Answer: If rock salt (sodium chloride) drains or drifts into the soil alongside the paths, it can harm your plants and rob the soil of nutrients. Ice-melt products made of potassium chloride, magnesium chloride or calcium chloride are slightly less harmful; they are less corrosive and they contain nutrients that plants can use.
If you have to use ice melt, read the packaging closely and follow the directions. Applying the product appropriately should minimize damage. Here are some general guidelines for applying ice-melt products:
- Use the least amount possible to get the job done. Start with a small amount, let it completely dissolve and go to work, then apply more if needed.
- Apply the product before the snow and ice hit, if you are certain they are coming, or just as it starts to snow or sleet. Again, apply only a small amount.
- Don’t bother applying ice melt when temperatures are extremely cold. Rock salt will be effective down to 15˚F. Calcium chloride will be effective down to 5˚F. There’s no product that will work below 5˚F unless you apply it very, very heavily. It would be better to wait for the temperature to warm up some.
Here are some other tips for keeping walkways ice-free and plants safe in winter:
- Don’t put ice-melt products on top of snow. Shovel or snow blow the snow away first.
- If you can remove ice without a melting product, that would be safest for plants. Thin layers of ice can sometimes be chipped or scraped away, particularly if the sun is working on them too.
- Don’t shovel or blow snow directly on top of plants and shrubs.
- Get out and shovel or blow as soon as possible after the storm, so ice has less chance to form. Work in a way that lets you avoid stepping on the snow before you remove it. Ice often forms where people have compacted the snow against the pavement by stomping on it.
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