A plant with yellow or wilting leaves may have a problem around its roots. Soil supplies anchorage, water, air and nutrients, and is a habitat for living organisms. Leaf appearance alone does not tell you which part has failed.

Think of a sponge: solid material gives it shape, while spaces hold air and water. Soil has a mineral and organic framework with pores between its parts. The proportions vary; the soil diagram is an illustration, not a test of healthy ground. Most garden roots need oxygen for respiration as well as access to water.

Look at the root environment alongside light, weather and plant condition. Good soil management helps, but it does not make the rest of plant care automatic.