Why test your garden soil?

Soil testing is an important first step toward growing healthy plants in your garden. A soil test can help you:

  • Make informed fertilizer and soil amendment choices.
  • Diagnose and correct plant problems.
  • Learn about a new garden or growing area.
  • Enhance plant growth.

What tests should I get done?

Soil pH 

A pH test will tell you how acidic or basic your soil is. Most plants prefer neutral soils, but some plants grow best in more acidic soils (blueberries, rhododendrons, azaleas, etc.). Soil nutrients are also affected by the soil pH. Learn more: Living on the Land: Managing Soil pH 

Many OSU Extension Master Gardener offices offer basic soil pH testing. Check with your local office.  

Full nutrient analysis soil test

Use a soil testing lab service for nutrient and other soil tests. Soil testing labs have the equipment to run a detailed nutrient analysis (including pH, calcium, phosphorous, potassium, organic matter and more). Find a soil testing lab in Analytical Labs Serving Oregon. 

Tips for using a soil testing lab service: 

  • Visit the company’s website or call for current fees and shipping details. 
  • Most companies offer many different types of tests, and it can be confusing to know what test to order. Ask the company if they have a "garden package" that tests for common soil components important for home gardens. 
  • Request an example report to see what type of information and recommendations they will provide. (Sometimes this is posted on their website already.)
  • Ask if you need to pay extra for an interpretation of the results. (Will the results tell you how much fertilizer is needed? Or if the soil pH needs to be adjusted?) 

Are home test kits worth it? 

Home test kits or devices generally will not provide results as accurate as using a soil testing service. These kits and devices are not recommended for problem solving or understanding your soil nutrient levels in detail. 

How do I collect a soil sample for testing?

To get the most accurate results:

  • Collect your soil sample from the area of the soil where the plant roots will grow. About 6 to 8 inches deep is good for most garden plants.
  • Remove any roots, grass or mulch from the sample for the most accurate test result. 
  • On a budget? Collect soil from different areas of the garden and mix together into one soil sample. This will give you an overall idea of your garden soils.
  • Trying to problem solve or fine-tune? Collect soil from individual garden areas and test each area separately. Make sure to name your samples and make a map so you can match the results with your garden!

Learn more in A Guide to Collecting Soil Samples for Farms and Gardens. 

How do I interpret my soil test results?

You received the soil test results, now what? If you need help understanding the soil test results and deciding what to do next, first reach out to the company that provided the soil test. They may be able to provide a guide to interpret the results. If you’re still not sure, check in with Master Gardener volunteers in your county. They can provide resources and help answer your questions.

Learn more in Soil Test Interpretation Guide.

 

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