Deicing Impacts on Plants, Dogs, and Sidewalks

Posted by Mark J. Platten, Teller County Extension Director

It is that time of year again where snow and ice become part of the landscape…and covers our sidewalks and driveways.  Colorado Springs was covered in a thick layer of ice this past Saturday evening and, while I enjoy skating in a rink, it’s not appropriate on the sidewalks or roads!  In this post, we’ll be looking at different types of deicers and some considerations on how they might affect plants, animals, and even concrete.

Colorado Springs Ice Storm

Deicers are primarily salt-based products that melts, or prevents, the formation of ice and does so by lowering the freezing point of water and preventing a bond between ice and hardened surfaces. The most problematic element in these salts is chloride, which is a corrosive ion that damages metal and concrete and is toxic to plants.  Here are some common products that you’ll find on the market, courtesy of my cohort Alison O’Connor in a previous post:

Sodium chloride: It’s the most widely available and the cheapest. It doesn’t cause corrosion to concrete, and melts ice best when temperatures are in the 20s. It is the most damaging to plant material. If you use this product, use sparingly and in small amounts

Potassium chloride: Our salty fertilizer friend. It’s expensive and not as widely used as a deicer because of rising costs of fertilizer. Works best when temperatures are above 15 degrees F. Because it’s most commonly used as a fertilizer, it’s relatively safe to apply near plants.

Magnesium chloride: It’s the most common product used on our roadways before storms (applied as a “brine”), because it lowers the freezing point of soon-to-arrive precipitation. It can melt ice down to -15F, which is a nice benefit. If applied in moderate amounts, it’s relatively safe for plants and pets. Its corrosion potential is low, as is its pollutant possibilities.

Calcium magnesium acetate (CMA): It has low corrosion potential, so it’s less damaging to cars, metals, sidewalks and plants. Notice it’s not a chloride product…the “salt” comes from the calcium-magnesium mix and the acetate replaces the chloride.  Plus, it’s biodegradable! Its ice-melting properties are equivalent to traditional deicers, but the cost will make you gasp; it may be 20-30 times as expensive as sodium chloride products. The negatives:  it reacts with and corrodes zinc, so it would affect galvanized steel; it requires more material relative to salt to get comparable ice melting (20-70 percent more by weight); and does not perform as well as chloride-based deicers at temperatures below 25°F during heavy snowfall and freezing rain events.

Dogs and Deicers:

Sodium chloride:  Ingesting a large quantity of sodium chloride can be deadly for dogs; mild ingestion will at least lead to gastrointestinal upset. Salt can also irritate dogs’ paws.

Potassium chloride: Is severely irritating to dogs if ingested.

Magnesium chloride: Sold in crystal and flake form, magnesium chloride is a very popular deicer. It can cause stomach problems if ingested in large amounts, and particularly dangerous for dogs with renal disease who are sensitive to large amounts of magnesium.

Calcium salts (calcium carbonate, calcium chloride, and calcium magnesium acetate): Calcium salts are the most hazardous of all ice melts. Ingestion can cause major gastrointestinal distress, and they are most likely to cause external irritation on skin and paws.

My Dog Henry

“Pet-safe” deicers are typically made with an ingredient called urea. Urea is less toxic than other deicing ingredients, but it can still cause issues if not processed specifically for pet safety. Remember to always check the label; the product should be salt- and chloride-free, and labeled as kid- and pet-safe (if it is not safe for kids, it is not safe for your dog).  Sand and kitty litter are safe for pets as well, and though they don’t melt the ice and snow, they adhere to the ice and make it less slippery and are safe for plants.

Before using any product, clear away as much snow and ice as possible. Get out your shovel and do your best. If heavy snow is predicted, then try to shovel more frequently. Chemical deicers come in various forms—pellets, flakes, and liquids—research shows that pellets from 1/16 inch to 3/16 inch in size work the fastest. Regardless of the type, overuse causes problems. Use only as much as necessary and spread out evenly. Placing deicers in a pile is not a good idea on any level!

Pile of Salt on Sidewalk

Remember, deicing products are not meant to melt all snow and ice but aids you in your removal efforts. Also, consider where you are shoveling the snow.  If you place it downhill from the sidewalk, you don’t have to worry about it creating additional problems as it melts and possibly re-freezes.

Hopefully you feel better informed about your choices and have a safe rest of the winter!

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