When to Collect Soil Samples
We recommend conducting a commercial soil test for any new field or site and every 3-4 years for existing sites. A standard soil test will provide information on your soil pH, cation exchange capacity, and the amounts of various plant nutrients—all critical for guiding decisions on planting, fertilizing, and choosing soil amendments or management tactics. You can take a soil sample any time the ground is not frozen. For those who use lime, gypsum, or manure, soil testing at or near the end of the growing season allows time for soil test results to guide your use of these products.
How to Collect and Submit a Soil Sample
The fact sheets below provide general guidelines on how to collect a soil sample for testing, along with laboratories that offer consumer soil testing. We recommend choosing a laboratory first. They may have specific instructions for collecting, preparing, or submitting a sample, but these fact sheets will provide a general idea of how to collect samples.
Choosing a Laboratory for Nutrient and Soil Health Testing
includes a list of commercial and university labs in and near Ohio
Soil Sampling to Develop Nutrient Recommendations (for field crops)
Soil Testing for Ohio Lawns, Landscapes, Fruit Crops, and Vegetable Gardens
Considerations for Choosing a Soil Test Lab
Types of Soil Tests
A standard soil test typically provides pH (and recommendations for adjusting pH), cation exchange ratio, and nutrient levels for phosphorus, potassium, calcium, and magnesium. Other nutrients and properties may or may not be included depending on the laboratory you use.
Soil organic matter increases nutrient reserves for plants and beneficial soil biota, and can improve soil structure and drainage. However, measuring soil organic matter acurately can be a challenge. Be aware that most organic matter is not in a form available for plant use. Ohio State is working to develop affordable tests to better measure active organic matter.
Aggregates are primary grouping of soil particles (sand, silt, and clay) clustered together with root fibers, fungal hyphae, and other organic and mineral substances. The shapes and size of these aggregates defines a soil's drainage properties. This is an emerging test area. You can read more, including several laboratories that conduct aggregate stability tests, in this fact sheet: https://soilhealth.osu.edu/sites/soilhealth/files/imce/WhitePapers/Soil%20Aggregate%20Stability.pdf
Soil Sampling for Contaminant Testing (for homeowners)
Ohio State's Damaged Soil Investigation, Restoration and Treatment laboratory in Columbus provides contaminant testing for lead and other heavy metals. Heavy metal screening is recommended for sites that are urban, industrial, within 10 feet of a current or former structure that was built before 1960, or have an unknown history. Read more: https://dirt.osu.edu/urban-agriculture-outreach/soil-heavy-metal-testing/sampling-instructions
Soluble salts commonly found in soils include calcium, magnesium, sodium, chloride, sulfate, and bicarbonate. High levels can interfere with a plant's ability to take up water. Soluble salts are not typically a concern in Ohio field crops or gardens due to adequate precipitation. However, a soluble salts test may be appropriate if excessive fertilization has been applied repeatedly, if irrigation water comes from a source that may be high in soluble salts (a drainge pond, for instance), and in plastic covered beds or 4-season high tunnels using drip irrigation.
For those using composts, manure, and other organic fertilizers, you can also have these products tested for nutrient content.
Interpreting your Soil Test Results
Many testing laboratories will provide various recommendations resulting from your soil test results. If this is a service you will need, make sure it is offered by the laboratory you use. Local extension educators or crop consultants can also help answer your individual questions based on the crops you are growing and your unique soil characteristics and test results. Basic tips for interpreting a soil test report can be found here: https://ohioline.osu.edu/factsheet/AGF-514