The low-down on clay soils – Part 1

Beautiful gardens can be grown on heavy clay soils, if you just know how to manage your soil and what plants to grow.

Clay soil can actually be better for gardening than sandy soil, because it retains moisture and nutrients better and the roots get a firmer grip in the soil. It can, however, pose a challenge for even experienced gardeners; for new gardeners it can often be soul-destroying.

A basic understanding of soils and how to manage them are essential for successful gardening, especially for clay soils.

Content of soil

There are three basic sizes of soil particles, sand being the largest, clay being the smallest and silt in the middle.

Sandy soil feels gritty in your hand because the sand particles are comparatively large. When they come together, there are plenty of air spaces between the particles. This is why sandy soils are hungry. They drain very freely and nutrients leach straight through them.

Clay is on the other end of the scale, and particles are tiny. They are also flat and pack down on top of each other, which means clay soils are heavy. Because there is very little air space between them, the soil easily becomes waterlogged.

Silt soil particles are between clay and sand in size. These soils can be difficult to wet when they are dry, or difficult to drain when they are wet. With the addition of organic matter, however, silt soils are quite workable.

Characteristics and contents of clay

Soils with high clay content have a high percentage of fine particles which compact easily, excluding air from the roots and making it difficult for the roots of plants to grow. Clay is slow draining, and extremely small particles tend to pack together, leaving no room for air or water movement.