Growing Green: Soil Health and Fertility
I have had many calls asking whether garden soil tests should be submitted in the fall. The answer is YES! Now is the perfect time to submit soil tests, and amend your gardens per the results based recommendations. A little time and preparation now will save time in the spring when all you wish to do is plant, PLANT, PLANT!
The first step in submitting a soil test is to take a representative sample from your yard and garden. Proper collection is crucial to accurate test results. If the area is fairly level and the soil appears to be uniform, collect a composite (mixed) sample. If your lawn or garden has large areas which differ in fertility, take one sample from each area. For example, you may want to sample the front lawn and the back lawn separately. Do not include soil from the lawn area and a garden in the same composite sample. Sample separately or avoid trouble spots or small areas such as borders, low spots, near trees or buildings, etc.
Using a garden trowel, small spade or other good digging tool, scrape away or discard any surface mat of grass or litter. Sample the lawn or garden area to the sampling depth of about 6". Send the soil sample into the testing lab. It takes about three weeks to receive your test results by mail.
The University of Minnesota Soil Test Report is focused on describing the fertility status of your soil and providing information that will help improve the mineral nutrition of your plants. A basic test ($15.00) will indicate your soil texture, the % of organic material found in your soil, phosphorous and potassium levels, and the acidity/alkalinity of your soil. From these numbers, the soil test will recommend rates of application of Nitrogen, Phosphorous and Potassium to create and maintain optimum soil health and fertility. If you want more in depth information regarding lead, excessive salts, and several assorted micronutrients, these tests are available at an additional cost.
Testing your soil before planting, especially when establishing a new garden, will give you the information you need to create a successful lawn/garden space. For more information on understanding soil tests, consider visiting: http://www.lovesgardens.com/Attachments/SoilAnalysisBooklet1.pdf . For soil test forms visit http://soiltest.cfans.umn.edu/test.htm, or call Douglas County Extension at 320-762-3890.
Until next time, happy gardening!
Robin Trott is a Horticulture Educator with University of Minnesota Extension.