MAINE:–(ENEWSPF)–January 18, 2012. Here’s a breakdown of various products available for use, with a review of whether or not they’ll harm your landscape: http://www.safelawns.org/blog/index.php/2011/01/calcium-based-ice-melt-is-safer-for-lawns/
ROCK SALT — This is among the cheapest of the products that actually melt the ice, but it’s also among the most harsh things you can apply to the lawn and garden. When the sodium chloride dissolves, the sodium can burn the grass (see photo, above) and the feeder roots of trees, shrubs and perennials. The landscape can probably survive one or two applications of rock salt throughout the winter, but you should try to avoid any more than that. Don’t even bother to use it if temperatures are much below 20 degrees Fahrenheit. The salt will just sit there and not melt a thing.
CALCIUM CHLORIDE — This basically functions just like sodium chloride by melting the ice, but with the primary component being calcium the plants actually can benefit from a few applications. This is usually more expensive, depending on the source, but it’s worth it for your landscape and even your pets — which can get sick from licking too much salt. This product works at the lowest temperature range of any melter, down to 25 below zero.
CALCIUM MAGNESIUM ACETATE — This alternative calcium derivative combines dolomitic limestone and acetic acid in an environmentally friendly formula that apparently has no corrosive properties at all. It’s pricier than rock salt — about $20 for a 50-pound bag at my local hardware store. But my plants near the walkways are worth a lot, too, so this is what we usually keep by the door when I don’t use some of the free stuff, below. If the temperatures are below -5 to -10, this product doesn’t seem to work all that well.
MAGNESIUM CHLORIDE HEXAHYDRATE — This is the stuff many airports use on the tarmac and many state highway departments are beginning to bring in. It’s also the active ingredient in many so-called pet-safe products. (NOTE: SEE COMMENT CONCERNING CADMIUM, BELOW)
LAWN FERTILIZER — In a pinch when it’s not too cold, you can use your lawn and garden fertilizer as a de-icer and traction aid — especially if the product contains relatively high levels of nitrogen. As the product dissovles, the nitrogen will melt the ice. Don’t use this more than once or twice a winter, though, because too much nitrogen will burn the lawn, too.
SAND, GRANITE DUST OR WOOD ASH — When I just want to increase traction, I spread the free stuff. All of this tracks into the house and creates its own cleanup nightmares, but if people are coming by for a visit, the cleanup is far better than having someone fall.