|A sample of vermiculite. Photo credit: Brian Pettinger Flickr CC BY-NC-SA 2.0|
Improving water retention in soils begins with understanding the soil type found in the garden. Soils are generally made up of varying mixtures of three sizes of soil particles; sand, silt and clay, known as soil texture.
Generally, water retention is inversely related to permeability. Sandy soils have the lowest water retention, followed by silt, and then soils high in clay.
Various soil amendments are available that can improve water retention, particularly soil high in sand.
These are some of the common and more readily available soil amendments for improving water retention. Each has its own unique benefits as well as limitations.