ARTICLE - What is Clay Soil

Clay soil is a soil which has a heavy concentration of clay particles. The high clay content gives clay soil some distinctive properties which can make it challenging to work with. While this type of soil can be frustrating for gardeners, there are several things which can be done to improve clay soils to make them easier to work with and more hospitable to a wider range of plant species.

The best way to gather information about soil composition is to take a soil sample and have it analyzed. Soil testing will also provide information about the pH balance of the soil, and the balance of nutrients in the soil. Clay soils actually tend to be very rich in minerals, but it can be difficult for plants to access those minerals due to the nature of the soil structure.

Even without a soil test, clay soil is usually easy to identify. It tends to be almost gluey when wet, in addition to very clumpy. When it dries out, it cracks, and the soil has a dense, heavy feeling when felt in the hands. Clay soils are also known as heavy soils, a reference to their density. The problem with clay soil is that the density creates poor drainage, which can be bad for many plants. In addition, it is prone to compaction, and it is often highly alkaline. Many trees and shrubs are able to handle the conditions, but small plants and bulbs are not.

Some gardeners work with clay soils by planting suitable trees and shrubs. Others prefer to add soil amendments to improve the condition of the soil so that they have a wider range of options when it comes to things to plant. Clay soil can be amended by mixing in a deep layer of organic material such as compost, manure, leaf clippings, and so forth. It is important to avoid working the soil when it is wet, as this will cause compaction. If the soil is highly alkaline, gypsum can be added to adjust the pH.

The decision of what to do about clay soil is up to the individual gardener. Gardeners should be aware that it can take several years forsoil amendments in clay soil to work; adding organic ingredients encourages the growth of microorganisms which will improve the condition of the soil, and it takes time for these organisms to get to work in the soil.