Inorganic Materials as Helpful Additions.
It is not always economical or convenient to use organic materials to improve your soil, and there are are other things that work well. Garden stores sell various products useful for loosening heavy soils or retaining moisture and nutrients in lighter ones. Among them are vermiculite, which is made up of particles of puffed mica, and perlite, which is pulverized volcanic stone.
These materials are often used in mixing greenhouse potting soils or for making golf greens. They may be helpful for containers or limited portions of the garden, but treatment of extensive areas becomes rather expensive because you may need as much as 50% in poorly-structured soil.