Gardening In Heavy Clay SoilClay soil is usually sticky and hard to work with because clay particles are tiny. These particles are less than 1/12,500 of an inch in diameter and are so small that that they pack very closely together. Because the particle size is so small, clay has the greatest total surface area by volume. They are also capable of retaining the most water and the greatest concentration of the nutrients that plants need to grow. Their density also helps them retain the nutrients that would be washed or leached away through lighter soils. Clay is so dense that air has difficulty getting to plant roots. Drainage in clay soils is often a problem. Plants can drown or suffocate for lack of air. And, when it finally dries out, it can get as hard as cement. The good news is, you don’t have to water the lawn or the garden as often. I gardened for years in a heavy black clay soil. That soil type was so prevalent in our area, that our part of the valley was called the “Black Sticky”. Because of high nutrient levels, it would grow things well, but it was very hard to work. We used to call it "30 minute" soil, meaning you had about 30 minutes every spring between the time it was too wet to work and too dry and hard to work. It wasn’t quite that bad, but nearly. Some crops do well in heavy soil. They grow a lot of pears commercially in my area. Pears like heavy soils, and don’t mind their roots being on the wet side. So they are well suited for our area. Clay soil comes in black, red, brown, grey or yellow, depending on the type of minerals that they contain. What they all have in common is particle size. That’s what makes them clay. Improving Clay SoilsFor better gardening, this soil type must have better drainage, more air circulation and be less prone to pack so tightly. The fine particles in clay must be mixed with courser material that will prevent it from binding so tightly. There are several ways of amending it.Gypsum will bind with it and make it more friable, and the calcium and sulfur in the gypsum are also helpful for plant growth. It makes a good soil amendment. You can buy agricultural gypsum at most garden centers and at feed and fertilizer stores. Sheet rock scraps can be a free source of gypsum. Break it up and till it into your garden. You could add sand to your garden, but it will take an awful lot. To get to a loam consistency, you would have to add about 50% sand to the volume of soil in your garden to a depth of 8-12 inches. That would mean as much as 23 cubic yards of sand to a 25ft x 25ft garden. That would cost a fortune and would only work when the clay was very workable or the sand would not mix in well. A better, cheaper solution is to add organic matter on a continual basis. The type, amount and method of adding that organic matter is discussed here. Higher Organic content will greatly increase your drainage, and provide needed aeration to plant roots. Gardening in clay soil is tough, even for a garden gnome, which is why back in my “Black Sticky” days I became a convert to raised bed gardening and soil recipes. Happy gardening, Geefrank
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