ABSTRACT
As gardeners, most of us are familiar with plants, our chosen ones and the weeds, doing well in one place, but not in another. And in some situations, our preferred plants perform very badly. Often the differences can be attributed to the soil. It can be because of the nutrient problems; these are dealt with in more detail in Chapter 20. Quite often it is simply the physical properties of the soil. Although out of sight, roots play a vital role in supplying water and nutrients to the plant. They must access a large enough volume of soil to supply the plants’ needs and reach a depth that helps to maintain a water supply as the surface layers dry out. Within a full season, a single plant growing well in open ground develops some 500-1000 km of root, with most plants penetrating from half a metre to a metre below the surface. This vast root system is usually more than is required to supply the plant in times of plenty, but the extent of the network is indicative of what is needed in unfavourable conditions. It also serves to remind us of what we undertake to provide when we restrict root growth accidentally in soils or deliberately when we grow in containers (see Chapter 21).
