How to test your garden’s soil

soil sample

If you’ve made headway on your gardening to-do list for January, you’ll want to begin thinking ahead to testing your soil.

Ohio State University Extension recommends testing your soil before planting your garden. The purpose of soil testing is to determine the amount of nutrients as well as the pH level of your garden’s soil. The results of a soil test will indicate whether or not you need to add more fertilizer or apply less fertilizer to your soil.

Cornell Cooperative Extension-Tompkins County explains that although there are exceptions, most plants thrive in soil with a pH of 6.8. If soil is too alkaline, sulfur may need to be added; if soil is too acidic, lime may need to be added to balance the soil’s nutrients.

When to test

The best time to test soil is from September to December or from February to April, according to the University of Kentucky Cooperative Extension. However, new sites can be tested whenever the soil is workable. Soil should be tested every two to three years.

Contact a soil testing lab before you take samples. Although Ohio State University Extension offices do not conduct soil tests, they will suggest labs that offer soil testing services. Locate an Ohio county extension office for help finding a test lab.

Michigan State University Extension offers soil testing services. The kit can be ordered online. Once soil samples are received at the lab, MSU Extension will email you within 10 days. Recommendations can be accessed online, regardless of whether or not you sent your soil sample to MSU Extension or not.

Related: Soil testing supplies useful information

How to test

To test your soil, you’ll need a soil probe or auger. If you don’t have either of these tools, a spade, trowel or knife will work.

  1. Remove top debris or residue from the area where you are going to take the sample.
  2. Using the soil probe, auger or other tool, take the sample six to eight inches below the surface.
  3. Take samples from more than one location, according to the instructions in your kit.
  4. Air dry samples, then mix well and crush lumps until they are no bigger than wheat grains.
  5. Take the amount of composite soil specified by your kit and put it in the sample bag provided with the kit.
  6. Follow all instructions for submitting soil samples. Be sure to fill out all paperwork, including the types of plants you grow or will grow. Also, include payment with the paperwork.

You should receive results from your soil test after about two weeks.


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