The Shawnee County Extension Council provides a lawn and garden soil testing service through Kansas State University. The routine test measures the need for phosphorus, potassium and pH adjustment. A nominal fee is charged for facilities and materials required . Optional tests for nitrogen, organic matter, minor elements, and soluble salts can be requested at additional cost.
Lawn soils should be tested before planting, if possible. If this was not accomplished, a test to establish basic fertility levels should be done. Thereafter, regular maintenance fertilizer applications should keep the fertility up.
Garden soils should be tested every 3-5 years; annual tests aren’t required unless an extreme deficiency is revealed. If organic fertilizer recommendations are desired, please indicate this when you submit your sample for testing. If special plants, such as azaleas or blueberries, are to be grown, this should be indicated also.
The results of a soil test can be no better than the representative sample of soil submitted for testing. Identify what appears to be a uniform area (similar throughout), then take 10 or more columns or slices, at random, from the area to be tested.
Use a spade, probe, auger, or trowel to collect slender cores, columns or slices of soil 5 inches in depth for gardens or flower beds; 3-4 inches deep for lawns. It is important to obtain a representative sample of soil in the root zone rather than from the surface soil. A soil probe can be rented (fully refundable) from the Extension Office to facilitate sampling soil in established lawns.
It is advisable to take at least 10 samples from within the lawn or garden area. Mix these sub samples together to create a composite sample representing a cross-section of the one being tested. Remove any stones, grass, roots, or "thatch".
Take one pint (2 cups) of the mixed soil into a plastic bag to submit for testing. Label it with your name, address, and the site from which the soil was colleted. If you send more than one sample, be sure to label each plainly and bring it to the Shawnee County Extension Office located at 18th and Western, south side of Maner Conference Center, west side of the Expocenter. Your local Extension horticulture agent will interpret the test results and make recommendations on the kind of fertilizer to use.
Do not contaminate the sample with soil from small areas which are abnormal or different, such as backfill ditches, where brush piles have been burned, or under shrubs which have been given extra fertilizer. If a test of soil from these areas is desired, it should constitute a separate composite sample.
If a lawn or garden has two or more distinctly different types of soil, such as fill-soil in one area and native soil in another, make separate samples. Avoid taking samples when the soil is very wet. Samples which are wet should be spread out on a newspaper to dry.
DON'T DRY THE SAMPLE ARTIFICIALLY!!
A report of results and recommendations will be forwarded to you as soon as it is completed. The normal waiting period is about 2 weeks. During peak periods, longer delays may occur when gardeners have failed to plan ahead. To avoid delays, submit samples at any time throughout summer or winter and avoid the rush periods of March to May and August to September.
Soil tests detect shortages of major plant nutrients which affect growth and development of plants. The test doesn’t identify or measure insects, soil borne diseases, pesticide residues, or other contaminants.
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