Soil as a Growing Medium

The plant takes up water and nutrients from the growing medium through is roots, which also provide anchorage (see root structure). The root also requires a supply of oxygen and produces carbon dioxide, which is harmful if it build up in the root zone (see respiration).

In order to secure water throughout the season the roots penetrate deep into the soil. The plant nutrients are extracted from a very dilute soil solution and so the roots are normally very extensive and with a shape that bring the maximum absorptive surface into contact with soil particle surface around which is the water and nutrients. Within one growing season a single plant growing in open ground develops some 700 km of root, which has a surface area includes the root hairs.