Man versus nature: Diagnosing turf problems

Heed the clues While circles are common in nature, a perfect circle is more common in man-made items, like misplaced grill covers or kiddie pools. (Photo: LM Staff)

There’s a spot, or a series of spots, in an otherwise healthy yard. No need to apply a fungicide or send a soil sample off to a lab yet. First, play detective and deduce what the problem could be.

“What type of grass is it? Is it seeded or sodded? Young or old? Sunny, shady or mixed?” asks Harold Enger, a semiretired consultant for Spring-Green Lawn Care, a franchise system based in Plainfield, Ill. Enger has a whole slew of questions he asks himself to narrow down the possibilities. “What is the condition of the adjoining lawn? What has the weather been like? Is it a flat lawn or a southern-facing slope? Does the damaged area have a pattern? Circles are common in nature but squares are not. I’ve found four-by-eight sheets of plywood, two-by-fours and stepping stones under grass. It could be as simple as the homeowner setting down a hot kettle grill on the grass.”

A soil test might not be necessary, but a close look at the soil is helpful. A soil pH tester could be employed, but Enger prefers a soil probe and a few pokes in the ground.

“Take some soil probes. Can you even get the dang thing in, or is it just clay?” Enger asks. “Maybe there are a lot of rocks or the moisture level is so bad the dirt just falls out.”

Enger says he used to carry a 3-inch knife with him to cut down into the lawn and remove a V-shaped area that he could show to the homeowner.

“You can’t diagnose turf problems by standing upright,” Enger says. “You’ve got to get down on your hands and knees and put your nose in the lawn.”

Smartphones and soil samples

“I think many soil labs will tell you that about 40 to 50 percent of the soil samples they get, there is no disease present,” says Brian Aynardi, Ph.D., PBI-Gordon’s Northeast research scientist. “Usually it’s cultural — an herbicide issue or maybe even salt.”

Aynardi says the question he’s most frequently asked each spring, especially in the upper Midwest, is why grass around driveways is slow to green up. Could snow mold be the culprit? It’s usually a simple answer: salt damage from winter snow removal.

“If it’s a disease, usually you have an epicenter of infection/death,” Aynardi says. “Typically, it’s not discreet. If there’s a sharp line of damage, next to no damage? That’s not how nature works. As you move away from the center, there should be fewer and fewer lesions. But if it’s 8 feet, 10 feet wide, and it’s a perfect circle? That was probably a kid’s pool in the backyard.”

There’s another tool Nick Strain, business director for Quali-Pro, recommends: the smartphone.

“If you don’t know what it is, take a photo of it and get it to a local company rep,” he says. “If it’s predominantly bluegrass, it’s probably summer patch. If it’s tall fescue, it’s probably brown patch. You can identify these diseases fairly easily from a photo.”

If the troublesome area still can’t be resolved, it’s probably time to ship off a plug to a soil diagnostic lab. But, Aynardi has a few favors to ask, based on experience.

“Find an area that intersects disease and healthy. Leaning toward the healthy area, take a sample, including some soil, a couple inches to keep it together, and use foil to keep it together,” he says. “Do not seal the turf in a plastic bag and ship it ground on a Friday — the lab will smell that package coming before it even arrives. Ship a fresh sample overnight.”