Chemical Deicers are Gentle to Plants and Vegetation When Used Properly
27 January 2000
FEATURE/Chemical Deicers are Gentle to Plants and Vegetation When Used Properly
--Now that Mother Nature has surprised the East Coast area with up to 2 feet of snow from the recent blizzard, homeowners and commercial building maintenance personnel are frantically spreading chemical deicers to clear sidewalks, paths, and parking lots.
But will there be any residual effect next spring on adjacent soil where flowers, shrubbery, and other vegetation should be growing?
According to research chemists at The Dow Chemical Company, Midland, Michigan, chemical deicers should not harm plant life if they are used judiciously. As a matter of fact, they also point out, four of the main ingredients in most chemical deicers -- calcium chloride, magnesium chloride, potassium chloride, and urea -- are all routinely added to soil to provide micronutrients; the only exception is salt. Of course, even fertilizers can cause vegetation browning or die back if they are over applied.
One common mistake, the Dow scientists say, is the overuse of deicing chemicals. Deicers should not be applied at rates high enough to completely melt snow and ice. This method uses too much of any deicer, is more costly than necessary, and can damage vegetation. The proper way to use any deicer is to apply it at the rate recommended by the manufacturer, wait a few minutes for it to break the bond between the snow/ice and the pavement, and then remove the snow and ice from the pavement.
Iowa State University's Department of Horticulture has conducted studies over a two-year period to evaluate the effects of common deicing products on the turfgrass borders of sidewalks, driveways, and parking lots. Although none of the deicers seriously affected turfgrass quality or color, calcium chloride pellets were shown to cause less change in vegetation quality or color when areas exposed to various deicers were compared to an untreated control area.
One of the reasons that calcium chloride has less effect on vegetation is that it is an especially efficient deicer. Less of it is needed to clear the same amount of snow or ice, thus minimizing the exposure of dormant plants to deicer chemicals. Because it works faster and melts more ice and snow, the recommended application rate for calcium chloride is lower than for other deicing chemicals. This means that a smaller amount of calcium chloride enters the soil since less deicer is necessary to do the same job.
Although calcium chloride is known by many brand names, it can be easily identified as small, round white pellets. Calcium chloride will always be identified, despite the brand name of the deicer, in the list of ingredients shown on the package. Calcium chloride deicers currently available on retail shelves include PELADOW(R) from The Dow Chemical Company, DRIVEWAY HEAT(R) from Prestone Products Corporation, QUICK JOE(R) from Milazzo Industries, and SNO/MELT(R) from Standard Tar Products Company.