Tips to choose the right salt to melt ice and stay safe

In 1973, Andy Amrhein started working at a hardware store in Bethel Park, Pa. As a 13-year-old, he would load bags of rock salt for customers during the winter. Back then it was the only product available to melt snow and ice.

Amrhein, who now owns the store, says today there are many other options. The new products are safer for plants, pets and the environment, and they are actually cheaper when applied correctly.

Rock salt appears to be the cheapest choice for a 50-pound bag, but it takes twice as much material than magnesium or potassium chloride and four times as much as calcium chloride to get the job done.

"If you took the time and actually spread it at the right consistency, rock salt is not cheaper anymore," he says. "We're actually selling more safety salt products than we do rock salt."

There are plenty of reasons homeowners are moving away from rock salt, from concerns for a concrete sidewalk to worries about pets to the harmful effect of salt on plants.

"Salt will quickly kill any vegetation," he says. "Any bordering lawn, shrubs, perennials or trees can adversely be affected by exposure to sodium. If the rock-salt residue gets into the soil, it takes 12 months to remediate."

When it comes to pets, Amrhein recommends cleaning the paws of any animal that walks over salt-treated areas. "The magnesium product is the least severe to a pet. Sodium is the worst. Calcium is just a little bit better than salt."

Calcium products work the fastest and are effective to minus -25 degrees. Next in line environmentally is potassium, which stops being effective around 5 degrees. Magnesium is the most environmentally friendly and works down to zero degrees. Rock salt is the least friendly to the environment and will work to about 15 degrees.

So knowing all that, why is salt still so popular?

Old habits die hard, Amrhein said.

"It's generally older men who know everything, and they just flop their $10 and take a bag of rock salt.

"Younger customers all want to be educated. The women have all the patience in the world and demand to be educated. It's funny who you can talk to and who you're wasting your breath on."

Landscape designer Phyllis Gricus owns Landscape Design Studio in Pittsburgh. She has concerns about the use of salt around plants and with what's happening downstream. As snow and ice melt, de-icers enter the storm-water system. When the sewers are overburdened, the storm water makes its way into streams and rivers, where it can poison fish and harm aquatic organisms.

As for plants, salt and salt substitutes change the chemical composition and pH of the soil and cause a nutritional imbalance, she said.

"Salt spray causes bud death and twig die-back in leafy plants and will cause browning and yellowing on evergreens."

For these reasons, she uses an organic de-icer: alfalfa meal. The nitrogen in the meal is what melts the ice.

Gricus first clears the snow and then uses a mesh kitchen strainer to sprinkle the meal on the sidewalk and other areas. Her most important tip: "Be sure to stay upwind or you'll end up with a green meal coating on your boots and smell like you've just left the horse barn."

This is her second winter using the material. When first applied it provides immediate traction and then starts the melting process.

A 50-pound bag is less than $20, and she only uses about a quarter of a bag per season, depending on the severity of the winter. Alfalfa meal can be found at feed and supply stores.

Here's more good news: Not only is it safe for plants, but also it's a wonderful fertilizer.

There are other benefits for gardeners, too. It can be added to the compost pile to help speed decomposition. Alfalfa meal can be steeped in a nutrient-rich tea and sprayed on plants as a foliar fertilizer.

"Spread it around trees, shrubs and perennials. It's good for all flowering plants," she said.

And there's another benefit, too. "It helps plants create larger flowers and increases their tolerance to cold."

Choose carefully when choosing something to melt the snow and be smart about which product you apply.