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Do you have information on soil testing?

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As with humans, when a plant is sick, it looks miserable for a while, receives extra water, gets thrown some expensive granules, and is expected to get better. However, when the plant dies, we are surprised at its lack of stamina, then place a new one in the same spot. When that one dies, we scratch our heads and wonder why we have such poor luck with plants. As with humans, there are tests that can be run to help diagnose problems in the landscape. One that is very effective is a soil test. It is the first thing that should be done when problems persist in the landscape. The test analyzes essential components that may cause problems in the soil. It is also a good indicator of how to correct the problem. Here is what a soil test will show.

Texture. The texture of soil is the percentage of sand, silt and clay. This indicates whether the soil is heavy in clay or has a high sand content. Knowing the texture helps determine irrigation needs. It also makes a difference when it comes to selecting plants and deciding which will grow well in an area and which will not. Lime. The lime content of soil is the percentage of carbonates. This is not a problem in northern Utah. We have more than enough lime, and it rarely poses a problem. It is not necessary to add lime to our soils. pH. The pH is a measurement of the acidity of the soil. The pH is a scale from 1 to 14, with 1 being extremely acidic and 14 very alkaline or basic. Most of our soils fall in the range of about 7.5 to 8.5. This is an acceptable range for most plants. Soil test results may be a little higher or lower than that. This information can help in choosing a more acidic fertilizer or other options when amending the soil. Salt. Some soils are high in salt, which can cause plants to be stunted, thin and susceptible to other problems. Salt levels that are too high do not allow the plant’s roots to absorb water properly. Not correcting the problem can lead to perennial problems and frustration. Phosphorus. Most soils in Utah have sufficient phosphorus, but occasionally they are slightly deficient. A soil test indicates how much to apply to supplement plant needs in the landscape. There are often more soils with excess phosphorus than not enough. Knowing that levels are high can be beneficial so you can discontinue applying it to your soil. Potassium. This is another element that is normally abundant in our soils. However, it can become deficient, especially if the topsoil is removed when a new home is built. These are the basic components that are addressed by a soil test. Knowing the amount of these elements in the soil will not solve all plant problems, but will provide a good place to start. A basic soil test kit can be picked up at any Extension office. The kit is free, and the cost of a routine analysis is $14. It is worth the investment to learn how to solve or avoid soil problems.

Posted on 1 Apr 2006

Jerry Goodspeed
County Director, Horticulture Agent, Weber County

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