Before we go further, we need to talk a bit about soil types, or textures, and a bit about soil structure. Taking a look at the mineral matter in soil, there is a gradation of particle size from microscopic to boulder. These sizes are divided into four categories. The three categories generally considered in soil literature are clay, silt, and sand. It is important to remember that these categories are arbitrary and a gradation.
Soils generally have many sizes of particles, big and small.
The following is a chart that defines the terms used for various combinations of particle sizes. Any extreme, or single soil type, is undesirable. Clay particles are superb sites for cation exchanges, holding nutrients ready for plant uptake, and the small size provides extensive surface for holding water. Unfortunately, clay is extremely slow draining and the particles tend to bind together, refusing to release nutrient cations. Sand drains exceedingly well because the soil particles have much less surface area to hold water, or nutrients for that matter, but completely sand soils need more watering and fertilizing.