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.
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:
Tip: After you receive soil test results, create an annual schedule for fertilization based on the recommendations.
- What nutrients does my soil need?
- What type of fertilizer should I use?
- How much fertilizer should I use?
- How often should I fertilize?
How do I get my soil tested?
Your local County Extension office provides soil testing for a minimal charge.
There are also online businesses which sell soil testing kits such as EarthCo, Inc.
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 six inches in depth (3 in. on established lawns). Samples
should be uniform in diameter. - Take 10 or more random core samples from the test area. See illustration.
- Combine and crumble, then blend the samples thoroughly in a clean container, removing any stones, grass or roots. If the lawn has areas with distinctly different soil conditions, collect samples from each area.
- Take one cup of the soil sample mixture to your local county extension center in a small, clean, covered container.
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
Soil tests monitor plant nutrient levels and pH levels which may adversely affect plant growth.
A soil test does not identify or measure insect populations, diseases, drainage issues, pesticides, or other chemical levels.
Information to provide with your sample:
- Previous fertilizer application
- Uses for the soil
- Any problems that prompted the soil test
- Abnormal or problem soil conditions
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.