UNL Extension – helping you turn knowledge into "know how"
Soil Testing & Amendments
submitted by Sarah Browning, UNL Extension Educator
If you're concerned about the soil quality in your landscape, whether it's your turfgrass, ornamentals or vegetable garden, a soil test can give you basic information to help you start improving it. Soil testing isn't very expensive or difficult to do and can be done anytime the soil is not frozen.
Start by locating a soil testing laboratory near you. Several labs are available in Nebraska including: AgSource in Lincoln, http://agsource.crinet.com , (402) 476-0300; and Midwest Laboratories in Omaha, http://www.midwestlabs.com/, (402) 334-7770. On their websites, soil testing can be found under "Agronomy & Feed" at AgSource and under "Agriculture" at Midwest Labs. Contact the lab or visit their website to request a soil sample test kit and submittal form. Testing costs approximately $15.00 per sample.
Decide how many soil samples are necessary for your landscape. One sample is usually sufficient for most landscapes unless there are obvious soil differences, then each unique area should be sampled separately. It can also be beneficial to sample areas separately based on their usage, so that samples are submitted individually for turf, ornamentals and vegetable gardens.
Create your soil sample by taking 10-15 soil cores from random locations within the sampling area. If you don't have a soil probe, you can use a shovel to collect samples at a 5-6 inch depth. Remove any vegetation or thatch from the soil cores and combine them all into one container. This aggregate collection of soil is your sample. Place 1 to 2 cups of well-mixed soil in a plastic bag or the sample container provided by the lab.
Choose a test that will give results for residual nitrogen, phosphorus, potassium, organic matter, cation exchange capacity (CEC) and soil pH. Your soil test results will usually arrive in about two weeks, along with recommendations for soil amendments in your landscape based on the plant types you indicated on the submittal form. If you have questions about reading the soil test results or potential soil amendments for your garden, call your local university extension office. To find your local office, visit office/locate.shtml
Tips for Soil Amending
- Soil amending can be done in spring, but don't work the soil when it is wet to avoid soil compaction and the creation of hard clods. Fall is an excellent time of year for soil amending, because it allows time for the soil structure or chemistry to change before a new growing season begins.
- Organic matter breaks down over time, so raising and maintaining your soil's organic matter content will require repeated amendment.
- Keep in mind that Nebraska's clay soils have a high buffering capacity or the ability to revert to the original pH level after amendment with sulfur. Maintaining a lower soil pH will require repeated amendment.
Another great resource is the publication "Fertilizers for Vegetables in Home Gardens", which contains detailed information on adjusting soil pH, amending with organic matter and adding fertilizer.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office