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University of Minnesota Extension

Soil testing for lawns and gardens

Submitting a soil test to a lab is the best way to determine the state of your soil. The soil test results will give you recommendations to improve plant performance, saving you time and money.

Why test your soil?

Soil tests provide a snapshot of your soil’s current nutrient levels, and can help you make smart decisions about how much to apply or whether to apply compost, manure or fertilizer.

A soil test can help you:

  • Understand important physical characteristics of your soil including the texture, pH (acidity) and percent of organic matter in your soil.
  • Determine if your soil needs nutrients and choose the right fertilizer.
  • Test for contaminants.
  • Add the right amount of compost or manure.

The three main nutrients that plants require for healthy growth are nitrogen (N), phosphorus (P), and potassium (K). Although they are already present in your soil to some degree, your N-P-K levels may not be optimal for plant growth. Your soil might lack potassium, for example, or you might have more than enough phosphorus. The goal is to make sure your plants are the most productive they can be without applying too many nutrients, which can lead to environmental issues.

When and what to test

Test your soil every three to five years and when you are making a change such as converting a lawn to a garden bed. It's good to test your soil in the spring before planting, or in the fall after you've harvested your garden.

The University of Minnesota Soil Testing Laboratory offers soil test services to the public. The test results will come with recommendations for fertilizing.

The regular soil test is sufficient for most lawns and gardens. The test results will give you the estimated soil texture, pH and percent of organic matter, and levels of phosphorus and potassium.

For an extra fee, you can also test for soluble salts, lead and trace elements such as calcium and magnesium; zinc, iron, copper and manganese; boron and nitrate (see the request sheet for more information).

High soluble salt levels can harm plants and reduce yield, while exposure to lead in soil is a health concern for humans, especially young children and pregnant adults. Trace elements are important for some crops.

Download the request sheet and find instructions from the soil testing lab site.


Measuring the physical properties of soil

In addition to a soil test, you can take some simple measurements to better understand the physical properties of your soil. These measurements are informative, even if you only do them once. But if you do them each year, you can see how your soil is changing over time.

Over the years, hopefully, you will see that your soil structure is improving with the use of soil health practices like cover crops and reduced tillage. Take photos so you can document your results and refer to them in the future.

These methods have been popularized by the Natural Resources Conservation Service.


Applying fertilizer, manure or compost


Authors: Natalie Hoidal and Emily Hansen, Extension educators, Jack Wilcox and Paul McDivitt, Extension communications

Reviewed by: Julie Weisenhorn, Christy Marsden, Chip Small and Carl Rosen

Reviewed in 2023

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