Clay soil is the most fertile type of soil. It retains moisture longer than other types of soil, which can be a real advantage during a hot, dry growing season. There are a few disadvantages to soils that contain too much clay. The clay particles are very small and can become compacted, inhibiting root growth and oxygen flow. Adding sand to soil with an excess of clay will improve drainage and root-run. According to gardening expert Monty Don, this process will permanently change the structure of your soil and only needs to be done once.
Remove the top 18 to 24 inches of soil from your garden with a shovel, creating a pile nearby. Divide this pile into two equal parts. Haul off one pile in a wheelbarrow and place it in another location.
Calculate how much sand you will need. Plan to replace 50 per cent of your existing soil with an equal amount, by volume, of sand. Using less sand can actually make your soil denser, intensifying drainage problems.
Break up any lumps in your soil pile with a pitchfork. Fork your clay soil back into the garden plot, mixing well with an equal amount of sand in the process. Use the pitchfork to distribute the sand evenly throughout the soil.
If adding sand to a large plot, consider renting equipment or hiring someone to dig out the soil.