Which deicer is best to use near grass and plants?

I was asked recently which deicer is safest to use near grass and other plants. I’ve dug into this question to help you make a more informed decision.

Most ice melt products contain some form of salt. Chemical deicing works because solutions containing salt will freeze at lower temperatures than pure water. Pure water freezes at 32 degrees. Water with salt dissolved in it freezes at temperatures below 32 degrees. Once a deicing compound is applied to a surface, it melts the ice, creating a brine solution with a freezing point lower than that of pure water. This works until the melt water dilutes the salt solution to a point where it refreezes.

Most of the popular de-icing products sold in stores are chloride-based, each containing a different combination of salt.

Sodium chloride is the cheapest and most common ice melt. It is effective at melting ice when temperatures are 12 degrees or higher. It is harder on plants than calcium and magnesium chloride. However, sodium and potassium chloride residues are easier to remove from floors and carpets.

Calcium chloride has the lowest temperature threshold, working to -25 degrees. It is safer for plants than sodium chloride. It is typically more expensive than sodium chloride products. Calcium and magnesium chloride can have an oily residue that is more difficult to clean when tracked indoors.

Magnesium chloride products are effective to 5 degrees. It is similar to calcium chloride in cost, but between sodium and calcium chloride in safety around plants.

Potassium chloride salts are the least effective, melting only to 20 degrees. It is also harder on plants than calcium and magnesium chloride. This is the least effective option for use in Idaho.

All these chloride-based products can be damaging to plants. Using excessive deicer is unsafe and won’t be any more effective than smaller amounts if temperatures drop below the product’s minimum threshold. If you follow recommended rates, any deicer can be used with minimal damage to surrounding vegetation. However, if you have plants sensitive to salt or if salt accumulates in certain areas, any of the products can be damaging.

There is a newer product made up of calcium magnesium acetate. It is better for the environment because it does not contain chloride and is biodegradable. This product will work to about 15 degrees, but it is much more expensive than any of the chloride-based products.

Nonchemical products like wood chips, ash, sand, bird seed, cat litter and sunflower seeds don’t melt ice themselves. They help provide traction on slippery surfaces and offer melting during the day as their dark colors absorb warmth from the sun.

Some products are sold as pet-friendly. This benefit can often be considered a trade-off. Excessive exposure to salt-based products can be hard on pets’ paws. However, products that are “paw-safe” may be even more unsafe for your pet than salt-based products if ingested. Others contain urea, a form of nitrogen used in fertilizer. Runoff containing nitrogen can pollute waterways and is not recommended.

Regardless of product used, take the time to remove as much snow and ice as possible before applying a de-icing product. Use only what you need and clean up excess when it is no longer needed.