Do you routinely fertilize your lawn or garden? How do you know you are giving your plants the right kind or amount of fertilizer? You can save money, improve the health of your plants and protect the environment from fertilizer run-off by doing a soil test that will tell you exactly what your landscape needs.
The test results will only be as good as the sample you take. The best results will be from a test that is a mix of soil from at least five different spots. But don’t combine soil from your lawn, your vegetable garden and your flower beds into one sample. The plants that grow in each of these areas have very different requirements and the soil is likely very different in each of these spots because of how you’ve treated the soil in the past. Make a composite sample of five spots from your vegetable garden and separate composite samples from your flower beds and lawn. You might even take separate samples from your front yard and back yard if the quality of the turf is very different.
To take a sample, dig down and take soil from about 4 inches in an established lawn and 5-7 inches in a garden or new lawn. You can use a shovel, trowel or soil auger to get the soil. From the five separate spots collect a total of one to two cups of soil.
The Winnebago County Extension office has wax-lined soil sample bags (or you can use a clean, strong plastic bag) and Soil Information Sheets that you fill out and return with your soil sample. You need to fill out one sheet for each sample. The more information you provide, the better the recommendation you will receive. Return the soil sample to the Extension office or send it directly to the UW Soil and Plant Analysis Laboratory, 5711 Mineral Point Road, Madison, WI 53705. The phone number is 608-262-4364. You can also print the Soil Information Sheet from the internet at http://uwlab.soils.wisc.edu.
Each soil sample tested costs $15. The test will tell you your soil pH, lime requirements, organic matter percentages, phosphorus needs and potassium needs. There are additional fees for any special soil tests. Some of the special tests are for lead, zinc, boron, calcium and magnesium. Excesses or deficits of any of these in the soil can cause problems with plants. The fees for those tests can also be found at the website mentioned above.
Soil samples can be taken any time the ground isn’t frozen, but early spring and late fall are best. Take the sample when the soil is relatively dry and don’t sample right after applying fertilizer as that will be an inaccurate representation. Experts recommend that soil samples be taken every three years.
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