Soil tests can save homeowners money and improve growing results by helping accurately determine fertilizer
rates and the need for soil amendments, such as compost. The Lewis and Clark County Extension Office can
assist with sampling advice and tools, mailing samples, and interpreting results.
Collecting a sample
- Remove any mulch or lawn thatch before collecting your soil samples.
- Collect samples from multiple areas around your yard or garden.
- Soil samples are best collected using hand probes or augers (available at the Extension Office) or bulb planters to obtain the same amount of soil from each depth and location.
- Collect soil to a depth of 6 inches.
- Samples may be collected at any time, but it is best to wait at least two months after fertilization to give the fertilizer a chance to dissolve, disperse
and be used by plants. If you take the sample in the fall, keep in mind that you will have more available nitrogen in the spring along with other nutrients than what your analysis indicates.
Sending samples for testing
- The Extension Office uses Midwest Laboratories for soil analysis. Results generally take about 10 days and are sent via email unless requested otherwise.
Reading the results
- Midwest Laboratories has this video available to assist with reading your soil sample results and MSU has this handy guide for Agriculture, but it's very helpful to discuss the findings with your local Extension Agent. They can not only help you interpret the results, but can calculate soil amendments and make recommendations to improve the life of your soil.