The classification of soils into sand, loam, and clay is determined by the percentage of mineral matter, such as sand, silt, and clay particles, in the soil.
Sand particles are the largest and feel gritty when rubbed between your fingers. Loam is a mixture of sand, silt, and clay particles, and has a crumbly texture. Clay particles are the smallest and feel smooth and sticky when wet.
Soil texture, or the relative proportion of sand, silt, and clay, is a major factor in determining a soil's ability to retain water and nutrients, and its suitability for growing different types of plants. For example, sandy soils drain quickly and are low in nutrients, while clay soils are slow to drain and may become compacted, reducing the amount of air and water available to plant roots. Loam soils have a good balance of water and air holding capacity and are considered ideal for most types of plants.