Along with the soil's nutritional status, its texture will determine which plants will thrive. Plants which require wet soil, for example, will not survive well in sandy soil. For these, the gardener is well advised to amend the soil with organic matter and perhaps a loamier soil to boost the water holding capacity of the existing soil. Conversely, plants which prefer drier conditions will suffer in clay soils. Clay soils are probably the more common problem in the typical garden.
Heavy clay is difficult to work with, compacts easily when it is wet and holds a lot of water.
When dry, it becomes very hard and tends to crack. With a steady supply of light rain, a clay soil will work quite well but in other, more typical, situations, it makes gardening extra challenging. Adding organic matter and sand and mixing it well with the existing soil will help to improve the soil conditions. The organic matter will provide the humus which is highly nutritious, improves the water holding capacity and is of the right texture to allow for proper air spaces. Organic matter will also feed the soil micro-organisms which play a vital role in aerating the soil and making the soil nutrients available for the plants to use.