This or That: What's the Safest Way to Melt Ice?

Salt and sand both boast ice-fighting properties, but each has consequences for your soil and water.

February 8, 2010

Properly deiced sidewalks prevent winter mishaps.

RODALE NEWS, EMMAUS, PA—Snow and ice removal can be affected by budget or morale (who wants to dig out the snowblower yet one more time?), but its effectiveness starts with what you use to melt the ice. Chemical deicers can be marvelously convenient, "set it and forget it" modes of dealing with too much snow, but they don't always work in extremely cold weather. Sand may make it easier to walk to your car, but you need a lot for it to work. So, which is best?


This: Salt-based Deicers

Pros: When deicers come into contact with moisture, they form a brine, which has a lower freezing point than water. That brine does melt some ice or snow, but the primary purpose is to prevent the frozen stuff from bonding to pavement so it's easier to shovel. Standard deicers are made from various forms of salt—sodium chloride (or table salt, a.k.a rock salt when it's in bigger chunks), calcium chloride (that white stuff that looks kind of like styrofoam pellets), or potassium chloride—and two ingredients (urea and calcium magnesium acetate) that are commonly found in fertilizers. Most home-deicer formulations are made with a mixture of those ingredients for convenience and performance, as each one works differently under different temperatures and conditions.

Cons: All that salt can be damaging to plants (salt inhibits the absorption of moisture into the soil), and it can sicken pets who walk through it and lick it off their paws. Some forms of salt, along with those ingredients derived from fertilizer, are particularly hard on concrete. The chemicals can draw water down into a concrete surface, where it freezes and causes the surface to crack. Salt that washes into rivers and streams can increase the salinity of water to the point that fish and marine life begin to die off, and according to the U.S. Environmental Protection Agency, rivers and streams in areas of the northern U.S. that receive heavy snowfall have seen increases in salt concentrations. In some cases, those waterways feed into public drinking supplies, where salt concentrations can put residents at risk for high blood pressure or other heart problems. And, tracked in on the soles of winter boots, salt can stain carpets and floors.

Is there a better alternative to chemical deicers? Read on to find out.

That: Sand

Pros: Unlike deicers, sand is an abrasive, used to create friction between your tires (or shoes) and the icy or snowy surface. It doesn't melt snow, although some melting could occur as a result of the heat generated by friction. Sand has many fewer environmental downsides than salt, and it can be the best alternative if temperatures drop low enough to prevent chemical deicers from working.

Cons: Sand can build up in soil as snow melts, causing problems for your plants come spring, and it's been known to clog storm drains and sewers. Plus, mixed with slush and water, damp sand can lead to a huge mess on your hallway floor.

Which one should you choose? Read on to find out.

This or That?

Go with…both. Mix 'em. While sand is the environmentally preferable choice of the two, it freezes if you apply it directly to icy surfaces, and therefore has to be mixed with salt. But you can still protect your pets, plants, and concrete from the damaging effects of salt by mixing sand with products made primarily from calcium magnesium acetate (CMA), one of the fertilizer-based ingredients that gets mixed in with salts. CMA is made from limestone and acetic acid (the primary component of vinegar) and is generally considered the best chemical to use for safe ice melt, as it has little impact on plants or pets if used as a stand-alone product. If you can't find any CMA in your local hardware store, mix a little beet juice in with your sand and salt. Two communities in Indiana that have been experimenting with this mixture have found that the beet juice reduces the amount of salt needed and poses little threat to nearby waterways.

What ever you use to put Old Man Winter in his place, keep your landscape and pets healthy with these winter-protection tips:

•  Cover your landscaping. While you may opt for something less toxic for your driveway, your city most likely uses various forms of salt to keep streets clear. Cover any plants that border roadways with burlap cloth to protect them from slush or salt sprays. Or, come spring, plant some salt-tolerant plants or bushes that can take a briny watering during the colder months (and serve as protection for less-tolerant plants), such as buckthorn, snowberry, and forsythia.

•  Be sure to flush. In the spring, flush any soil that may have been exposed to salt with two inches of water over a two- to three-hour period, and repeat the procedure after three days, advises the University of Nebraska horticulture department. That will remove most of the salt from the soil and make it healthier for any seeds you want to plant. To gauge the amount of water to use, lay out a pie pan that's two inches deep while you're watering. Once the pie pan is full of water, you know you've watered enough.

•  Wash their paws. Wash your pets' paws off with warm, soapy water after they come in from a walk or romp in the snow, to keep salt from making them sick or drying out their paw pads. Clean floors promptly to keep tracked-in salt from irritating bare animal or human feet, or from wrecking the floor's finish.

•  Wash your wheels. One downside to mixing salt and sand is that abrasive sand can speed up salt's corrosion of car finishes. So, keep a bottle of vinegar handy to keep the mixture from destroying your paint job, especially if your municipality uses sand in its snow-coping efforts.

Tags: lawn care