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Test soil to improve gardens, landscapes
By Kaitlyn Byrne
MSU Ag Communications
MISSISSIPPI STATE — For greatest success, gardeners should start by improving the quality of the soil.
Larry Oldham, a soils specialist with the Mississippi State University Extension Service, said soil-related challenges vary across Mississippi.
“We have 250 different soil types, so the problems gardeners will have with soil will differ from location to location,” he said. “Delta soil usually has much higher fertility, but drainage can be difficult. Other parts of the state might not be as fertile, but they may have fewer drainage issues. Each part of the state has its own benefits and challenges.”
Robert Brzuszek, an associate professor in MSU’s Department of Landscape Architecture, said the first step before planting any garden is taking a soil sample.
“Just as one checks under the hood when buying a car, one should always test the soil when beginning any landscape project,” Brzuszek said. “The soil types of a property determine what type of plants can thrive and where they should be located.”
Brzuszek said the county Extension office can supply gardeners with soil sample boxes and instruction sheets on how to take the samples properly. After gathering the sample, return it to the Extension office to undergo testing. The results will list the soil’s pH, structure and fertility.
While gathering soil samples, avoid including mortar mix or concrete chips in the sample. These materials could ruin both the test results and the plants that will one day grow in the soil. Brzuszek advised gardeners to remove these undesirable materials before soil preparation.
Oldham said after receiving the soil sample results, gardeners should incorporate organic matter, such as compost, into the soil.
“Compost is vital for gardens,” Oldham said. “Gardeners need to add this nutrient-rich content to the soil early in the process.”
Brzuszek said adding an organic mulch layer to garden beds is an excellent way to improve soil and plant health, especially for gardeners who did not take soil samples before planting.
“A two-inch layer of pine straw, pine bark, cypress or hardwood mulch around trees and shrubs helps conserve soil moisture, reduce soil temperatures and provide additional nutrients,” he said. “Adding a mulch layer every year helps improve the organic layer of the soil and overall plant health.”
Brzuszek said modern residential construction techniques often leave subsoil spread near the foundation or on the property. These subsoils are often tight clays lacking the structure and texture necessary for good plant growth.
“On poor soil types or in wet areas, it may be helpful to build a good topsoil layer above the ground,” he said. “A successful approach is to match the types of plants that you will use to the types of soils on the property. Native trees and shrubs, such as bald cypress, black gum, swamp red maple and willow oak, are adapted not only to poor soil types, but also wet soil conditions.”
Brzuszek said problems can arise in home landscapes if soil drainage is poor. Because plants with damaged root systems cannot take up water very well, one of the first symptoms of damage from soggy soils is wilting.
“Affected trees and shrubs also show symptoms of nitrogen deficiency, one of which is yellowing of the leaves,” he said. “Cessation of growth, twig dieback and leaf drop are also common symptoms.”
Oldham said another vital tool for successful gardens is cover crops.
“Planting some sort of cover crop will help keep the soil from washing away, since you don’t want bare ground,” he said. “Soil is a valuable commodity, and we want to hold on to it.”
For more information on soil testing, download Information Sheet 1294, Soil Testing for the Homeowner.