Living Columns & Blogs

Start at ground level with soil testing

This photo shows a yellowing young leaf, though its veins remain green, indicating that this plant is hungry for iron. Plants do tell us when they are hungry — with poor or distorted growth, and with leaf discolorations. Test your soil every few years.
This photo shows a yellowing young leaf, though its veins remain green, indicating that this plant is hungry for iron. Plants do tell us when they are hungry — with poor or distorted growth, and with leaf discolorations. Test your soil every few years. AP

My favorite time of year is here! The leaves are turning, the air is crisp (some days anyway), and many of the landscape problems have begun to slow. This is a good time of year to take a breath and make some calculated decisions about the future of your landscape. Soil testing is one of the decisions I hope you will make. This one simple test will give you some insight on your soil’s potential and limitations.

Plants need essential nutrients to flourish, much like people. If these are not supplied in adequate amounts, problems will inevitably occur. Plant nutrients are divided into two groups. The macronutrients (nitrogen, potassium, calcium, magnesium, phosphorus, and sulfur) are required in larger quantities, while the micronutrients (chlorine, iron, boron, manganese, zinc, copper, molybdenum, and nickel) are required in smaller ‘doses.’ A soil test report will contain fertilizer recommendations, as well as a pH analysis.

The soil pH matters more than you might imagine. While a neutral pH is around 7.0, many plants prefer a range of 6.2 and 7.2. There are some plants, like blueberries and azaleas that prefer a lower, more acidic, pH. The correct pH allows plant roots to efficiently absorb nutrients when fertilizer is applied. You can add a truckload of fertilizer – but, if your pH level is not in the correct range, it will be useless to the plants.

In Georgia, our soils tend to be more acidic. The addition of limestone raises the pH level to an appropriate range prior to planting. Lime takes several months to become soluble and move down into the soil profile. Dolomitic lime, which contains both calcium and magnesium, is recommended for homeowners. Although it is initially slow to change the pH level of the soil, it will maintain the pH level longer.

Soil tests also give site specific information for fertilizers. The report will outline what type of fertilizer is needed, the amount necessary, and the recommended timing of application.

Routine soil testing is easy and affordable. While soil testing can be done throughout the year, autumn is the recommended time. This will allow the amendments, particularly lime, to work down into the soil profile before spring when new growth begins.

When collecting a sample, gather soil from eight to 10 random areas around your yard. Dig down 4-8 inches deep where roots grow. Mix a scoop-full from each of the different areas together in a plastic bucket. From this mixture, take one cup of soil to your local extension office. Fees vary per county but typically fall between $6 and $8.

What a great tool for landscapers and gardeners! For more information on soil testing procedures, visit http://extension.uga.edu/publications/detail.html?number=C896

or contact your local extension office.

UPCOMING EVENTS — 2018 Master Gardener Extension Volunteer program: Classes will be held each Thursday from Feb. 1, 2018 through April 26, 2018. Prior plant experience is not necessary; a heart for community service is. Bibb County residents should contact Kathy at 478-751-6338 or kensley@uga.edu to receive application materials. Class fee is $225 (scholarships may be available). Applications are due Nov. 30.

Karol Kelly is the County Extension Coordinator and Agriculture and Natural Resources Agent.

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