A Farmer’s Guide to Collecting Soil Samples

1. Gather your equipment. Clean all tools and buckets to avoid contaminating samples or spreading invasive species or disease. TIP: A shovel can be used to collect soil, though a sampling probe will provide more accurate results. Probes can be borrowed from the Conservation District in your county.

2. To obtain a representative sample of your field or zone, many subsamples are required. To collect subsamples, randomly select 5 points in a W-shape across the field. TIP: Do not choose unusual areas or those with obvious disturbances. Avoid field corners, edges, former fence rows, areas with large rocks, or sections with atypical ponding.

TIP: As you travel from point to point, move carefully to minimize disturbance to plants and soil, and to show proper respect to growers and their fields.

3. The soil depth you should sample will vary depending on your objectives. However, 12 inches is a common depth to learn more about crop nutrient demands. TIP: Use nail polish or an engraver to create a mark 12 inches from the tip of the probe. This will save time in the field, and ensure you push the probe to the same depth at each subsample. TIP: Before sampling, remove surface crop residues, grass, or organic debris. The depth measurement for the sample begins at the top of the soil horizon, immediately following any removed materials.

4. At each of the 5 points, collect 4-5 probes of soil within a 30-foot area. This will result in 20-25 unique subsamples mixed in the same bucket.

TIP: This soil quantity will be enough for nutrient analysis, but check with your lab about the quantity required for other tests.

5. When all 20-25 cores have been taken across each of your 5 points, thoroughly mix the soil in your bucket and break up any clods. Avoid using your hands, especially if you are testing for sensitive biological measurements. Consider wearing gloves or using a shovel instead.

6. When soils are completely homogenized, fill a clean sample bag and label it with the information your lab has requested.

TIP: Keep good records! Note which field each sample comes from, possibly using X-Y coordinates. Keep all sample and management data in one location on your computer, or in a notebook, so you can easily track changes over time.

7. Depending on the measurements you are requesting from the lab, you may need to keep samples cold. In the field, this will require a cooler with ice packs. Try to send cooled samples to the lab on the same day you extracted them. Otherwise, place samples in the refrigerator and send within 2-3 days.

8. When you finish sampling, or in-between fields, wipe down your bucket and tools to avoid cross-contamination or rust.