Set lawns up for success by identifying the real needs in the soil.
Jeff Carroll isn’t in the business of selling fertilizer; he’s hoping to mend soils instead. Carroll, owner of Jefferson Sustainable Landscape Management in Woodinville, Wash., wants to create healthy soils without the synthetic amendments.
“We’re going to build your soil so that when you’re seven years into your house and you start to grow and everything is mature now, your soil is going to be better,” he says, noting that in many cases, landscapers will plant non-amended soil and just keep fertilizing.
“I would rather amend your soils, make sure the drainage is better and then put in some organic fertilizer and see how it goes and then deal with issues as they come.”
Flying blind can be costly in wasted fertilizer or failed plantings. Charles Darrah, consulting landscape agronomist and president of CLC LABS in Westerville, Ohio, says that new seedings often fail three times before sticking.
“The reason they catch the third or fourth time is because after that amount of time, they finally have put the right amount of fertilizer down,” he says. “They could be successful doing it right the first time by using the information from a soil test.”
Test and trust.
While there are ways to check the pH of the soil without a full test, Darrah says there’s no other way to find out what levels of phosphorous and potassium are in the soil. He recommends testing new customers within the first year of service and re-testing in the fourth year. “It actually helps the lawn care company demonstrate to the new customer that they’re professional and environmentally responsible,” he says.
CLC LABS in Westerville, Ohio, performs more than 750,000 tests every year on various types of samples. Here are the company's tips for taking a soil sample:
- Sample during the first visit of the season, before you apply any fertilizer. If you've recently applied fertilizer, wait six weeks before taking the sample.
- Remove any turf and thatch before sampling. If you're unable to do that, you can include the turf and thatch with the soil.
- If you include turf and thatch in your initial test, be sure to continue including them in future tests for consistency.
- For turf, use a 3-inch deep sample, but for trees or ornamentals, use a 6-inch sample.
- Soil testing requires at least 10 to 12 cores for a typical 6,000 square foot lawn so take enough cores or the sample will be too small to test.
- Use a zig-zag pattern to get a sample that represents the entire area.
Carroll says that if his company can address soil problems, it can deal with pretty much any other issue. "People will just pump fertilizer and pump fertilizer and pump fertilizer and no one really does soil testing," he says. As he was driving by a 50-foot hedge in the neighborhood, he saw that a middle section was going yellow, while the rest of the plant was green and healthy. “Now is it fertilizer or too much water?” he says. “You could, in essence, do a soil test in that area and see what it is.”
Typically, when doing soil testing, Carroll finds that the soil has way too much nitrogen as a result of over fertilizing. Nitrogen will give you a nice, green lawn, but not long-term plant health, so it’s important to look at pH and other nutrients. Plus, a test can identify what the soil really needs, saving on over-application of fertilizers.
Fewer fertilizer applications mean less expense for Carroll, who says he uses that conversation to build trust with homeowners.
“I do not feel as though we’re losing money on fertilizing because we’re making money on doing the right thing for our client,” he says. “Our client is the one who cares about the environment and it’s about that trust factor. If I’m selling them something that they don’t need and they find out, where’s the trust?”
He’ll let the client know they don’t need as much fertilizer, and then suggest that they use the money for another service like mulching or a building a new patio. “And on the flip side, I can come into this and say ‘How many times are you fertilizing now? If you want to gamble with me, we can cut that down,” he says. “It’s all about the trust of the client.”
Rather than trying to do a soil test in-house, Carroll outsources to a local vendor. He says the cost is about $35 for a soil test, but it can be more cost in the man hours required to collect the sample and drop it off. At CLC Labs, soil testing fees can range from $12.50 for a basic test to $85 for a diagnostic nutrient test that includes pH and nearly all of the common plant nutrients.
When creating a landscape plan, soil testing is crucial, not only for maintenance but irrigation as well.
Steve Hohl, principal at Water Concern in Rancho Santa Margarita, Calif., does an analysis on a new site and zones the areas on the master plan so that the water application can be adjusted.
According to Stephen Smith of Regenesis Management and past president of the American Society of Irrigation Consultants, amended soils are one of the biggest issues in landscapes.
“It’s so common that the top soil gets removed and stock piled and unfortunately it has happened where the stock pile gets sold.
"So the top soil never sees the project again and then you have construction equipment driving around on what used to be subsoil,” he says.
Since the soil is often brought back into good condition with organics and fertilizers, it’s hard to know what the real condition of the soil is, he adds.
“If you haven’t been involved in the spec-ing and the soil amendments and soil prep before irrigation is brought in, then you’re really making a guess at what the soil condition is."