Jeffry Hill is a professional agronomist and soil expert.
Testing a soil is a smart move because it will let you know if your soil has deficiencies in nutrients or has certain nutrients in excessive amounts.
The results of your test will come back from the lab in the form of a report. Different labs have different report templates, but most of the reports will have three main elements: the amount of each nutrient, the lab’s opinion whether the amount is low or high and the lab’s fertilization recommendations.
It is your job to interpret the results and figure out what they mean to you.
When a lab tests a soil it measures nutrients that are dissolved in soil water and are readily available to the plants and microorganisms. As you build organic matter and work on improving your living soil, most of the nutrients will migrate into the organic part of the soil. This means that lab report measurements will represent only a fraction of the nutrients that your soil actually contains. This is why your lab fertilizer suggestions will also be much higher than needed. However, if a report identifies a deficiency, it is most likely present in the living soil as well.
A full soil test report will contain information not only about soil properties, but also soil nutrients. Reports from certified laboratories usually show the actual percentages of clay, sand and silt. Organic matter is also reported as a percentage. If you are using the same lab over a number of years, this number will show you how well you are building the health of your soil, underlines Jeffry Hill.