [source: City of Bremerton].
In areas with poor drainage, consider using equal amounts of commercial topsoil and compost to create raised planting beds above the existing soil. This will allow excess moisture to flow down below the root levels, which can keep plants growing successfully.