Some mixes are better than others, and the grower is responsible for using the most appropriate growing medium available for operations. Chemical characteristics include pH, cation exchange capacity, electrical conductivity, and fertility. This article will discuss only the physical characteristics of soil. Texture and structure affect air porosity and water retention. Two important soil characteristics are texture and structure.
Texture affects water retention and, consequently, air porosity.
Smaller pores present higher resistance to water flow, which in turn increases water-holding capacity. The size of the particles and their distribution determine texture. Clay is comprised of smaller particles, while sand is comprised of larger particles. Mixing components of varying particle size dramatically affects air porosity. Mineral soils tend to have smaller particles.