Turf & Rec

Features Agronomy
Soil sampling made easy

October 9, 2012  By  Mike Jiggens

Soil testing by lawn care professionals on their customers’ lawns helps
removes the guesswork from prescribed fertility programs and ensures
their customers are spending their dollars more wisely.

That was the take-home message by Dan Clarke of Activation Laboratories to an audience of lawn care professionals at the second annual Nutrite Customer Appreciation Day in August at Guelph’s Springfield Golf Club.

“One of the simplest tools to understand what you do with your fertility program is to start with basic soil sampling,” he said.

Sampling the soil and having it laboratory tested provides a “nutritional map” of the soil and allows the lawn care professional to plan forward for the soil’s nutritional needs. A good soil testing program will identify deficiencies in the soil up front and will allow for them to be corrected before the customer is aware of any problems or the onset of a stress situation, Clarke said.


At the end of the day, the lawn care professional is judged according to how green the grass is, he said, and achieving that goal most effectively is important.

Clarke recommended testing be done in the fall which gives the professional plenty of time to put a program together for the customer well in advance of the spring season.


“If you can do all this planning in the winter time and put these programs together for your customers, it really breaks up your workload, you’re ready for spring, and then you’ve got a good, satisfied customer.”

Soil testing also demonstrates due diligence by using best management practices and being environmentally conscious, Clarke said.

“We don’t want to see the same thing happen in the plant nutrition industry as what we’ve seen to plant protection. If we’re not careful, we could see the same things happening from a plant nutrient perspective. If we put together a good program where we’re demonstrating due diligence, we should be feeding that plant what it needs based on what the soil test is telling us.”

This allows professionals to show those who believe the industry is polluting the planet that lawn care practitioners are being environmentally responsible and are putting together good programs to meet the needs of what they are trying to grow.

Clarke suggested soil testing should be done every two to three years, noting the nutrient levels in the soil don’t change that quickly.

“What you’re really trying to do is create a history of what is happening in that soil for your turf production.”

A soil test will provide a “snapshot” of what is happening in the soil at the present time, yet it’s important to repeat that testing every few years to provide a full history of how things are changing.

The lawn care professional’s goal is to look at a customer’s soil fertility and use the report to build a “recipe” for the customer and develop an appropriate fertilizer program. The test lists not only the major nutrients in the soil, but all micronutrients as well as their ratios.

“Not only do you need to know the level of the nutrient in the soil, but at what ratio are those nutrients compared to others.”

Clarke said it is known that different nutrients are related to each other and that some will hinder the uptake of a different nutrient while others enhance their uptake.

In order for the tested sample to provide all information necessary, what is sent to the lab must be carefully removed from the ground and packaged. Clarke said a stainless steel or nickel-plated probe or spade should be used to extract the sample, warning that a galvanized tool should be avoided at all costs. A galvanized instrument can allow flakes to mix in with the sample, causing zinc levels to skyrocket.

He added a clean plastic bucket should be used to collect the samples and not a vessel that has been lying around for some time and which may have been previously filled with a chemical compound which could risk contamination of the sample.

When retrieving a sample from the ground, remove any thatch or plant material from the sample before sending it to the lab, Clarke said. As a rule, he added, don’t probe any deeper than six inches for the sample. A depth of four to six inches will produce an ideal sample for home lawns, sports fields or industrial areas.

“Depending on the area you’re sampling, often you get into these industrial or residential lawns and you’re hitting rocks and pebbles and stuff and may have a hard time getting that probe down three inches.”

Remove all rocks and foreign debris from the collected samples, Clarke said, and avoid getting any of the subsoil into the sample. Most of the turf is growing within the top four inches.

“Four inches is a good rule of thumb as to what to sample.”

When sampling an area, adopting a zigzag or “M” or “W” pattern on the lawn will provide good representation of the area. A minimum of 15 cores should be sampled from a lawn to provide that desired “snapshot,” he said.

In the lab, the collected sample is dried and ground, leaving a teaspoon-sized sample to measure from one that was originally cup-sized. This is why it is important to collect a minimum of 15 cores to ensure good representation of the area being sampled, Clarke said.

“Treat each area as a management zone.”

For a typical home lawn, the front yard is usually different than the back yard for a number of reasons, he said.
Often, excess building materials are dumped in the back yard and covered with a half-inch of topsoil and native sod. The back yard, therefore, should be sampled separately from the front.

“Make sure you clearly indicate where those samples were taken.”

Sampling should also differentiate lush areas from dry areas on the same property to that those management zones can be managed separately, Clarke said.

“When you collect those cores, put them in the plastic bucket and make sure you mix it really, really well.”

Clarke showed his audience the type of soil sample bag recommended for use. On it are blank spaces for the necessary information to be entered out and a fill line indicating the requested volume of soil. He warned his audience not to cheat, but to fill the bag to the line. Simply tossing in a few core chunks is inadequate and will likely result in an improper analysis.

“I can’t stress enough…make sure there’s enough sample in the bag.”

Each sample should be clearly marked with the information entered on the bag’s outside before it is filled with the collected sample. The information on the bag should also match that of the submission form to be sent to the lab.
Submission forms can be obtained from Nutrite. Lab results will be returned first to Nutrite within three business days where agronomist Sean Jordan will review the results technically and then meet with the lawn care professional to help develop a customer program.

When the samples are obtained by the lab, they are dried slowly—usually overnight. If drying is done too quickly, some of the nutrients are at risk of being burned off. The analysis is done the day after drying is complete, and then another day is usually earmarked for the lab’s chemist to look over the results and verify everything is correct before the information is sent to Nutrite.

Other speakers

Also speaking at Customer Appreciation Day were Rich Hawkes of Sustane Natural Fertilizer of America and Andy Drohen of Agrium Advanced Technologies.

Hawkes spoke of the benefits of using turkey litter as an organic fertilizer and soil builder. With the highest nutrient rate among all manures, turkey litter replenishes the soil with essential nutrients and a rich supply of humus which is dense in nutrients and contains essential micro-organisms with low burn potential.

Drohen, who is responsible for all slow and controlled-released nitrogen products for Agrium in the northeastern United States and Canada, spoke of recent advances in controlled-release fertilizers, noting changes in coating technology to allow for gradual, more consistent release.

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