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GARDENING IN DECEMBER PART #1
BY GEORGE EDGAR
The first few days of Thanksgiving week we had rain in
With the ice, I saw a lot of de-icing products being put on the
sidewalks and driveways. Make sure you select the right product to melt
the ice and follow the label directions in order to make the walkways
safe and avoid plant injury.
The four most common
products are: 1. “Sodium chloride
(NaCl).” This chemical, commonly referred to as rock salt, is the most
prevalent deicing chemical, and in general, has the lowest price tag of
all deicers. An estimated 10 to 14 million tons will be used yearly on
roads in the 2. “Magnesium
chloride (MgCl).” MgCl is usually sold in a 30 percent concentration
with an associated freeze point of 3 degrees F. 3. “Calcium
chloride (CaCl).” Available in flakes, pellets or liquid, CaCl produces
an exothermic reaction, giving off heat. Because of this, it often
performs better than many other deicing salts, especially at lower
temperatures. Some highway departments spray liquid CaCl over rock salt
to lower its melting temperature. The practical melting temperature is
typically considered to be approximately minus 10 degrees F. 4. “Potassium
chloride (KCl).” KCl is similar to or equivalent to potassium based
fertilizer products. It is often promoted as beneficial to plants. The
product as a deicer doesn’t work unless temperatures are more than 25
degrees F. As a stand along product it is relatively expensive and more
often is seen as part of a deicer blend. (1)
A NebGuide from the University also includes other products but
says that urea, ammonium sulfate, and other Nitrogen salts are rarely
used as deicers because of the potential for nitrogen runoff and
leaching into water sources. In many areas nitrogen salts are not
approved for deicing because of these environmental concerns. This
NebGuide also has a list of trees and shrubs and their tolerance for
salt in the soil. (2)
Abrasives such as sand, cinders, and ash have relatively few
impacts on the environment or plants. However, these materials do not
melt ice but do improve traction on slippery surfaces. The disadvantage
of these materials is that they can track into the house and accumulate
in the landscape, and may require removal after the de-icing season.
Regardless of what product you use, be sure and check the label
for what products are in the bag, how much of each, how to apply, and
how often it can be applied. Copyright 2015 (1) (2) A list of
plants with their salt tolerance is available in UNL Extension’s
NebGuide #1121-Winter Deicing Agents for the Homeowner.
(http://extensionpublications.unl.edu/assets/pdf/g1121.pdf) |