Soil

The naturally occurring element that garden plants are rooted in. It is made up of several elements including rock that has been broken up or weathered to the point of sand grains or smaller, minerals and organic matter. Many soils get their character from the parent rock that was their main source. The weathering of rock involves not just breaking down the bedrock into smaller and smaller fragments, but chemical changes that occur in some of the minerals of the rock. Generally some rocks break down to produce sandy soils while other types of rock produce clay soils. The process can take centuries. Soil is more than ground up rock. Living organism can greatly modify and improve soil. Good garden soils are a complex community of micro-organisms and includes larger creatures such as earthworms and insects. The living part of the soil does such things as take fallen tree leaves and break them down so their nutrients can be recycled and reused by plants. A rich soil is crawling with biological activity.