When your driveway and walkways are covered in ice, you need to move quickly to remove it for safety's sake. Applying a deicer preventively after clearing walkways is an even better course of action. But which product should you buy?
Although all deicers work on the same principle -- decreasing the temperature at which water freezes -- all "salts" are not the same.
Determining which deicer is "best" requires more thought than simply figuring out which is most effective at melting ice.
It's best to stay away from sodium chloride. It's the cheapest rock salt available, but it's the worst for your pets, plants and the environment. It has the potential to kill plants and trees, and can corrode cars, crack concrete and asphalt, and poison wildlife. Don't do it.
Calcium chloride is a better option, and is quite effective in cold temperatures, but be aware that while it's safer than sodium chloride, it still isn't ideal. You'll see it marketed as "pet safe" because it isn't as harsh as sodium chloride, but it still can cause irritation to pets' paws, so be sure to rinse them off and wipe them down if your pet walked over it. And protect your own paws by wearing gloves when handling it.
Potassium chloride -- yes, the same potassium chloride that's a component of all balanced fertilizers (it's the K in the N-P-K ratio listed on packages) actually can harm or even kill plants when applied at rates high enough to melt ice.
Magnesium chloride works well in even colder temperatures, down to about 10 degrees below zero. It dissolves readily to coat ice and melt it quickly, and isn't as likely to burn pets' paws. The downside? It can cost up to twice as much as calcium chloride.
Always apply the least effective amount when using any of the chloride products. Although they do so to varying extents, all of them hold the potential to damage masonry. Applying a waterproofing sealant to driveways and walkways during warmer weather will offer protection from ice-related cracks for several years.
A strange (but unproven as a home remedy) method is actually in use by some municipalities around the country: sugar, beet juice and molasses. When combined with any of the salts -- which can be used in lesser quantities than if applied alone -- this syrupy concoction is said to make the salt more effective at even lower temperatures. What's more, it's sticky, so it adheres the salt to the pavement, eliminating the kick back that dings passing cars. It's probably not the best option for your driveway, but it's interesting nonetheless.
Want the greenest option? The one that's best for pets, plants and groundwater? Stick to plain, non-clumping clay kitty litter or sand. It won't melt ice, but it will provide some traction to reduce slipping.
Regardless of how you choose to keep ice at bay, it's imperative that you do so without procrastinating. I had a bad slip-and-fall in my own driveway last winter and still haven't fully recovered from a torn ligament, fractured ankle and broken foot. Keep a supply of your chosen product on hand at all times to ensure you can act quickly.