What is Sand, Silt and Clay?

Sand

Sand is small, coarse-grained pieces of rock. You can see and feel the individual pieces. Sand feels gritty. It does not stick together or form clods or peds. It can be really fine or not so fine. Not much surface area is exposed. Sand increases space between particles, which means air and water can move more freely, and this means sand is needed in soil to provide good drainage.

Sand

Silt

Silt is very soft and could be described as powdery. The particles of silt are so small that you would only be able to see them with a microscope. Water soaks into silt easily. Silt will form into clods or peds that crumble when they get wet. Silt particles do not stick together. Soils that are said to have good water holding capacity will be high in silt.

Silt

Clay

Clay is even finer than silt. Clay particles are described as platy and thin in shape. They fit closely together. Clay sticks together very well and will form clods. Soil that contains a great deal of clay would be described as heavy. Clay has a large surface area because the particles are small. The amount of clay in a soil has a great impact on the soils water holding capacity.

Clay

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