Clay soil curses most gardeners in the South. It drains poorly, dries hard as a rock, and restricts the movement of air, water, and plant roots. It's a pain in the butt to garden in. So naturally, we look for things we can add to it to loosen it up and save our aching backsides.
A lot of people think you can loosen up clay by mixing in lots of sand. It's sounds logical. After all, among all the constituents of soil, clay particles are smallest and compact the most, while sand particles are biggest and compact the least. Adding lots of sand will therefore break up that clay, right?
Wrong, wrong, wrong, rototiller-breath! Sand mixed with our Southern clays forms a sort of nasty concrete. When it dries, just try digging in it. You can jump from a tree onto the shovel blade, but the blade won't move and you'll lose your dentures.
Instead of adding sand, add organic matter -- lots of it. Any kind will do -- sphagnum peat moss, garden compost, composted cow manure, grass clippings, chopped up leaves, chopped pine bark, potting soil, worm castings, whatever. Organic matter coats the clay particles, opening up pores in the soil through which air, water, and roots can freely move. It also makes the soil comfy for earthworms and other organisms that loosen the soil even more.
So forget sand. Add organic matter to your soil every year, in gross quantities if you can. Organic matter can turn even the worst clay soil into good soil within a couple of years.
The Grump hath spoken!
Photo by Jared.