Healthy soil is the foundation of productive crops. Whether you grow vegetables, grains, hay, or specialty produce, knowing what is in your soil is one of the most important steps toward better yields and efficient fertilizer use. The MU Extension Soil and Plant Testing Laboratory in Columbia, Missouri provides accurate, research‑based testing to help growers make well‑informed decisions about soil fertility and soil amendments. The goal of this article is to explain how to take a soil sample, how to submit it through your county extension office or local specialist, and how to understand the results once they come back.

Why soil testing matters?

Soil testing helps determine the amount of major nutrients available to plants, the soil's acidity level (pH), and the need for lime or fertilizers. The MU Extension lab analyzes soil for nutrient content, fertility status, and provides unbiased recommendations for economical and environmentally safe nutrient management.
Routine soil testing ensures you're applying only what is needed, prevents wasted fertilizer, and helps protect water quality. Many growers test every 2–3 years to track changes over time. Sample when soils are workable and try to sample at a similar time of year each cycle; avoid sampling immediately after fertilizer, manure, or lime applications.

What other services are available through the MU Soil & Plant Testing Lab?

The lab offers testing for:

• Soil fertility: pH, organic matter, and nutrient content (phosphorus, potassium, calcium, magnesium, cation exchange capacity). Additional tests can be requested for sulfur, electrical conductivity, nitrogen, micronutrients (zinc, iron, copper, manganese) and problematic elements like sodium and heavy metals.
• Plant tissue analysis: nutrient content including nitrogen, phosphorus, potassium, calcium, magnesium, copper, iron, manganese, zinc, boron and molybdenum.
• Additional sample types: water, manure, compost, and greenhouse media analysis for agricultural use.
• The laboratory also provides tailored fertilizer and lime recommendations based on test results.

Samples may be submitted directly to the lab or delivered through your local county extension office, where staff can help you complete forms and prepare your submission.

How to take a good soil sample?

A soil test is only as accurate as the sample you collect. Follow these guidelines to ensure the sample truly represents your field. For detailed sampling guidance, refer to the MU Extension Publication G9070-Soil Sampling Depth and Collection Techniques for Soil Fertility and Soil Health Testing which can be accessed online or requested through your local extension office and Extension Field Specialists.

• A soil coring device such as a probe or auger are preferred. Shovels can work, but make sure to make a hole at the proper depth, then shave a slice of the soil profile from one side of the hole.
• Bucket
• Bags with markers

Where to take a sample?

Divide your field into areas that share similar soil type, crop history, and management. Sample each area separately.

Getting a soil sample

Figure 1 Soil sample boxes provided by the MU Soil and Plant Testing Laboratory, available through your local extension office.

Walk the area in a zig‑zag pattern and collect soil from many points to create a composite sample. Use the bucket to collect at least 10 cores for small plots, and 15–20 cores for larger fields. Collect samples that are 6 inches deep and remove any plant or organic residue from the top.

Mix all the soil cores thoroughly; the composite mixture is the sample you submit. Let the soil air-dry at room temperature (do not oven-dry). The amount of soil is approximately 1 pint, which is the same amount in the sample boxes (Figure 1) available through your local extension office or Field Specialists.

Submitting a sample

The county extension offices provide soil sample boxes, and the local staff can guide you through the process of filling out the submission forms. The county extension offices can also submit the samples to the laboratory. Local extension specialists can also help through this process.

Making sense of the soil test report

County specialists understand local soils and can help interpret your report. They can explain which recommendations are most important for your crop, how to apply amendments, and how frequently to retest your fields. However, soil test reports typically include soil pH and nutrient ratings (e.g., Very Low, Low, Medium, High, Very High) and provide lime/fertilizer recommendations based on crop and yield goals.

For questions you can contact the staff at the MU Soil and Plant Testing Laboratory:

MU Soil and Plant Testing Laboratory
1100 University Ave, Mumford Hall Room 23
Columbia, MO

Telephone: 573-882-623