Your soil type determines which plants you can grow, and knowing your soil type enables to you to choose the plants best suited to your garden. Soil type is identified the presence of clay, sand and silt. The ideal soil (loam) has equal amounts of all three, which make a fertile, free-draining soil that's easy to dig.
There are six main types of soil: chalky, clay, loamy, peaty, sandy and silty. To test your soil, take a look at it and feel it. Add water and try rolling it between your hands. Observe how your soil looks and feels, and whether it's sticky, gritty, friable, or slimy.
Heavy soil – such as clay soil – is made up of small particles, which bind together easily, making the soil prone to waterlogging. Light soil – such as sandy soil – is made up of large particles, so is free draining and prone to leaching nutrients. You can improve soil by incorporating organic matter, such as manure or home-grown compost. It helps bind large particles together, helping retain moisture, but also increases the size of smaller particles, aiding drainage. Grit or sharp sand will also aid drainage of heavy soils.
Depending on the size of your plot, test the soil from different areas, as it can vary enormously. If possible, create main planting areas where the soil is good, saving poorer conditions for hard landscaping, where soil quality is less important.