Correctly Choose and Use Deicers To Keep Them From Harming Plants

Deicers should not be used to completely melt snow or ice, but to make it easier to clear them away. They work by melting down through ice or snow to the hard surface, where they spread out underneath. For quickest and most effective ice penetration, purchase deicers in uniformly shaped spherical pellets of about one-sixteenth to three-sixteenths of an inch. Irregularly shaped particles tend to melt randomly in all directions, and flakes melt as much horizontally as they do vertically.

Before using a deicer, be aware of the way it affects plants, animals, concrete and other surfaces. Excess salts and fertilization from deicers prevent plants from getting nutrients and from absorbing sufficient water. Symptoms of salt injury are desiccation, stunting and dieback.

Leaf tips and margins appear burned and roots may be injured. The most common injury to concrete is scaling, in which small flakes of mortar and concrete come loose from the surface.

Accumulation of salt in the soil over several years may cause progressive decline and eventual death of plants, so flush the soil with large amounts of water after the last freeze in areas where deicers were used. This is the best way to remove salt from the soil.

Protect plants from injury by direct exposure to salt spray by covering them with burlap or saran cloth to decrease the amount of exposure to slush during snow removal. Always read and follow label directions when using deicers or other products.

Commonly used deicers include:

• Sodium chloride, also known as rock salt and table salt, which has been used as a deicer for many years and commonly is used on roads. It is relatively inexpensive, but can burn plants and corrode metal and concrete.
• Calcium chloride, which gives off heat in an exothermic reaction, often causing it to perform better than many other deicing salts especially at lower temperatures. It is less damaging to plants than sodium chloride.
• Potassium chloride, which is a naturally occurring material used as a fertilizer and food salt substitute as well as a deicer. Its high salt index can burn foliage and inhibit rooting.
• Urea, a synthesis of ammonia and carbon dioxide, which mainly is used as a fertilizer. It has a lower burn potential than potassium chloride and is a source of nitrogen fertilizer. Adjacent turf may green and grow excessively in spring. If urea stays on top of the soil, it quickly breaks down to ammonia and escapes into the air.
• Calcium magnesium acetate is a salt-free melting agent that is used as an alternative to salts in environmentally sensitive areas. It has little impact on plants, animals, metal and concrete. When absorbed into the soil, it is beneficial to soil structure.

Source: Jay Fitzgerald, University of Nebraska—Lincoln