Salt can cause problems for gardeners, especially if they live in a northern climate and use salt to clear ice from driveways or sidewalks.
There are many de-icing compounds on the market, and while they all set out to do the same job, there are some that are more friendly to lawns and other plants growing in the garden.
When shopping for de-icing agents, read the package label for ingredients. It may not be wise to choose the cheapest one on the shelf.
Rock salt or sodium chloride is the most commonly used ice-melting product. It is the least expensive and will work at temperatures as low as 5 degrees F. However, it is very corrosive on metals such as snow shovels and reinforcing rod in driveways. And it is extremely harmful to plant material in the landscape. It will damage plants and it is also detrimental to soil, making it denser and less permeable to water movement.
Safer alternatives, especially where plant material is concerned, are materials made with calcium, magnesium or potassium chloride.
Of the three, magnesium chloride is considered to be one of the safest to use in the landscape and it works when temperatures fall to minus 20 degrees F.
Unfortunately, these materials are more costly than sodium chloride.
Another way to minimize salt damage to the landscape is to use less of it. Although kitty litter, sawdust and sand won't melt ice and snow, they can help provide traction on slippery surfaces.
The amount of de-icing compound used can be minimized by mixing it with sand. Fifty pounds of sand mixed with one pound of de-icing compound is effective and less damaging to plants and the soil.
There are also liquid solutions on the market, such as potassium acetate, that can be used to help manage ice. It can also be made by dissolving a small amount of de-icing compound in enough hot water to melt the solids. Use a plastic hand pump sprayer to apply the liquid to small surfaces such as porch steps.
Salt from highways is another source of potential damage to evergreens and shrubs. Winter storms result in tons of salt added to the roads and sidewalks each year. When snow is cleared, it often ends up being sprayed, shoveled, and piled on trees, lawns, and perennial beds.
Just as salts cause vehicles to corrode, it can also create problems for landscape plants.
To prevent salt damage, do not plant closer than 50 feet from the road. If this is not feasible, screens of fencing or burlap can be used to deter salt sprays. The most effective way to protect vulnerable plants is to erect a burlap or similar screen near the shrubs to keep the salt spray off the plants. If left in place all winter, the screen can significantly reduce salt damage.
Salt accumulation in the soil can also damage plants. This happens when salt-laden snow is plowed from streets and is piled up. When the snow melts, it moves the salt into the soil.
The symptoms of salt injury include stunted yellow foliage, premature autumn leaf coloration, death of leaf margins, and twig dieback. On evergreens, needles may turn yellow or brown in early spring.
Salt damage is often confined to branches facing a street. Many plants can recover from an occasional salt spray. If it is a yearly occurrence however, death of the plant may result.
Salts not only injure plants directly but also can change the structure of the soil, causing the soil to become compacted.
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. This helps to leach the salt in the soil away from the root zone of the plant.