How to protect your grass after heavy rainfall, according to a golf-course superintendent

flooded yard

Resting water can heat up and scald your grass.

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When it rains it pours. And when it pours, flooding can happen, which is no good for grass.

A year ago this August, the tail end of a tropical storm swept through North Carolina, causing devastation that made all things golf-related seem inconsequential. Still, courses were hit hard.

Jeremy Boone, a long-time member of the Golf Course Superintendents Association of America, is the superintendent at Springdale Resort, in the mountains near Asheville, where some 20 inches of rain fell in a matter of hours, flooding the grounds and closing the course for two months.

We asked Boone about the ill-effects on turf when there is water, water everywhere, and what courses — and homeowners — can do to minimize the damage.

What happens under water?

Like the rest of us, grass needs to breathe.

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“Imagine trying to drink a 20-ounce bottle of Coke while holding your nose,” Boone says. That’s what it’s like for turf underwater. The soil beneath it is composed of solids and porous spaces, which in turn are occupied by water and air.

Those two elements, Boone says, need to be in balance for the plant to “operate correctly.” When the root zone floods, the grass can drown. Over time, saturated roots can also rot or get devoured by fungus.

The perils of puddling

Puddles aren’t just bad for playability. They’re especially problematic when the sun shines brightly and temperatures rise, as is often the case in the wake of an afternoon thundershower.

In those conditions, Boone says, “the puddle heats up and scalds the grass. The turf, he notes, becomes “like an ant under a magnifying glass.”

How long can flooded turf survive?

For days, Boone says, though there’s no set rule. The timeframe depends on a range of factors, including temperature, cloud cover and the amount of contaminants in the water.

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The safest bet is to remove as much water as quickly as you can. If you’re Augusta National, simply switch on your SubAir system. Otherwise, Boone says, a squeegee should do the trick. In the most heavily flooded areas, you can even scoop out the water with a snow shovel.

Keys to recovery

Flood is over, land is dry. What to do next? First things first, assess the damage. If the grass is still green, it should be okay, Boone says. But, he adds, you should still carry out the turf-care version of CPR and “aerify, aerify, aerify,” which promotes the flow of air and water through the root zone.

Depending on the time of year, applying fertilizer can also help. Rotting grass stinks, Boone says, so if you detect an unpleasant moldy funk, it might be too late. The same is true if the turf turns straw-colored. It’s probably time to reseed.

Impurity problems

Excess water is not the only problem. There are also the contaminants that come with it, such as silt, rocks, limbs and (worst of all, Boone says) petroleum products.

“Rocks and limbs can be picked up,” he says. “And silt can be hosed off.”

But when gasoline and oil seep into the ground, they tend to stick around. Though bacteria in the soil can help degrade those products, especially with the help of fertilizer, that process takes time, which is bad news for your turf, because, Boone says, “you need good soil to grow good grass.”

Josh Sens Editor

A golf, food and travel writer, Josh Sens has been a GOLF Magazine contributor since 2004 and now contributes across all of GOLF’s platforms. His work has been anthologized in The Best American Sportswriting. He is also the co-author, with Sammy Hagar, of Are We Having Any Fun Yet: the Cooking and Partying Handbook.