To round out our series on soil health we are fortunate enough to have information from Dr. Jason Lessl on soil testing. Jason writes…
Basic Soil Testing
One of the most fundamental, but often overlooked aspects to any successful vegetable garden, flower bed, landscape, or lawn is good, fertile soil. Getting your soil tested by a laboratory is the best and most accurate way to assess your nutrient and pH levels which are vital components of maintaining your soil. The University of Georgia Soil, Plant, and Water lab offers such services (www.aesl.ces.uga.edu). When you send a soil sample to a lab, you will receive a detailed report of soil nutrients levels along with crop-based recommendations on how to fix any potential deficiencies. The steps required to submit a soil sample are simple and can be achieved through a few items commonly found household items. You can start by contacting your local county extension office to acquire soil bags and get information on how to submit your samples. Locate your county office here: http://extension.uga.edu/about/county/index.cfm or call 1-800-ASK-UGA1.
When to soil test?
Soils can be tested any time during the year, although it is typically best to take samples in the Fall/Winter. This is the time of year when most plants are dormant and the soil is most accessible. If pH adjustments are necessary, it is also the best time to apply amendments as it can take several months for them to take effect. Lime (to raise pH) and sulfur (to lower pH) reacts slowly and, if possible, should be mixed with the soil at least two to three months before planting.
How often do I test my soil?
For intensely cultivated soils (i.e. vegetable gardens), an annual soil test is recommended. Otherwise, for lawns and ornamental areas, after medium to high fertility levels are established along with the appropriate pH, sampling should be done every two to three years.
Steps in Soil Sampling
Recommendations about when and how to apply nutrients are only as good as the soil sample submitted for analysis. To obtain a representative soil sample, the following steps are useful:
Map out the entire property. This will help in record keeping and ensure that the soil sample is representative of the entire area. Divide areas such that each soil sample represents one general plant type. For example, separate vegetable gardens, blueberry bushes, ornamentals, fruit trees, lawn, etc. If you have specific problem spots, sample those areas separately.
Use clean sampling tools and containers to avoid contaminating the soil sample. Collect samples with any digging tool you have available (hand trowel, shovel, soil probe, etc.).
Slightly damp soil is the easiest to work with if you can wait for those conditions. Clear the ground surface of grass, thatch, or mulch. Push your tool to a depth of 6 inches (4 inches for lawn areas) into the soil. Push the handle forward in the soil to make an opening then cut a thin slice of soil from the side of the opening that is of uniform thickness, extending from the top of the ground to the depth of the cut. Repeat this process in a zigzag pattern across your defined area, collecting 8-12 samples to mix together. For trees, take soil samples from 6-8 spots around and below the leaf canopy. Take about a pint (~2 cups) of the mixed soil (after removing large rocks, mulch, sticks, and roots) and fill the UGA soil sample bag. Be sure to label the sample clearly on the bag. If the samples are wet, spread the soil out over clean paper and let them air dry. Otherwise, take your samples to your local extension office for submission. Once the lab has received your soil, it will take 2-3 business days to get your report.
Dr. Lessl is a program coordinator for UGA’s Soil, Plant, and Water Lab. He understands the importance of the garden ecosystem as he is studying to become a new honey bee keeper this April! Thanks, Jason, for being part of healthy soil month!
Wishing you all healthy soil!