Rock salt is commonly used as a deicing agent, helping prevent winter accidents on roads, driveways and sidewalks. Road crews often add rock salt as a preventative measure when wintry weather is predicted. The same qualities that help the salt break through the ice make it deadly for your lawn. In addition to harming your existing lawn, rock salt can keep grass from growing for years. Moisture Salt removes the moisture from the soil, keeping it from getting to your lawn's roo