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The effects of deicing salts on landscapes

Quick facts

  • Properly maintaining walks, driveways, parking areas and streets is the best way to avoid the need for deicing salts.
  • Deicing salts should be used only in critical conditions as they can pollute groundwater.
  • Deicing salts reduce the melting point of water and prevent ice from forming.
  • Sodium chloride is the most commonly used product for deicing roads, sidewalks, parking lots and driveways.
  • Deicing salts are toxic to aquatic species and can kill plants through burning and dehydration.
Evergreens are particularly susceptible to deicing salt damage especially when planted close to streets.

Snow and ice removal on roads, sidewalks, parking lots and driveways can make getting around Minnesota much easier during winter. Poorly maintained icy surfaces can cause debilitating falls and car accidents, and even create liability issues.

But before you pull out your deicing salts to make conditions safer, consider the impact of these chemicals on plants and waterways.

How do deicers work?

While regular snow removal reduces the potential for slippery conditions, sometimes ice can build up and create hazards. Deicing salts are applied onto icy surfaces and reduce the melting point of water from 20°F to - 30°F depending on the formulation. This prevents ice from forming.

According to the Minnesota Pollution Control Agency, sodium chloride is the most commonly used product for deicing roads, sidewalks, parking lots and driveways. Other deicing chemicals include magnesium chloride, calcium chloride, calcium magnesium acetate and urea.

Organic additives like corn molasses, beet juice and even cheese brine have been added to some of these chemicals to improve performance and inhibit corrosion.

Dangers of deicing salt on water quality

While deicers improve safety and getting around in the winter, it’s important to maintain hard surfaces properly and use deicers only in critical areas.

  • One teaspoon of salt will pollute 5 gallons of water.
  • Runoff from deicing chemicals results in groundwater pollution, the source of most Minnesotans’ drinking water.
  • Chloride in high amounts affects the oxygen levels and natural mixing of lakes and waterways and is toxic to fish, aquatic bugs and amphibians.
  • Excessive use of deicing salts can degrade concrete, asphalt and natural stone, and corrode metals.
  • Read more about chloride from the Minnesota Pollution Control Agency.

Dangers of deicing salts to plants

Deicing salt harms and ultimately may kill plants. Sodium chloride, the most commonly used deicer in the Twin Cities, causes the most significant plant damage.

Symptoms of salt damage on plants:

  • Dried up and brown needles and leaves.
  • Loss of foliage, buds and branches.
  • Premature plant death.

Salt can be absorbed by plant roots, causing dehydration, and salt spray can burn turf and foliage, especially on evergreens.

Sodium causes clay particles in soil to expand, increasing soil compaction, reducing water infiltration and making it hard for roots to grow. Weeds like Canada thistle, however, grow well in compacted soils.

Select salt-tolerant plants

Choose salt-tolerant plants that die back each year for areas along sidewalks, driveways and streets where deicing salts may be used. Minnesota Plant Lists and The Best Plants for 30 Tough Sites have good choices for salt-tolerant plants.

  • Choose lawn seed mixes and sod containing salt-tolerant fine fescue grasses.
  • Salt-tolerant perennial flowers die back over winter making them good choices along driveways, walks and streets. Replaced each year, annual flowers are also good options.
  • Do not plant evergreens along surfaces where deicing salts are used and can kill needles.
  • Plant trees and shrubs at least 3 feet from driveways and walks where deicing salts are applied. 
  • Plant trees and shrubs at least 7 feet from roadways where salt spray may occur from street maintenance.

Salt and lawns

The spread of deicing salts in the winter can dramatically increase the salt content in soil in turf and ornamental areas near walkways and roadways. High salinity can cause root damage and dehydration in many turfgrass species, resulting in yellowing and death. 

Planting turfgrass along roadways and walkways helps remove pollutants (such as deicing salt), controls erosion, and improves water quality. The short height of turfgrass also helps drivers to navigate roadways safely.

Select salt-tolerant turf

Fine fescues perform the best in high-salinity environments, according to the UMN Turf Department research. Slender and strong creeping red fescue performs the best among turf species in high-salinity conditions, but most seed mixes containing any fine fescue species will perform among the best in high-salinity environments. 

  • Kentucky Bluegrass performs poorly on roadsides with high salt concentrations.
  • Tall fescue has intermediate salt tolerance among turfgrass species.
  • MNST-12 is an approved salt-tolerant mixture, available as both seed and sod and is recommended for areas along roadways or sidewalks that receive higher salt amounts.

Alternative deicing strategies

Sand can increase traction on icy surfaces, but does not melt or remove ice and can block water drainage systems. 

Alternative deicing methods such as beet brine and alfalfa meal have been used to help lessen the adverse effects of traditional salt. While sugar beet brine can effectively lower the temperature at which salts can be applied and reduce the environmental impact of salts, the sugars in beets can also reduce oxygen availability in nearby waterways. 

Alfalfa meal is also an effective deicer and provides traction to ice, but it contains nitrogen, which has the potential to contaminate waterways.

Good maintenance reduces the need for deicing chemicals

  • Shovel, scrape and sweep snow often to remove as much snow as possible to prevent ice buildup.
  • Avoid depositing snow onto nearby shrubs as it may contain salts or break branches.
  • On warm days, let any remaining snow on surfaces simply melt.
  • If needed, apply deicing salts correctly and sparingly to critical areas only.
    • Read the product label and apply the product as directed including at the proper temperature.
    • Do not apply deicers to snow. Remove the snow first.
  • More is NOT better. A coffee mug of salt (about 12 oz.) is all that is needed for about 1,000 sq. ft., approximately the area of a 20-ft driveway or 10 sidewalk squares.
  • Spread salt evenly leaving about 3 inches between salt grains. Avoid spilling piles of salt.
  • Sweep up any salt grains you see on dry surfaces to prevent it from washing or blowing into plants and waterways. Save it in a container to reapply later in the season.

Need professional help? The Minnesota Pollution Control Agency has a list of Smart Salting certified contractors.

Authors: Julie Weisenhorn, Extension educator, Jon Trappe, Extension turf educator and Noah Burley

Reviewed in 2024

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