Many gardeners face the challenge of working with heavy soil--that is, soil with clay. Clay is impermeable to water and roots, and devoid of most nutrients a plant needs to grow. To successfully cultivate a garden in these conditions, certain steps must be taken to help aerate and fertilise the ground. Breaking up clay soil is hard but simple work.
Till your garden. This is necessary to break up and loosen the clay so you can introduce other materials to the soil. Use a spading fork if the soil is wet, and expose any chunks to the air and sunlight to dry out.
Once the clay chunks have dried out, rake the soil thoroughly. Much of the clods will break apart and you'll be left with much more manageable soil.
Introduce another substance. Using animal manure or compost is an excellent way to provide nutrients, permeability and drainage. If you use animal manure, remember to leech it with water, as it may contain salt that might damage your plants.
Turn the soil and mix the introduced substance with the clay soil. It should be nicely mixed and evenly spread for best results.
Introduce gypsum to your soil. A yearly application for three or more years has been proven to effectively loosen clay soil and improve its quality. Since it doesn't work immediately, it's a good supplement to the compost or manure.
Avoid slow-decaying compost like peat moss, straw or sawdust, as they don't aggregate the soil very well. In large quantities, though, they are valuable as fillers, so you may consider their use in very large gardens. Gypsum is most useful for soils that are sodic or alkaline and have poor structures. It may not be appropriate for other types of soil.
Use caution when working with animal manure to avoid bacteria or other dangers. Wash your hands after touching it or soil containing it. Wear gloves when handling soil to prevent the transmission of other bacteria or viruses.