Easy on the salt

effectiveness at temperatures above 10 degrees Fahrenheit.

Still, calcium chloride does put chloride ion, which plants don’t like, into the soil, and it is more expensive and more corrosive to vehicles than sodium chloride.

Chemical (synthetic) fertilizers are all salts, so someone hit upon the idea of using them for de-icing. But besides being more expensive than either sodium chloride or calcium chloride, fertilizers such as potassium chloride or ammonium nitrate are most effective only at temperatures above about 20 degrees Fahrenheit.

Furthermore, ammonium nitrate is corrosive to concrete, and both compounds have a high “salt index,” so are apt to burn plants anyway in the amounts used for de-icing. Potassium chloride, of course, also can put excess chloride ion in the soil.

A popular, relatively new salt used for de-icing is calcium magnesium acetate, better known as CMA. Produced when limestone and vinegar are brought together, CMA eventually decomposes and is not damaging to plants or soils. It also sticks to the pavement better than salt and does not cause corrosion.

CMA does have shortcomings. It’s most effective above 15 degree Fahrenheit (about the same as rock salt). It’s slow to begin working. And it’s a lot more expensive than salt. CMA is better at preventing icing rather than getting rid of ice, so is best applied before ice forms.

Yet another de-icing method is to spread something other than salt on the ice; gritty materials such as sawdust, unused kitty litter, wood ash or sand are effective. Still, nothing’s perfect. These materials track indoors unless you take or shake off your shoes at your front door.

ADOPT A HOLISTIC APPROACH

The best approach to ice is holistic. Use a combination of materials that takes into consideration both the traffic and the plants. If you sprinkle a preventive dusting on the ground before ice forms, you’ll need less salt for shoe and tire traction.

And if you’re planning some plantings along the road, driveway or walkway, choose from plants that tolerate salt. Besides plants native to seashores, other salt-tolerant trees and shrubs include silver maple, horsechestnut, honey and black locusts, poplar, junipers, mockorange, lilac, larch and Colorado blue spruce.