The four basic types of soil are sand, silt, clay and loam. Loam, considered a perfect soil, is a mixture of silt, clay and sand. Sand is gritty and contains small particles of minerals and rocks, where silt is smoother than sand and is more fertile.
Clay, the most difficult soil to work with, is a fine soil that offers little air space and has poor drainage. Loam is a good soil to use for growing plants because it retains water well and has good drainage. Silt is similar to sand, but it holds moisture better and has more nutrients. Sand is formed by weathering rocks and warms faster than the other types of soil.