Basic Gardening Techniques: Understanding Your Soil
The type and condition of theis one of the most important contributory factors to successful gardening. Soil conditions not only determine the kinds of plants you will be able to grow, but also the amount of time and trouble that you will need to spend in growing them.
It is better to choose plants that suit your soil than to try and change the soil to suit your plants. The latter procedure is seldom worth the considerable effort involved, since there are so many plants worth growing that will flourish in widely differing soil conditions.
Soils range from heavy clays, in which the soil particles are so small that they bind together into a sticky unworkable mass in wet weather, to light sandy soils, whose larger granular structure makes them easy to work under almost any conditions. Chalk soils pose difficultproblems and the subsoil, often consisting of solid chalk, will need breaking up to 60 cm (2 ft) or more deep.
With the exception of chalk, which is always alkaline, soils also vary in their degree of acidity or alkalinity. This is measured by what is known as the pH scale. The neutral point on this scale is pH7, which indicates that the soil is neither acid nor alkaline. Readings below pH7 indicate an acid soil (the lower the pH value, the more acid the soil), while those from pH7 upwards indicate an alkaline one (the higher the pH, the more alkaline the soil). The optimum soil conditions for the majority of garden plants are slightly acid – from pH6 to pH6.5.
Soil-testing kits are obtainable from most garden shops and centres or direct from the manufacturers, who often advertise in gardening magazines. Kits range from simple inexpensive kinds to more elaborate ones which, as well as registering the pH factor, indicate any trace elements and fertilizers that are lacking and specify the amounts needed to make good the deficiency.
Soil-testing kits are a worthwhile investment, because they will save you much frustration and unnecessary work in trying to grow plants that are not suited to your soil conditions. Plants grow much more healthily in the right conditions and this in turn makes them less susceptible to pests and diseases.
Although soils are usually described as belonging to just one of the categories mentioned above (clay, sand, chalk), most garden soils are really a mixture of several types -especially if the plot has been under cultivation for a long time. In larger gardens, too, you will sometimes find different soil types in different parts of the plot. In my own garden, for example, which generally enjoys the benefits of a light acid loam, there is an area of heavy unmanageable clay where the subsoil was excavated for an ornamental pool when the garden was first laid out.