Tips to better understand soil test results

Q. Help! I can’t understand my soil test results. What do I add to make my soil better?

Lillian from Youngstown

A. It simply depends on the results of the test.

While all soil tests give basic recommendations, they are somewhat difficult to decipher if you don’t review these on a regular basis.

Our clinic volunteers will help interpret soil tests over the phone or in person. Sometimes this is the best way to understand the details of the results.

The most important part of the test is the pH. Most garden and landscape plants prefer a pH of 6.2 to 6.5.

Several tests we receive have a pH higher than that amount. One of the main reasons is the over application of lime to the soil. This is an old practice that worked when we had more coal-burning facilities here in the valley. The acid rain reduced soil pH over time, thus many people added lime to counter the effects. This is not a big factor anymore.

For those with high pH levels, an application of sulfur is necessary to reduce the soil pH. Sulfur is available at some local garden centers and online retailers. Usually, the amount needed is small. Many times, a sulfur application is required for plants that need lower pH levels. This includes azaleas, rhododendrons, and blueberries to name a few. Listing details about what plants are going to be planted will help the soil testing lab give you the best recommendations for soil improvement.

Fertility is the most often reviewed part of the soil test results. Nutrient levels are a major concern now, especially when it comes to phosphorus.

If the results say not to add any fertilizer – the recommendations need to be followed. But there are cases when phosphorus is needed.

Soils around the home were disturbed when the home was constructed. Sometimes the top soil was stripped away and some subsoils are now on the surface. In these cases, phosphorus may be low.

Usually, a one-time application based on the recommendations will fix the issue. Only a soil test will tell you what to do. Even if your home is older, a soil test may never have been completed and thus the nutrient levels might not have been corrected. For any fertilizer application, be sure to read and follow all label directions. Too much fertilizer is not a good thing.

The main thing to know about soil tests is simply keep doing them every three years. Don’t guess, soil test! These tests will save you time and money in the garden. To learn more about soil testing, visit: http://go.osu.edu/soiltesting.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Winter hours for the Plant and Pest Diagnostic Clinic vary. Submit questions to the clinic at 330-533-5538 or drop samples off to the OSU Extension Office in Canfield.