Know Your Soil: Soil Testing for Lawns and Gardens

What is a soil test?

Soil testing is the process of analyzing the nutrients present in a soil sample to determine the type and amount of fertilizer needed.

Periodic soil testing provides homeowners with the vital information needed to maintain a healthy lawn or garden.

A soil test does not identify or measure insect populations, diseases, drainage issues, pesticides, or other chemical levels.

Why is soil testing important?

Soil testing:

  • Saves money by avoiding over application of costly fertilizer
  • Instructs homeowners how to fertilize for optimal health of lawn or garden
  • Reduces polluted runoff

A basic soil test provides homeowners with the necessary information to begin a fertilization schedule. The results of a soil test will answer four critical questions:

  1. What nutrients does my soil need?
  2. What type of fertilizer should I use?
  3. How much fertilizer should I use?
  4. How often should I fertilize?

Tip: After you receive soil test results, create an annual schedule for fertilization based on the recommendations.

How do I get my soil tested?

Your local County Extension office provides soil testing for a minimal charge.

How do I take a soil sample?

Taking a soil sample is easy. All you need is a trowel and a small container.

  • Use a core device, auger, trowel, spade or other tool to collect core samples from 4-6 inches in depth  Samples should be uniform in diameter.
  • Take 5-10 random core samples from the test area. See illustration.
  • Combine and mix the samples thoroughly in a clean container, removing any stones, grass or roots. Allow to air dry. If the lawn or garden has areas with distinctly different soil conditions, collect samples from each area, keeping each sample separate.
  • Take 1-2 cups of the soil sample mixture to your local county extension center in an airtight, resealable plastic bag.

Avoid taking samples from:

  • Areas which appear abnormal, such as backfill ditches, along fence lines, or under trees and shrubs which may have been given extra fertilizer
  • Spots where grass, vegetable plants or flowers have suddenly died or change color
  • Wet soil

Information to provide with your sample:

  • Previous fertilizer application
  • Uses for the soil (lawn or garden)
  • Any problems that prompted the soil test
  • Abnormal or problem soil conditions
  • Size of your lawn

When should I test my soil?

While you can soil test anytime of year, it’s preferable to test during late summer or in fall before application of fall fertilizer. Avoiding peak times in spring will ensure you receive your results in a timely manner.