Add sand to loosen heavy, clay soil?

The worst remedy for a clay soil is to add sand. This practice turns the clay soil into a rock-hard, mortarlike substance. Instead, use organic matter, like compost, to loosen heavy soils because it is light in composition and also improves nutrient quality. Sand can improve a clay soil, but it must be added until it constitutes most of the mineral composition of the soil. At that point, it’s not really clay soil any longer; it is sandy soil.