University of Illinois Extension

Hold the Salt, Please

Salt can be a problem in the diet of many people. It can also be a problem in the landscape, especially if you are a northern climate gardener wanting to rid your driveway or walk from ice.

Greg Stack

"It won't be long before our attention is turned from the beautiful fall foliage to a landscape that turns suddenly white with the first snowfall," said Stack. "And with that comes the job of keeping the path to your door safe and ice free."

There are many deicing compounds on the market and while they all set out to do the same job, there are some that are a bit more friendly to lawn grass and other plants growing in the garden.

"When shopping for deicing agents it's a good idea to read the package label and find out what's inside because not all deicing agents are made the same and it may not be wise to chose the cheapest one on the shelf," he recommended.

Rock salt or sodium chloride is the most commonly used ice melting product. It is the least expensive and will work at low temperatures (five degrees F.) However, it does have its drawbacks. For one it is very corrosive on metals such as snow shovels and reinforcing rods in driveways. And worse, it is extremely harmful to plant material growing in the landscape. Not only will it damage plants it is also detrimental to soil making it more dense and less permeable to water movement.

Shoveling Snow "Safer alternatives, especially where plant material is concerned are materials made with calcium, magnesium or potassium chloride," he said. "Of the three, magnesium chloride is considered to be one of the safest in regards to its use in the landscape and they work when temperatures get down to around minus 20 degrees F. Unfortunately these materials are more costly than sodium chloride."

Another way to minimize salt damage to the landscape is to not only use less damaging material but to use less of it. While kitty litter and sand won't melt ice and snow, it can help in providing traction on slippery surfaces. Another way to minimize the amount of deicing compound you use is to mix it with sand. Fifty pounds of sand mixed with one pound of deicing compound is effective and less damaging to plants and the soil.

"There are also liquid solutions used to help manage ice and they are usually more effective than the dry product," he said. "Liquid potassium acetate is one product offered on the market or you can make a suitable alternative by dissolving a small amount of deicing compound in enough hot water to melt the solids.

"One such mixture calls for two parts of water to one part of magnesium chloride. Use a plastic hand pump sprayer to apply the material to small surfaces such as steps."

Salt Damage on YewsSalt spray from highways is also a source of potential damage to evergreens and shrubs. If you live along major highways that are frequently salted, the most effective way to reduce damage to valuable plant material is to erect a burlap or similar screen near the shrubs to keep the salt spray off the plants. Left in place all winter it can significantly reduce salt damage to plants along the highway.

Salt accumulation in the soil can also damage plants. This type of condition usually comes about when salt-laden snow is plowed from streets and piles up over the winter. When the snow melts it moves the salt into the soil.

"Usually the best way to move the salt out of the root zone of the plant material nearby is to apply large amounts of water to the soil," he said. "This helps to leach the salt in the soil away from the root zone of the plant.

"So, while deicing agents are a fact of life in northern areas of the country they don't have to spell death and injury to plants in the vicinity. Check labels for the most plant-friendly materials and use it in a way that limits the quantity applied."