Main Discussion Area
Evaluating the nutrient status of soil is important for maintaining any turfgrass area. Soil testing helps turfgrass managers evaluate soil pH, identify potential phosphorus and potassium needs, and avoid unnecessary fertilizer or amendment applications. A soil test report should be interpreted together with turfgrass species, soil conditions, irrigation, clipping management, and the intended use of the area. Use your soil test as a decision-making tool, not a complete diagnosis of every turfgrass problem.
For established turfgrass with stable soil test values, testing every three to five years may be adequate. However, in particularly troublesome soils or turfgrass areas, or intensively maintained sites (golf course and athletic fields), every one to three years soil testing may be needed.
Taking a Representative Soil Sample
The quality of a soil test depends on the accuracy of the sample. A soil test report is useless if the sample is not representative of the area being tested, so take accurate and consistent samples. For sampling, you will need a soil core sampler, a plastic/non-metal container bucket, pre-labelled bags, and a cooler with ice packs for temporary sample storage. It will be ideal if you can determine in advance the areas you want to sample. For instance, you can plan your sampling using a grid strategy of 1 to 2.5-acre grids, by soil type, management type, or problem area.
For the first two cases, you can use the ARS Soil Sampling Planner Optimizer Tool (SSPOT) to pre-determine the sampling location from your field and retrieve the GPS coordinates that can guide you in the field.
Soil Sampling Questions in Turfgrass Areas
Do I contact the soil laboratory for testing?
Contact the laboratory before sampling to confirm the fees for specific soil tests, sample quantity, preparation, and submission requirements.
How deep to do soil testing?
Use consistent sampling depth. The Simplifying Soil Test Interpretations for Turf Professionals Nebguide (UNL 2265), recommends approximately 6 inches for lawns and athletic fields, and 4 inches for golf course turfgrass areas. The depth should also match the interpretation system used by the commercial laboratory.
What about thatch in soil testing?
Measure thatch thickness separately; soil organic-matter concentration and thatch accumulation are related but are not interchangeable measurements. UNL G2265 recommends recording thatch thickness alongside the soil-test results.
How many samples for soil testing and where?
Take 10 to 15 cores from each relatively uniform management area and combine them into one composited sample in a plastic/non-metal container bucket. Ensure you separate the areas based on turfgrass areas. Examples include:
Different mowing heights/playing surfaces at golf courses (greens, tees, fairways, roughs), in addition to noting the hole location of the sample from the area
Infield vs. outfield in baseball and softball fields
Home lawns soil testing only
Separate soil testing if noted of different soil types in turfgrass areas
Do I keep any plant residue into the soil test?
Remove any plant residue before combining the soil cores and transferring them into the pre-labelled bags.
How to store and transport soil samples?
Store and transport samples in a cooler with ice packs to delay microbial activity until samples can be shipped to the commercial lab. In case samples cannot be ship on the same sampling day to the commercial laboratory, store them in the fridge at 40°F (4°C) and ship them in a styrofoam cooler with ice packs. Any increase in temperature will boost microbial activity, leading to higher decomposition of your soil’s organic matter, and that will overestimate the laboratory results, providing you with misleading readings of your soil status, particularly inorganic nitrogen. Prepare and submit the sample according to laboratory instructions.
Note: Combine the cores to make one composite sample per area. Divide the area if necessary to avoid combining cores from: soils of different texture and color, areas differing sharply in elevation, disturbed and undisturbed soils, and healthy and troublesome areas.
Do I need to keep record of my soil testing?
You should keep records of the sampling depth, date, laboratory, and analytical methods so future results can be compared appropriately. Be consistent with sampling depth, as changing sampling depth, laboratories or analytical methods can substantially change a soil-test result and prevent you from evaluating trends over time.
Choosing Soil Tests and Reading the Results
For routine turfgrass fertility management, focus on soil pH, phosphorous, potassium, and soil organic matter. Additional testing for soluble salts, sodium-related problems, or irrigation-water quality is useful when site history or symptoms indicate a potential problem.
Soil test nutrient concentrations are commonly reported in parts per million (ppm), equivalent to milligrams per kilogram (mg/kg). Fertilizer recommendations are different quantities and are commonly expressed as lbs. of nutrient per 1,000 square feet. Keep soil concentrations separate from application rates.
