Garden soil is a mix of differently sized rock particles. Depending on the prevailing dominance of one particle size over another in your yard, you may identify your soil to be heavy on silt, sand or clay. Each soil type has advantages and disadvantages; endemic to clay soil is the lack of sufficient minute openings between particles that would allow for drainage and aeration. On the flipside, its benefit is the high concentration of minerals and trace metals that allow for optimum plant growth. Learning how to loosen hard clay soil for a garden lets you tap into these beneficial resources and offer your plants a chance for strong root growth and adequate nutrient uptake.
Break up your hard clay soil with a rototiller. Set the tines to dig down deep--about one foot. Repeat this process until you've managed to break up all bigger lumps of clay.
Work washed sand into the clay soil. It aerates the soil by introducing larger rock particles into the ground and forcing them in between the much finer clay specks. A standard amount is one cubic yard of sand for every 100 square feet of clay soil. Adjust the amount of sand to suit the makeup of your clay soil. The heavier the clay, the more sand you need to add.
Add two to four inches of organic matter to the soil mix and work it in. You may choose peat moss or compost. Peat moss enables the soil to better store moisture, provide oxygen and offer plant roots the vital nutrients they need to thrive. Compost additionally introduces beneficial microbes into the soil and also affects its acidity.
Establish walking paths between flower beds to protect planting areas from compaction. Soil compaction is a continuous danger when working with clay soil. Even after amending the soil and providing aeration, walking over areas you plan on planting in may once again lead to compaction.