De-icing Salts Damage Soils, Plants and Water

Brooming caused by  salt spray

January 23 begins Salt Awareness week. With the recent snowfall, you may be using de-icing salt products to keep driveways and sidewalks clear. Excess de-icing salts can damage soils, plants and water sources. It just takes one teaspoon of salt in a five-gallon bucket of water before it starts to create problems. It also is hard on the paws of our furry friends out on their daily walks. 

Excess sodium in soil leads to reduced water infiltration in soils and soil compaction, among other things. Salt gets into our drinking water wells as well. One Madison well will exceed the taste threshold of 250 milligrams per liter of water within the next 17 years.

Salt build-up in the soil can eventually stunt or kill plants. Evergreens, in particular, can be damaged or killed by salt pellets or spray tossed up by snowblowers or shovels. Plants constantly receiving salt spray from passing vehicles are especially prone to damage. Some symptoms include dead twigs (or dead needles on evergreens), stunted growth, eaves with brown margins (usually seen early in spring), dead buds and ‘brooms’ (tight clusters of short twigs) on branch ends. Brooming is especially obvious on trees next to highways. 

If salting is necessary near plants, mix de-icing salt with sand or use an alternative product such as calcium chloride. Dr. Laura Jull of the UW-Madison Horticulture Department wrote a publication titled ‘Winter Salt Injury and Salt-Tolerant Landscape Plants’ on the effects of salt on woody plants as well as salt tolerant woody plants that is available online at . Type A3877 into the search box to view or download this free publication.

The City of Madison Public Works Department uses various techniques, such as spraying liquid brine instead of salt pellets to reduce salt use on roadways. Liquid brine is only about 30% salt and 70% water, which reduces salt use dramatically. The City of Madison recently passed a new ordinance regarding salt use. Under new rules, owners must limit salt use to only what is needed and must remove excess salt left on the sidewalk once snow and ice are gone. Salt is not effective in temperatures below 15°F, so don’t apply unless temperatures are above that. If you hire a private company to help with winter maintenance, encourage them to get certifiedMadison’sWinter Salt Certification Program. For more information on de-icing salt visit

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