Next Steps
Nutrients in Soil Testing
Soil Organic Matter (SOM)
Soil organic matter is useful for understanding the root zone, but there is no single ideal organic matter concentration (%) for all turfgrass areas. A sand-based putting green and mineral-soil lawn naturally differ, and organic matter often increases as a new turfgrass stand develops. Interpret SOM results using consistent sampling depth and laboratory methods.
Phosphorus (P)
Phosphorus is essential for turfgrass growth and establishment. However, excess P can contribute to eutrophication of waterbodies (e.g., lakes, streams, and ponds). P deficiencies are rarely observed in established turfgrass in Nebraska, except on soils with very high or very low pH.
Considerations for established turfgrass: use appropriate soil test interpretation to determine whether P is likely needed. Consider soil test trends and clipping removal when evaluating maintenance applications. Do not apply P simply because it is included in a general-purpose fertilizer. No additional P when Mehlich-3 P exceeds 50 ppm (UNL G2265).
Considerations for establishment of turfgrass: first test your soil before seeding or sodding. P-containing starter fertilizer can be useful for P supply, as helping young turfgrass plants to absorb phosphorus from the soil profile is limited. Applying 1.0 lb P2O5/1000 ft2 with a fertilizer high in phosphorus (often sold as starter fertilizer with usually twice as much P2O5 vs N) will improve establishment.
If your soil tests show a deficiency in P, fertilizers that contain P can be used throughout the year, or a fertilizer high in phosphorus can be used early in summer when uptake is most rapid. Table 1 lists P applications for establishing turfgrass and Table 2 lists recommendations for mature turfgrass. Select the fertilizer and rate according to the soil test interpretation and the intended nitrogen application.
Potassium (K)
Potassium supports water regulation and other essential plant functions. However, turfgrass response to K fertilizer is often less predictable from soil testing than response to P. UNL G2265 identifies 40-80 ppm Mehlich-3 K as a management target and recommends no K fertilizer above 80 ppm within that framework.
K deficiencies are rare in turfgrass in Nebraska soils except possibly on coarse-textured, sandy soils. Table 3 lists K ranges on a soil test report and the recommended fertilizer rates. Where K is needed, avoid large applications of high-salt-index fertilizers that could injure turfgrass. Use the product label and a site-specific recommendation to determine application size and timing.
Calcium (Ca) and Magnesium (Mg)
Calcium and magnesium are rarely deficient in Nebraska soils when the pH is above 6.0. Occasionally a report may list Mg as deficient, but this is likely solely due to the testing methodology. Analysis using base cation saturation ratios (BCSR) often indicate false Ca or Mg deficiencies compared to more the more traditional and reliable analysis with sufficiency level of available nutrients (SLAN).
If a soil test report lists Mg as deficient, consider applying magnesium sulfate (Epsom salts) at 1.0/1000 ft2 in 3 gals water/1000 ft2 to a test area. If a response is seen, 2-4 lbs Epsom salts/1000 ft2 can be applied in a granular form and watered in immediately to limit salt burn of turfgrass. Another option is: If calcium or magnesium deficiency is suspected, consider the soil-test method, soil pH, symptoms, tissue analysis where appropriate, and a small treated-versus-untreated comparison before treating the entire site.
Lime should be selected primarily to correct an identified acidity problem. Dolomitic limestone supplies Mg as well as Ca, but additional Mg is not a reason to apply lime where a pH increase is not needed.
Sulfur (S) and Micronutrients
Routine interpretation of S and micronutrient tests is limited by the availability of turfgrass-specific calibration data. Nutrients such as sulfur (S), iron (Fe), manganese (Mn), copper (Cu), boron (B), and molybdenum (Mo) may also be listed on a soil test report. Though S is used in fairly large amounts by plants (macronutrient), these other nutrients are micronutrients and are used in extremely low amounts by grass plants, thus are rarely limiting even in extreme conditions.
High sandy soils with frequent irrigation may need an application of micronutrients on an annual basis. High pH soils and impaired root function can contribute to iron-related chlorosis. Where symptoms occur, evaluate the site and use appropriate tissue analysis or a small fertilizer response trial rather than applying a broad micronutrient mixture automatically.
Toxicity from too much of these elements is more common than deficiencies, so use caution to avoid overuse of micronutrient fertilizers. Do not recommend annual micronutrient applications because the root zone is sandy.
