The following article printed in the November 1, 2018 edition of the Oldham Era.

Soil Testing Saves Money and Plants

As the environment in which almost 50% of a plant lives, quality soil is essential to healthy root development in conjunction with above-ground plant growth. Soil testing helps us understand and manage the nutrient availability and growing environment for plants.

Whether it’s a field crop, garden vegetable, fruit tree, landscape shrub, or lawn turf, each plant has its own soil nutrient requirements that differ based on the plant’s growth characteristics and preferred environment. If the soil is the wrong pH or missing essential nutrients, then the plant will be under stress and unable to defend itself against insects and diseases.

Before purchasing any fertilizer or lime, it is recommended to have your soil tested. The results help identify which nutrients are needed and in what amount. Adding too little or too much fertilizer or lime can result in poor growth or a waste of nutrients that become pollutants in our streams and ponds – not to mention a waste of money!

Soil testing is available throughout Kentucky through the University of Kentucky Cooperative Extension Service and Kentucky Agricultural Experiment Station. The charge for testing and handling varies by county. In Oldham County, a soil test is $10, or county residents can obtain free soil testing vouchers through the Oldham County Soil and Water Conservation District. Contact their office via (502) 222-5123 or oldhamswcd@gmail.com for more information.

Due to renovations at one of Kentucky’s soil testing labs, tests after December 31 will take longer to process. As luck would have it, fall is actually the best time of year for soil testing. Fall testing gives you time to amend your soil for spring gardening. Try to test your soil at least a month before you want to plant so that the soil has time to adjust.

Soil samples are brought to the Extension office where the sample will be registered and sent to the university laboratory for testing. The routine test analyzes soil pH (alkalinity or acidity); extractable phosphorus, potassium, calcium, magnesium, and zinc; and an estimation of the cation exchange capacity (availability of nutrients for plant use). Information for other special tests is available from the Extension agent.

Knowing your soil pH is important because the pH level affects the availability of nutrients as well as the activity of soil microorganisms that affects the nutrient cycling and disease risk. Certain nutrients are more available at certain pH levels. Magnesium, for example, is more readily available at lower pH levels. Most plants grow well in a pH range of 5.5 to 7.5. Before amending soil to adjust pH, it is important to know the preferred pH range of the plants growing in the area.

Collecting a soil sample is easy. Using a small trowel, dig three to five inches into the soil, and transfer a scoop into a ziplock bag, bucket, or whatever clean container you have on hand. Collect soil from multiple places throughout the area to be tested, and mix these collections together to create a sample that will provide a good average of the testing area. Allow the sample to air dry before bringing it to the Extension office. Sample size should be about two cups of soil.

For more information about soil testing and other gardening topics, call the Oldham County Extension office at (502) 222-9453 or visit us online at oldham.ca.uky.edu.

Educational programs of Kentucky Cooperative Extension serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, religion, political belief, sex, sexual orientation, gender identity, gender expression, pregnancy, marital status, genetic information, age, veteran status, or physical or mental disability.

Written by Michael Boice, Oldham County Extension Horticulture Assistant, and Lauren Fernandez, Oldham County Extension Staff Assistant.