Clay soil is composed of mostly clay particles. Soil that consists of over 50% clay particles is referred to as heavy clay. Carry out this simple test to find out if you have clay soil: if the soil sticks to your wellies, garden spade and fork like glue and forms big hard lumps of soil that are difficult to break up and the garden surface cracks up in dry weather, it’s clay!
Clay soil can be a nuisance, even if it’s not waterlogged. Hard clay soil is hard to dig and although many trees and shrubs grow well in clay, the roots of the some annuals, perennials, and vegetables, especially root crops like carrots and turnips can’t grow their way through heavy clay. Clay soil is slow draining, slow to warm up in spring and compacts easily into large hard lumps of soil making it difficult for plant roots to grow. In dry weather the surface cracks up.
Clay soils retain moisture better than sandy soil, handy during long dry spells. It’s also rich in the nutrients plants need to grow, holding calcium, potassium, and magnesium. See the note below to understand a little more about calcium, potassium, and magnesium in garden soil.
It’s possible, with some hard work, to make clay soil more workable and suitable for planting and growing most plants and at the same time keeping the good things about clay such as nutrients essential for plant growth. Clay also has moisture retention properties.