Cation Exchange Capacity (CEC)
Cation Exchange Capacity (CEC) describes the soil's capacity to hold positively charged ions, including calcium, magnesium, potassium, and ammonium. It is influenced by clay content, clay mineralogy, and organic matter. CEC is useful background information, but it is not a complete measure of soil fertility. A higher CEC does not establish that all nutrients are adequately supplied, and a lower CEC does not necessarily mean that turfgrass will perform poorly. Interpret CEC together with the individual nutrient results and site conditions. The CEC of an established turfgrass will not change significantly with time, nor can it be affected significantly by adding fertilizer or chemicals. However, CEC may be increased by adding organic matter to a sandy soil.
Soil pH
A soil pH (also known as active acidity) indicates whether the soil is acidic, alkaline, or neutral. The availability of soil nutrients will vary depending on soil pH (Figure 1). Optimum turfgrass growth occurs between 6.0 and 7.5 pH because most of the elements are easily available within that pH range. Few turfgrass problems in Nebraska are caused by nutrient deficiencies resulting from high pH, but these problems would be most likely on sandy soils.
Soil Buffer pH
Soil buffer pH is a measure of acidity or alkalinity and influences nutrient availability. Managed turfgrass soil pH can range from 5.5 to 8.0 (UNL G2265). It may be listed as lime index or SMP reading, and it indicates the soils capacity to resist a change in pH. The higher the buffer pH, the more resistant the soil is to changes in pH. This number is used by soil testing labs in determining the amount of lime to apply to change the pH. Use the laboratory’s method-specific lime recommendation. Do not compare buffer-pH values directly among different buffer methods or confuse buffer pH with the soil’s measured pH.
Adjusting Soil pH
Acidic Soils: Soil pH below 5.5
If a soil pH is less than 7.0 (acidic), then a lime index is calculated to help make a more accurate lime recommendation. DO NOT APPLY LIME UNLESS IT IS RECOMMENDED. Most Nebraska soils under turfgrass do not need liming.
If lime is recommended, review the following guidelines before making the application.
No more than 100 lbs. of agricultural lime/1000 ft2 should be applied in a single application on higher mowed turfgrass like lawns. On close-mown turfgrass like fairways, application should not exceed 50 lbs. lime/1000 ft2 in a single application.
Ground agricultural limestone or ground agricultural dolomitic limestone are the preferred forms of lime for use on all turfgrass areas.
Lime is very slow-acting, so the pH will not change quickly. Applying lime after an aerification will increase the rate of pH change
Lime does not replace a sound fertilization program.
The limed area should be retested in 2 years to check for a change in the pH.
Hydrated lime (Ca(OH)2) should not be used on turfgrass because it could severely burn grass.
Soil pH from 6.0 to 7.5
It is unnecessary to adjust the pH. This is the pH optimum range for turfgrass growth.
Alkaline Soils: Soil pH above 7.5
Elemental sulfur and acidifying fertilizers can lower pH under suitable conditions. However, carbonate-containing soils can strongly resist acidification, making substantial or lasting pH reduction impractical. A sulfur recommendation should therefore consider soil buffering and carbonate content, not pH alone.
Where high-pH turfgrass is chlorotic, targeted micronutrient treatment may be more practical than attempting to acidify the entire root zone. Diagnose the problem before treatment.
Do not automatically increase N, P, and K rates because soil pH is high. Evaluate individual nutrients and turfgrass performance. High pH may restrict availability of particular nutrients, but it does not establish a uniform increase in fertilizer requirements.
Nitrogen (N)
Nitrogen is central to turfgrass growth and appearance, but a routine soil N measurement is not a reliable stand-alone basis for a season-long fertilizer program. N supply changes through decomposition (i.e., mineralization), plant uptake, irrigation, weather, and losses. Develop the N program using turfgrass species, desired performance, irrigation, growth, length of growing season, soil conditions, and clipping management.
The goal is sufficient growth and recovery without unnecessary stimulation of shoot growth. Returning clippings recycles nutrients. Account for clipping return when developing N, P, and K programs rather than applying the same fertilizer rates to areas where clippings are removed and returned. UNL G2265 treats clipping management as an important modifier of nutrient demand.
Summary
The recommendations on soil test reports have been made from years and years of field data on the expected crop response to a given level of nutrient in the soil. Though most of the work has been done in field crops, more data are being generated from turfgrass areas and recommendations are gradually being revised for turfgrass. However, each specific soil and site can respond differently to nutrients, and thus the ultimate test for soil test recommendations, or any other recommendations for that matter, is the performance of turfgrass on your site.
