Gardening Tips: January 29, 2013
Salt Alternatives for the Homeowner
It is minus eight degrees with the wind-chill at minus 25 as I write this from my chilly, (53 degree) living room on January 22. I have to drive to Walton today and I will be wary of any “wet” spots on the highway, since they will surely be black ice. Thank goodness for road salt!
It is not uncommon in the Capital District/Hudson Valley region for heavily traveled roads, such as the Thruway, to receive 40 to 80 tons of deicing salt per lane mile per year. That works out to about 15 to 30 pounds per linear foot. It is surprising that any roadside plants can tolerate that much salt, but most do. If they received a fraction of this much salt during the growing season, the roadsides would be devoid of vegetation. There is little the homeowner can do to change the road salt situation but there are some alternatives to salt that may be used in the home environment.
Tough on plants
Road salt or deicing salt is mostly unrefined rock salt, containing about 98.5 percent sodium chloride. Calcium chloride is sometimes used when temperatures are extremely low (Rock salt is useless at temperatures below + 10) but it is about eight times as expensive as sodium chloride. Rock salt causes injury to plants by absorbing water that would normally be available to the roots. Even when moisture is plentiful, excess salt can create a drought like environment.
In addition, when salt is dissolved in water it breaks down into sodium and chloride ions. Roots readily absorb chloride ions and then they are carried through the sap stream to actively growing portions of the plant such as leaf margins and shoot tips. High levels of chloride are toxic and result in characteristic marginal scorch patterns. (Brown edges around the leaves) Excess sodium in soil also hurts plants by encouraging soil compaction, leading to restricted uptake of oxygen and water. Calcium chloride is not nearly as damaging.
Plants most likely to be affected in the home landscape are those that receive lots of salt laden snow. For example, if you routinely apply salt to your porch or steps or deck, the plants growing nearby are most at risk, especially if you shovel snow on top of their root systems. Likewise, plants along your driveway or roadside are more at risk then those in the backyard. So what are the alternatives?
Choose calcium chloride
First, buy calcium chloride instead of rock salt or purchase one of the newer deicing materials that are reported to be even less toxic to plants. In recent years several new products have been developed that are very effective at melting snow and ice.
These new products are quite expensive but so are replacement plants! If you just want to improve traction, try using sand or kitty litter or even fine gravel. Keep in mind however that you will most likely be tracking these materials into the house along with the snow on your boots. Never use soiled kitty litter for this reason! Wood ashes have also been used for traction, but too much wood ash spread over your plants can raise the soil pH to damaging levels. Wood ash will also be carried in the house with the snow on your boots and it leaves an unsightly gray residue.
I will no longer need any kitty litter, as I lost my beloved cat two weeks ago. My friend Lester Gass shared this quote with me that he attributed to a woman named Amy Ahberg. “Taking on a pet is a contract with sorrow.” Indeed it is. — Bob Beyfuss