Ohio State expert warns about effect of rock salt on plants

SPRINGFIELD, Ohio—Rock salt and other de-icing agents can be especially useful in tackling the ice and snow during cold, long winters. However, according to a horticulture expert at The Ohio State University, if misused, these chemicals can cause damage to surrounding plants.

Consumers have used de-icing agents for years to remove snow and ice from driveways, sidewalks, and porches. The rock salt lowers the freezing point of the ice by creating a solution of water and salt.

However, this salt has other damaging effects: pitting of concrete sidewalks and driveways, as well as harming plants, shrubs, and grass in surrounding areas, said Pam Bennett, an associate professor in the College of Food, Agricultural, and Environmental Sciences.

“High salt content changes the chemistry of the soil so that plants can’t absorb water and the roots dry out,” said Bennett, who is also the state Master Gardener Volunteer program director for Ohio State University Extension, the college’s outreach arm.

The problem is worse in especially snowy and icy areas or seasons, simply because there is more rock salt being used.

“If you are using salt constantly, you may notice more damage,” Bennett said.  

Plants affected can range from turfgrass to white pines. Often however, plants on the roadsides and sidewalks see the most damage, because they are exposed to higher amounts of the salt.

“It is similar to applying too much fertilizer,” she said. “If you spill a large amount of it in one spot, you will see turf burn from the high amounts of salt.”

Luckily, there are ways to de-ice your driveway without damaging the surrounding plants.

“The best thing you can do is switch to a nonsodium de-icing agent such as calcium chloride or calcium magnesium acetate,” Bennett said.

You can also put in a protective barrier, such as a snow fence or a set of burlap sacks around the plants.

Finally, make sure you spread whichever de-icer you use properly.

“Most people just take a handful and toss it around,” Bennet said. “Make sure you are applying it according to label directions so it doesn’t bunch up in piles that cause damage.”