Soil Testing Labs in Nebraska
STL in NE Pt II
Picture of Fertilizer
Tables Support
Table 1. Recommended total lbs P2O5/1000 sq ft applied between soil tests for bare soil or overseeding. Soil tests should be run every 3 to 5 years after establishment. A corrective one-time application of the amount of phosphorus recommended can be made or a series of applications totaling the amount recommended can be made to gradually build-up the phosphorus level. Modified from the Wisconsin Department of Natural Resources Technical Standard’s “Interim Turfgrass Nutrient Management Guide”
Bray P1 soil test result | Bare soil establishment from seed or overseeding of existing turfgrasss to improve density | Bare soil establishment from sod | |
ppm P | lbs/A P | lbs P2O5/1000 sq ft recommended to be applied between soil tests | |
0-5 | 0-11 | 3 | 3 |
6-10 | 12-21 | 3 | 3 |
11-15 | 22-30 | 3 | 2 |
16-20 | 31-40 | 2 | 2 |
21-30 | 41-60 | 2 | 1 |
31-40 | 61-80 | 1 | 0 |
41-50 | 81-100 | 1 | 0 |
>50 | >100 | 0 | 0 |
Table 2. Recommended total lbs P2O5/1000 sq ft applied between soil tests, given the type of soil test, soil test results, and specific turfgrass area. Soil tests should be run every 3 to 5 years after establishment. A corrective one-time application of the amount of phosphorus recommended can be made or a series of applications totaling the amount recommended can be made to gradually build-up the phosphorus level. Modified from the Wisconsin Department of Natural Resources Technical Standard’s “Interim Turfgrass Nutrient Management Guide”
| Bray P1 Soil Test | Mehlich III Soil Test | ||||||||
Soil test results | Established, lower traffic turfgrass (lawns, parks, golf course roughs) | Established high traffic turfgrass (athletic fields, push-up greens and tees) | Fairways | Sand tees and greens (>50% of rootzone is sand) | Fairways | Sand tees and greens (>50% of rootzone is sand) | Push-up greens and tees | |||
ppm P | lbs/A P | lbs P2O5/1000 sq ft recommended to be applied between soil tests | lbs P2O5/1000 sq ft recommended to be applied between soil tests | |||||||
0-5 | 0-11 | 3 | 5 | 4.5 | 3 | 6 | 3 | 5 | ||
6-10 | 12-21 | 2 | 5 | 4.5 | 3 | 6 | 2 | 3.5 | ||
11-15 | 22-30 | 1 | 3.5 | 3 | 2 | 4 | 1 | 3 | ||
16-20 | 31-40 | 0 | 3.5 | 3 | 2 | 4 | 1 | 3 | ||
21-30 | 41-60 | 0 | 2 | 2 | 1 | 2.5 | 0.5 | 1 | ||
31-40 | 61-80 | 0 | 2 | 2 | 1 | 2.5 | 0 | 0 | ||
41-50 | 81-100 | 0 | 1 | 1 | 0.5 | 1.5 | 0 | 0 | ||
>50 | >100 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ||
Table 3. Recommended total lbs K2O/1000 sq ft applied between soil tests given the specific turfgrass area.
Soil test results | Established, lower traffic turfgrass (lawns, parks, golf course roughs) | Established high traffic turfgrass | |
ppm P | lbs/A K | lbs K2O/1000 sq ft/yr | |
0-25 | 0-50 | 4-5 | 4-5 |
25-50 | 50-100 | 2-3 | 3-4 |
50-75 | 100-150 | 1 | 2 |
75-100 | 150-200 | 0 | 1 |
100+ | 200+ | 0 | 0 |
References
Simplifying Soil Test Interpretations for Turf Professionals. 2016. G2265. Nebraska Extension.
Authors and Contributors
Originally known as Soil Testing for Turf Areas (2012), University of Nebraska-Lincoln Turfgrass Science Program, Pub. Turf 2012g by Zac Reicher.
Edited and Reviewed By:
Amanda Folck, Assistant Extension Educator: Turfgrass Management, Agronomy and Horticulture Department
S. Carolina Córdova, Assistant Professor, Statewide Soil Health Specialist, Agronomy and Horticulture Department
John Fech, Extension Educator, Nebraska Extension
Updated October 28, 2026