Soil testing is an important tool for gardeners who apply fertilizer and lime

Regular soil testing is recommended for gardeners who want to maintain a balanced soil, resulting in healthy landscape plants and protecting the environment.

Soil testing is an important diagnostic tool for any gardener who wants to grow quality produce, beautiful flowers and healthy turf. It is recommended that soil is tested every two to three years to maintain proper soil pH and balanced nutrients.

The first step is to obtain 20 soil cores taken randomly from each garden, lawn, fruit planting, flower bed or ornamental planting. The chosen tool to use is a soil probe (Photo 1). The depth of soil cores should be from four to eight inches. Remove any plant material, stone, or other debris. Place cores in a clean container and mix well. Obtain two cups of soil and place in a paper bag. Allow to dry for one week.

A soil probe.
Photo 1. A soil probe is is the ideal tool to
use when obtaining soil cores.

If you decide to send your soil sample to Michigan State University for testing, you will need to visit your local MSU Extension office. Staff will assist you in packaging your soil sample, filling out the paperwork and mailing it out. These services will vary with different offices. The cost for each sample will range from $10 to $20.

Once the sample is mailed out, results will be emailed back to your local MSU Extension office within a couple of weeks. The local MSU Extension educator will make written recommendations specific to your crop. These will include the soil pH, soil type and nutrient requirements. For homeowners, fertilizer and lime recommendations are given in pounds per 1000 square feet. Commercial farmers are given fertilizer and lime recommendations in pounds or tons per acre.

If you need to apply lime and your soil is also low in magnesium, you should use a dolomitic limestone. If you need to apply lime and your soil has adequate magnesium, you can use any limestone. Powder forms of lime will react faster than granular or pellet-sized types. The best time to apply lime is in the fall before snowfall. Lime applications will be effective for up to three years.

Recommendations will also include fertilizer and nutrient application rates specific to your crop and soil levels. These rates are based on annual plant uptake. Both organic and synthetic fertilizer recommendations can be offered. Optimum timing for most nutrient applications is in the early spring, before “green up.” If you decide to use compost or animal manure, have it tested for nutrient content before applying it to your site.

Finally, and most importantly, keep good records. Application of lime and nutrients need to be recorded and correlated with plant production and growth information. This will assist MSU Extension educators in adjusting your application rates to specific crops. Your local MSU Extension office keeps copies of your soil test results for up to seven years in case they are needed. For more information related to soil testing, contact your local MSU Extension office.

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