Q: A friend of mine said my garden has clay loam soil. I am not sure if he meant it in a good way or not. Is clay loam a good soil for a garden?
A: Soil is made of three major components. They are minerals, water and air. Without the pores that allow water and air movement, the soil will not support many plants.
The mineral components of clay, sand and silt are combined in various percentages. Imagine a triangle with clay at the top, sand in the lower left corner and silt in the lower right corner. If you had a soil of 100 percent clay, the top of the triangle would be highlighted. If it was around 50 percent sand and 50 percent clay, the middle of the left side would be highlighted. Scientists call soil made from all three components loam. If it has more clay than a good loam should have, it would be a clay loam soil. It is not a bad soil. In fact, most people would love to improve their soil so that it is a clay loam. If you think there is too much clay, adding some organic matter will help break it up.
You can have your soil tested at a soil laboratory, but you can do some testing yourself. Take some soil in your hand and rub it between your fingers. If it feels gritty, it has a high sand content. Clay particles stick together and allow you to mold the soil into little snakes, just like a little kid might do. Silt particles are slippery, too, but they feel like talcum powder or flour when the soil dries out.
If you put some soil in a jar with water and shake it up until it is thoroughly mixed, you can see the various percentages of these ingredients. The sand will settle out quickly, and the silt will settle out next, while the clay may take several days before settling out.
Sandy soils drain quickly and do not hold nutrients very well, because the sand particles do not hold on to the nutrients and the water washes them away. Sandy soils have lots of air spaces between particles but very little water-holding capacity. They are good for growing many kinds of plants that need good drainage and lots of air in the soil.
Silt particles are much smaller than sand, and therefore, the air spaces between particles are much smaller. Smaller pores mean slower water movement, more water-holding capacity and fewer nutrients washing away.
Clay particles are thousands of times smaller than grains of sand. They are sort of shaped like paper dinner plates. When the particles get smashed together (compacted), they arrange themselves like a stack of plates with almost no room between them. Therefore, clay soils have very small pores and allow very, very slow water movement. Because of their electrical charge, many nutrients stick to clay particles, but they may also have difficulty coming off when a plant needs them.
Clay particles can swell when wet and shrink when dry, causing many problems. If a hole is filled with dry clay, like a hole around a basement foundation, the clay will swell when wet and may crack the walls. If it is added to the hole when wet, it will shrink when dry, leaving big cracks. Cracks can break tree roots, causing even more damage than dry weather by itself.
You might think that the best way to fix a clay soil is with sand and the best way to fix a sandy soil is to add clay, but that can have very bad consequences. Sometimes that combination forms a type of concrete. The best thing to solve the problems is the addition of plant organic matter.
Sandy soils benefit because the organic matter clogs up the loose pores of the sand and holds a lot of nutrients. Clay soils benefit because the organic matter does not allow the particles to slide together into sticky lumps.
Virtually any organic matter will do. At this time of year, many people have access to lots of leaves, but peat moss and manure will do, too. Mix about one-third organic matter to two-thirds existing soil.
Email questions to Jeff Rugg at info@greenerview.com. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.
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