Plant growth and development are influenced by environmental factors. One major environmental factor that controls growth in the garden is soil. Soil holds nutrients, and contaminants. Nutrient levels can be too low for plant growth, adequate or exceed plant needs. Nutrients can be added to the home garden at levels that can rapidly shift the balance from low or adequate to excessive. In this way soil is more controllable than many other environmental factors that influence plant growth in the garden.

This chemical environment is not easily measured by homeowners. Testing a sample can provide a great deal of information. Soil testing in a laboratory provides a great deal of accuracy and quality control not available through other methods of evaluating soil nutrient levels. Soil samples tested in Wisconsin typically include results for soil pH, organic matter, phosphorus and potassium. These tests provide information that can be used to guide the improvement of garden soil by addition of amendments and fertilizers. Additional information on sample collection and testing is available at: http://learningstore.uwex.edu/assets/pdfs/A2166.pdf.

In addition to the improvement of soil, soil testing can help you evaluate soil contamination. Lead is a common soil contaminant of soils in urban environments. Lead contamination is most common near painted buildings built before 1978 and where the soil has been exposed to leaded gasoline exhaust. Testing likely sites for lead can help evaluate risks of lead contamination in the garden. More information on lead in the garden is available at: https://learningstore.uwex.edu/Assets/pdfs/A4089.pdf and https://learningstore.uwex.edu/Assets/pdfs/A4088.pdf.