Even in mild winters, homeowners need to be prepared for some icy weather. There are a number of ice melt products available to treat slippery sidewalks and hazardous driveway surfaces. However, the negative environmental and other impacts of some deicers leave many consumers wondering which ice melt product is best for home use.
Salt is a common name for sodium chloride (NaCl). It comes in several forms, including the fine-grained table salt used to flavor food and the coarser rock or road salt often used to melt snow and ice. Sodium chloride and other chloride-based salts melt ice by lowering the freezing/melting point of water below 32° F. They can also keep new ice from forming and improve traction.
Many people choose chloride-based salts (calcium chloride, magnesium chloride, sodium chloride) because they’re cheap and available. In Virginia, VDOT uses these compounds to prepare for snow and ice on Virginia’s highways and byways. Calcium magnesium acetate (CMA) is one alternative recommended by Virginia Cooperative Extension. It is a formulation of dolomitic limestone and acetic acid, is effective down to 5°F, and is particularly useful in environmentally sensitive areas. CMA can also be applied in a liquid form to roads and bridges before a storm to prevent snow and ice from bonding to the road surface.
The cost of large-scale commercial application of salt deicers is high. Washington State University has estimated that the U.S. spends several billion dollars on removal of snow and ice from major highways each year, not to mention another $5 billion in associated costs, including damage due to corrosion. Luckily, individual homeowners have small areas to treat with ice melt and can choose an economical product that fits their needs.
Environmental Impacts
Deicing salts can damage or kill our landscape plants and trees. Salts bind with water, preventing roots from absorbing water. They can even pull water from the plant, causing dehydration and displacement of other mineral nutrients. High levels of sodium can also increase soil compaction, reduce water infiltration, and make it harder for roots to grow. Typical plant symptoms of salt damage include dried up and brown needles and leaves; loss of foliage, buds and branches; and reduced or distorted leaf or stem growth. This damage often appears first on the side of the plant facing the road or sidewalk.
Salt and deicing solutions find their way into groundwater and contribute to contamination of both surface water and groundwater. Chloride in high amounts reduces oxygen levels in water and can be toxic to fish, aquatic bugs, and amphibians. In addition, runoff from nutrient-based deicers such as urea pollute local waterways and cause toxic algae blooms that are harmful to aquatic life, people, and pets.
Deicer salts are especially corrosive to metal and concrete. For many years, snow and ice melt products containing sodium chloride were used on sidewalks, roadways, bridges, airport surfaces, and other hardscape infrastructure to keep us safe and to keep traffic moving. But over time, it became obvious that salt and other chlorides react with and damage concrete, steel, vehicles, and other materials and equipment.
Making a Wise Choice
If you are only concerned about melting snow and or ice, traditional ice melt products containing salt usually prove very effective in most climates. Use these products wisely to minimize the environmental impact. Apply deicers sparingly before ice accumulates, and apply according to the label and at the right temperature. A 20-foot driveway needs only a small amount of deicer (a 12-ounce coffee mug full). Target spots where icing is most hazardous and avoid areas within five to ten feet of salt-sensitive plants. Remove snow first and sweep up any leftover salt grains for use later in the season. Never use fertilizers or urea-based deicers.
Remember, more is not better. It only takes one teaspoon of salt to pollute 5 gallons of water.
CMA is considered the best environmentally friendly choice because it is biodegradable, less corrosive, and less damaging to plants. Products containing CMA can be found at local garden and lawn retailers. Although more costly than deicing salts, CMA used in small quantities for home driveways and walkways is reasonably affordable.
If you are unable to obtain CMA, or if you find it too expensive, consider using an alternative that provides good traction, such as sand, salt mixed with sand, kitty litter, or bird seed. Covering small areas, like steps, with a tarp in advance of a storm or reducing the area that is treated are also options.
When comparing costs against investments in caring for your property, it makes sense to try a product that safely melts snow and ice and that has been proven to lower risk of damage to your plants, landscape, and groundwater. This is especially the case for those of us who have spent many hours, if not years, nurturing our gardens and yards.
Need more information? Review the pros and cons of using various deicers for snow and ice melt from these online resources: rock salt damage to plants and trees and alternatives to using salt.
References
“Choosing Appropriate Ice Melt Products” , Goatley, Mike, Turfgrass Extension Specialist, Virginia Tech, Virginia Cooperative Extension, 3 Dec 2012.
“Explained: The Science Behind Ice-Melt Products”, Case Western Reserve University, 23 Jan 2023.
“Managing Salts in the Home Garden”, Stott Lance, SDSU Lecturer and Burrows, Rhoda, Professor & SDSU Extension Horticulture Specialist, South Dakota State University, Apr 2020.
“Watershed-friendly Deicing” , Mansberger, Justin, Extension Educator, Water and Master Watershed Steward Coordinator, Penn State University, Penn State Extension, 1 Mar 2021.
