Each state in the upper Midwest applies between 100,000 to 300,000 tons of de-icing salt to their roadways every winter. As it dissolves it is absorbed by the roots of nearby plants where it reduces nutrient uptake of potassium, calcium, and magnesium. Additionally, it causes soil aggregates to break down, resulting in poor aeration and drainage.
Some species including, Autumn Joy Sedum, lily turf, dianthus, columbine, lavender, and the too commonly grown “Stella de Oro” daylily, are halophytic or salt-tolerant where others such as Eastern Redbud, Kentucky bluegrass, forsythia, and hemlocks are sensitive to salt.
Sodium chloride combined with sand is commonly used to de-ice roads and sidewalks. When sprayed onto plants by automobiles and snow plows, it enters plant cells or the spaces between cells and causes the buds and small twigs of salt-intolerant species to lose their cold hardiness.
Although we cannot control the use of sodium chloride spread on our city’s streets, we can do something to minimize sale damage to our lawns. Avoid using it! Instead, spread calcium chloride on your sidewalks and driveways. It melts ice at temperatures to -25F degrees, gives heat off as it melts, and if used as recommended will not harm vegetation.
A better alternative would be using environmentally friendly calcium magnesium acetate (CMA), a product obtained by using dolomitic lime and acetic acid. Although it is 20 times more expensive than calcium chloride, it will work at 0 degrees, provides calcium and magnesium to plants, has a low toxicity, requires few applications, last longer, and is biodegradable.
In ancient Spain and Portugal, salt was poured onto land owned by a convicted traitor, making it sterile.
Ed Myers (EMyers3670@aol.com) is a past president of both the Irvington Garden Club and the Garfield Park Master Gardener Association. Additionally, he is the Steward of both the Benton House and Kile Oak Habitat Gardens.