As long as it's used sparingly, garden fertilizer can be a safe alternative for melting ice. Applying too much fertilizer also can harm plants. Pure nitrogen fertilizer, such as urea, also can be used. It melts ice at temperatures as low as 11 degrees F, and is best applied at temperatures between 25 and 30 degrees. Urea can be applied at a rate of 10 pounds per 100 square feet.
Calcium chloride is a more effective ice melter than fertilizer, but it, too, can harm plants.
Apply one part calcium chloride to three parts sawdust. This provides traction, and when warmer weather comes, you can sweep up the mixture and either compost it or dispose of it in the garbage. Other materials that can be used for traction are gravel, sand, cat litter or cinders.