During the lull of late fall to early spring, when turfgrasses are dormant, many LCOs may experience a decline in revenue-generating opportunities. Some companies take up extra jobs such as snow removal, general landscape clean-up, or tree trimming in order to compensate for a reduced income. Other companies may not have opportunities to generate extra revenue to support existing staff during this annual slow period. 

Starting a yearly soil testing program as part of your business model can aid in the recovery of lost income, provide justification for employee retention during the down season, add value to the customer experience and raise the level of professionalism. In addition, soil testing is considered a best management practice for guiding fertilizer applications and protecting environmental quality. 

What Is The Purpose of Yearly Soil Testing?

First and foremost, soil testing should be viewed as a means to track nutrient applications over time. An annual soil test can reveal how inputs impact turfgrass quality and soil chemical properties, allowing for future adjustments to improve soil fertility to achieve turfgrass quality expectations. As professionals, soil testing and analysis may be commonplace, but these concepts can be confusing to those who have limited experience with soil testing, including customers. Being able to articulate the rationale for including soil testing in your management plan can be highly beneficial and complement your professionalism by showing customers exactly how fertilizer inputs are impacting their turf. In essence, a soil testing program helps LCOs provide answers to common customer questions regarding the value of services in a digestible and educational manner. 

Soil Sampling Equipment

There are a couple of items you will need to obtain in order to operate an efficient soil testing program. The first piece of equipment is a high-quality soil sampling probe. There exist many variations in sampling probes, but a standard probe is 12 inches long with a "T" handle and is made from stainless steel or is chrome plated. If you anticipate a high volume of daily sampling, you may want to consider purchasing a longer probe to minimize the impact on your back. You may also want to invest in a sampling probe with a replaceable tip, as repeated sampling can cause the edges of the tip to become dull or bent. Less force is required to penetrate through the soil if the probe tip is sharp. You will also need a plastic bucket to collect and mix the soil sample. While a 5-gallon bucket is sufficient, a smaller bucket may be a better choice for turfgrass systems. Do not use a metal bucket as it may contain metals that can contaminate your sample and result in an erroneous lab analysis. Remember to always clean your equipment prior to sampling a new location to avoid any cross-contamination.

Sampling Interval

The standard recommendation for soil testing frequency is to test every three years or prior to applying any fertilizer to a new customer's property. In medium to high maintenance turfgrass systems, soil properties can change at a faster pace, and LCOs may see a benefit in shortening the soil testing interval to annually. An annual soil testing program will provide a better sense of trends in soil chemical properties and allow for management decisions to be made before any soil fertility-related issues like nutrient deficiencies or low soil pH arise. 

Consistency In The Key

There are few limitations on when to perform a soil test. In general, soil sampling and testing should be avoided within 6-8 weeks of a previous fertilizer application or when soils are frozen or excessively wet. Waterlogged soils present a significant challenge to the soil testing lab and are difficult to manage in general. While the actual time of year you sample soils is pretty flexible, we do suggest that you collect samples and test soils around the same time every year. Late fall offers an ideal time to complete soil testing activities. The soil is often softer during this time and plant growth and microbial activity have slowed down. Plus, sampling in late fall will ensure you collect the sample before the ground freezes in the winter, which makes sampling impossible. Observing the weather forecasts during late fall will help to determine the appropriate time to begin sampling.

Regardless of when you decide to collect soil samples, collecting a representative soil sample is the most important step in the soil testing process. Proper soil samples ensure that the results of the analysis will be high-quality and meaningful. Since soil nutrient concentrations can vary drastically in space, both across the sampling area and throughout the soil profile, one must collect the right amount of subsamples at the appropriate depth. For established turfgrass systems, we recommend collecting soil to a 4-inch sampling depth. The simplest way to ensure samples are collected to the correct depth is to use a permanent marker and make a line on your soil probe at the desired depth. While this is a relatively simple method to measure sample depth, you will need to periodically re-draw the line as it will fade with repeated sampling events due to friction. A more permanent method is to score a line in the metal probe at the desired depth. Alternatively, one may choose to weld a metal "stop" onto the probe, which is the most accurate, consistent and permanent way to ensure proper sample depth. However, metal fabrication requires specialized welding equipment and might not be a viable option. 

The number of subsamples needed to produce a representative sample is variable and often a subject for debate. However, the goal is to collect enough subsamples from the sampling area to create a representative sample for submission. In general, you can obtain a representative sample with fewer subsamples in small turf areas, while larger turf areas will require more subsamples. A good rule of thumb for most home lawns is to take 8-10 random subsamples from the area that you want to analyze. Next, mix these subsamples thoroughly in a clean plastic bucket to create one homogenized sample for submission. Submit 1 cup of the homogenized sample to the lab for analysis. If the lab does not receive a sufficient amount of soil for analysis, the sample will be rejected, and you will need to retrieve additional soil from the sample site. 

Properties should be split into management zones based on the type of vegetation and fertilization strategy. Each management zone should be sampled separately due to differing soil properties, nutrient requirements and management regimes. For example, turfgrass areas, landscape beds and vegetable gardens should be sampled separately. One should also take note of any area that has a history of poor-performing turf and sample that area separately for troubleshooting. While each property may differ, the standard scheme for sampling lawns is to submit individual samples from the front lawn, back lawn and any other management areas.

There is often debate about whether to remove the verdure or leave it in the subsample. It does not matter if the verdure is removed as the lab will sieve the sample prior to analysis, which effectively removes large pieces of material before testing begins. For soil sampling of turfgrasses, leaving the verdure on is easier, more accurate and less time-consuming, allowing you to sample more properties per day. 

Once you submit the soil sample to a reputable soil testing lab, you should expect to receive the results within a few days to two weeks. If you need assistance with reading and interpreting a soil test report, please contact Cooperative Extension for assistance.

Late Season Liming

While fertilizer applications are prohibited in Delaware from Dec. 7 to Feb. 15, the application of liming materials is permitted during this time. The soil test report will indicate if liming is recommended and if so, how much lime to apply. Coincidently, late fall is a great time to make lime applications. Applying lime well in advance of the onset of active growth should provide sufficient time for the material to react in the soil since it will need to be top-dressed on established turfgrass. Choose a high-quality liming material (fine texture and high calcium carbonate equivalence) as this will reduce the time needed for the lime to react with the soil.

Customer Reports

Since soil test reports contain quite a bit of technical language, you may ask, "How do I relay this information to the customer effectively?". Basic spreadsheet skills are all that is needed to transfer data from the soil test report, allowing you to create simple graphs that can be used to "visually" explain how your management actions have affected the quality of the soil and turf. There are several spreadsheet programs (e.g., Microsoft Excel or Google Sheets) that allow you to create simple data visualizations. If you are not familiar with spreadsheet programs, there may be a small learning curve; however, there are a plethora of online resources available to ease you into these data management programs. I have found YouTube and Microsoft.com to be great resources to explain in detail all of the required functions you will need to create a professional look on your customers' reports. With a little work and determination, you can add more value to your business, separate yourself from the competition and increase customer satisfaction.