Discover the Power of Soil Testing: A Practical Guide to Ensure Your Trees Thrive

Testing your soil is a critical step before planting a tree. Testing your soil identifies nutrient deficiencies. Knowing what nutrients your soil lacks helps you choose the right fertilizer to give your tree a healthy start. You also test the soil to check its pH level. Most trees prefer slightly acidic to neutral soil (pH 6-7). If the pH is too high (alkaline) or too low (acidic), it can prevent trees from absorbing nutrients.

A third reason to test your soil is to avoid wasting resources. By understanding your soil’s baseline, you can avoid applying unnecessary fertilizers or amendments. Testing helps you target exactly what your soil needs, avoiding over-application and potential environmental harm from fertilizer runoff. For fruit trees, proper soil nutrients impact the quantity and quality of fruit produced, and a soil test can help you optimize your soil for a bountiful harvest.

Best Time to Test Your Soil
The best time to test your soil is a few weeks before planting. That allows you time to amend the soil if needed, based on the test results. You can test the soil yourself using a home testing kit, which is readily available at garden centers and big box stores. This method will give you a basic analysis of pH and nutrient levels. Convenience is a key benefit of testing the soil yourself. Self-testing also creates a good entry point for those new gardeners to learn more about soil and plant needs.

For a more precise analysis, consider sending your sample to a professional soil testing lab. Local extension offices can often provide recommendations on labs. In Rhode Island, you can test your soil at the University of Rhode Island’s Cooperative Extension, College of the Environmental and Life Sciences. Below is more information on how to do that. (If you’re not from Rhode Island, you can find a state-by-state list of soil testing labs on this website.)

Several private companies offer soil testing services. These labs may offer a wider range of tests or faster turnaround times than university labs.
Here are a couple examples:
• New England Testing Laboratory (https://www.newenglandtesting.com/Privacy.php) in West Warwick, RI.
• New England Specialty Soils Screening Facility (https://www.nesoils.com/) in Lancaster, MA.
Consider factors like the type of test you need, turnaround time, and cost when choosing a testing service.
Soil Testing in Rhode Island

The URI lab offers many free and low-cost informational and diagnostic services to Rhode Island citizens. Its Master Gardeners conduct free soil pH testing for the residents of Rhode Island and surrounding areas from March through October. These tests will help determine soil pH levels and predominant soil texture. It also provides basic information and recommendations for the gradual correction of soil pH and compaction issues.

You have two ways to get your soil tested with this program. You can attend a community event where URI’s Gardening Information and Soil Testing booth will be. See the 2024 schedule here. Or, you can mail-in your sample with a Soil Test Result Report Form. Print the form, complete it, and send it along with your sample to URI Cooperative Extension, 3 East Alumni Ave, Kingston, RI 02881. Please include ‘Attn: Soil Test’ on the envelope.

Here’s a step-by-step breakdown of what’s involved in testing your soil for planting trees. Keep in mind that preparation is critical to getting a good sample for testing:

1. Gather your tools—You’ll need a clean trowel or spade, a bucket, and a permanent marker. Consider wearing gloves for ease of handling soil. Use a stainless steel or chrome-plated soil probe. Brass, bronze, or galvanized tools can contaminate samples with copper and/or zinc.
2. Choose the testing method—Decide whether you’ll use a home test kit (faster but less accurate) or send a sample to a lab (more precise but takes longer).
3. Target planting area—Collect samples from the area where you plan to plant your tree.
4. Sample depth—Aim for 6-12 inches deep, where tree roots will establish. (If you’re testing soil for lawns, go 3 inches down.)
5. Multiple samples—Take 10-15 samples in a zig-zag pattern to get a good representation of the area. Avoid areas with obvious signs of contamination or recent fertilization.
6. Mix it up—In your clean bucket, combine all the collected soil samples and mix them thoroughly. Remove any large rocks or other non-soil particles from the soil.
7. Sample amount—Depending on your chosen testing method, take the recommended amount of the composite sample (usually 1-2 cups) for testing. Label the container with your name, collection date, and intended planting area.
   Additional Tips:
   • A soil probe or auger is the best tool for sampling, especially if the soil is very stony or gravel.
   • If a soil probe or auger is not available, use a garden trowel, shovel, or spade to dig into the desired depth of the soil depth.
   • Cut out a triangular wedge of soil. Then, set it aside (to be replaced after sampling). Slide your blade into the soil again, taking a thin (half-inch) slice from one side of the hole.
   • Store your labeled soil sample in a cool, dry place until testing.
   • Some labs offer online tools to help interpret your soil test results and recommend amendments if you’re using the self-test approach.
   • If you’re submitting your sample to a soil testing lab, you’ll need a soil sample information sheet and a soil sample box. Both are available from the extension office in your county or city.
   By following these steps, you can gain valuable insights into your soil’s condition and ensure your new tree has the best chance of thriving. All the tools mentioned in this article are available online. If you need help taking a soil sample, contact RI Tree. Our experts can guide your through the process.