Gary Y. Gao, Ohio State University Extension, Clermont County; Maurice E. Watson, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, Ohio; Joseph F. Boggs, Ohio State University Extension, Hamilton County and Southwest District; and James A. Chatfield, Ohio State University Extension, Northeast District and Department of Horticulture and Crop Science.
"Don't guess — soil test!" has long been a recommendation for farmers and growers, and it remains true for modern horticulture, from nursery and greenhouse growers to landscapers and arborists. A soil test is an excellent way to measure soil fertility. It is also a very inexpensive way to help maintain good plant health and maximum crop productivity.
The standard soil test provides the status of phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), pH, cation exchange capacity (CEC), lime requirement index, and base saturation. Additional tests are also available for iron (Fe), zinc (Zn), manganese (Mn), soluble salts, and nitrates.
The Research and Extension Analytical Laboratory (REAL Lab) run by The Ohio State University was closed in December 1998. However, there are several commercial labs that offer the same or similar tests as were used by the REAL Lab. There are also soil and tissue testing labs administered by land-grant universities such as Michigan State University, Penn State University, and the University of Kentucky. For a fee, most of these labs will test soil, soilless media, plant tissue, compost, and water. The amount of fertilizers, timing of fertilization, and amount of soil pH modifying agents, such as lime, will be given according to the type of crop, based on soil test results.