Can I use sand to break up clay soil and improve my lawn? -Gary
Sand is an important ingredient in the composition of soil (see What Is Dirt, Anyway?), but it needs to be balanced with organic matter in order to be of any benefit. Despite popular advice, you shouldn’t use sand by itself – that misguided practice is a cheap shortcut rather than a problem-solver.
When mixed together, sand and clay form a substance very similar to concrete, which will make your problem worse! Your soil would have to be more than 50% sand before it would start behaving like sandy soil – and sandy soil has drainage problems of its own.
You’re better off mixing your sand with compost or humus, at a 50-50 ratio, before incorporating it into your soil. Use the coarsest sand you can find (not play sand), with the largest particles, and mix it with well-rotted organic matter. If you aren’t able to do this step, you’re better off using compost alone.