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Soil - Part I - Types of Soil

© Marge Talt

Soil is the material that covers the earth's crust. It's made up of minerals and organic matter in various combinations, plus liquid (water) and gas (oxygen). Since it is possible to grow plants without soil, I think it's fair to say that soil is second in importance to light in the life of a plant. That's not to say the state of your soil is not important, because it is extremely important. What type of soil you have is one of the first things you need to find out about your garden.

So, what kinds of soil are there? From the gardener's viewpoint, which is more simplistic than a geologist's, there are three basic types: Sand, clay and loam. Strictly speaking, I should say: Sand, clay and silt. For more detailed descriptions of these soil types as well as a method of determining what type of soil you have, check out some of the web sites and articles on my Links list. There are also areas with peat soils, muck soils and adobe or gumbo soils.

Sandy soil is coarse, free draining and, generally, nutrient poor.

Clay soil is fine textured and holds moisture longer. Clay is difficult to work when wet and dries to a concrete-like substance that can only be penetrated with a pick ax.

Silt is slightly less finely textured than clay. It is intermediate between clay and sand. A pure silt soil can, however, become almost as hard as clay when it dries out too much. I learned this the hard way when I let myself be talked out of additional coarse sand in a truckload of topsoil I ordered. The company kept saying it was already sandy enough! What it actually was, was silt. Lovely to look at, rich and smooth, but, when it dries out, it is just about impossible to work.

Loam is the gardener's dream. It is can vary from sandy loam to clay loam, depending on the percentages of sand, it contains silt and clay.

Peat soils are usually those from peat bog areas and are basically sterile. They may look marvelous, but will not provide your plants with any nutrients. They are good soil conditioners, particularly if you want to grow acid-loving plants.

Muck soils come from dried up bogs where not enough time or plant remains have been available to form peat. Muck soils can be used for growing plants, but you should check with your local state extension agent before you use them, since they are not all the same.