Making the Grade: Soil Testing, Part I

In a previous post we discussed the importance of knowing our ecoregions. When we recognize that our ecoregions have a direct effect on our attempts to landscape, we then realize that managing the soils in our care is not as easy as applying a pre-packaged fertilizer program—organic or otherwise. Yet, each year as if by instinct, homeowners and landscapers alike apply soil amendments without knowing what is needed. What is more surprising is that the tool to help them save time, money and successfully manage their lawns and landscapes while minimizing any potential negative environmental impact, is readily available to everyone.

Testing, testing . . .

Soil tests are used to analyze the physical, chemical, and biological characteristics of soil samples taken from a site and processed in a laboratory. Basically, we take samples of soil from the landscape and submit them to a laboratory. The lab runs a variety of tests on the samples and then tells us about the soil. Many agricultural extension offices at land-grant universities provide soil testing services at very affordable rates. Some commercial laboratories provide similar services, but at a higher cost. In either case, submitting soil samples to an accredited laboratory provides us with some very important information about the soil. We can then use this information for our gardening benefit.

No more guesswork

The standard soil test looks at the chemical characteristics of the soil and gives us clues about its nutrient holding capacity. In other words, how much “stuff” the soil can hold onto. Another aspect of this is how much of that “stuff” is available to plants. Although a soil might have all the essential elements a plants needs, one or more might not be available to the plants, due in part to soil pH. Knowing this help us determine if a certain plant species should be considered for the site, and if so, what changes in the soil may be required before planting.

If maintaining lawns or landscapes, a soil test is a useful tool in diagnosing problems. Conversely, a soil test can help us establish better fertility and cultural controls which provide for healthier, more disease and pest resistant lawns and gardens.

In both new and existing landscapes a soil test can help prevent potential environmental problems, such as soil and water contamination from over-fertilization. It can also help prevent unnecessary exposure to toxic elements, such as lead, which can frequently be found in urban soils.

There is a strong relationship among the physical, chemical and biological properties of soils. Therefore, it is important that soil amendments, whether they be mineral, biological or otherwise, be applied only when and where they are needed. Soil tests are the most economical way of determining what is needed; when and where.

Now just imagine what you could do with the time, energy and money saved by using a soil test!