The size of particles that make up a soil and their proportions relative to each other. The particles in soil are graded according to their diameters in the following way:

Heavy soils are in high clay content. Light soils are high in sand content.

Clay soils retain more moisture than others, as they are made up of very small particles: a kilogram of clay will contain a much larger surface area for the adsorption of water than a kilogram of sand. Clay soils will also hold more minerals, as the particles are negatively charged.

But clay soils have several disadvantages:

• Take longer to heat up in spring and tend to be colder all the year round.
• Swell when they absorb water and shrink when they dry. This can cause severe cracking.
• As clay becomes wet, it becomes very sticky.
• If clay soils are worked when wet, their structure can be severely deteriorated.

The ideal soil texture is loam, which combines the nutrient-holding features of clay with the good drainage of sand. Soil textures can be assessed by feel.