How Ice Melting Products Affect Your Landscape
Learn what ice melting products have to offer, and how to identify and repair salt damage in your landscape.
Stay On the Safe Side
In winter you work hard to keep your home and your family safe by clearing ice and snow from walkways and the driveway. Safe access means no slips or falls for you and your guests, and it is also important for any unexpected visitors like the furnace repairman or (let's hope not) an ambulance crew. The peace of mind that comes with sure footing is worth every penny spent on supplies. For many of us, in addition to shovels and snow throwers, ice melting products are part of the standard equipment for winter weather preparedness; but these chemicals can take a toll on landscape plants. Proper use and a few follow up procedures can, however, minimize or eliminate the damage done to your landscape as you meet winter’s challenges.
Know Your Options
There are lots of brands to choose from, but only a few ingredients in ice melting products. There are blends of these ingredients available, as well as brands that do not list their ingredients. It is always good to know what is in the bag. This is a list of the common ingredients in ice melting products and some of their characteristics.
- Magnesium Chloride is environmentally friendly and safer for use around pets. It is effective to -13 degrees.
- Sodium Chloride (rock salt) is very inexpensive and works extremely well to about 20 degrees. It is the product most likely to damage plants and pavement.
- Potassium Chloride is environmentally friendly and safer for pets. It works to about 25 degrees but its use is becoming somewhat limited due to market demands for potassium.
- Calcium Chloride works very fast and is effective to at least -25 degrees. It leaves a brine slush that dries slowly.
- Calcium Magnesium Acetate (CMA) is environmentally friendly and works well to 20 degrees. It is primarily used in contractor settings like parking lots and streets.
These elements are all naturally occurring, with the pricing differences being due to differences in availability and or demand. Magnesium is damaging to concrete to a greater degree than non-magnesium products. Chloride products are all corrosive to some degree. Do not apply ice melter to wood (decks, etc.) or concrete that is less than a year old. It is important to use and store these products according to manufacturer’s directions.
A few guidelines will help to minimize collateral damage to your landscape while using ice melting products. The main points are using the proper amount and spreading it evenly. Remove the snow first, only use these products to melt the final remnants. To apply ice melters, use a calibrated hand held or walk behind spreader. This will ensure proper, even coverage per the manufacturer’s instructions. For better traction, don’t apply extra ice-melt...use kitty litter, coarse sand, perlite or some other gritty substance.
Too Much Salt
Rock salt is by far the leader in causing landscape damage both in the soil and via wind driven salt spray. When dissolved in water, the sodium displaces the plants’ needed minerals in the soil, and the chloride is absorbed through plant roots and carried to the leaves to wreak havoc on its metabolic processes. Above ground, the salt’s drying effects work directly against plants’ abilities to withstand cold, dry winter conditions by damaging leaves and twigs. Salt damage appears gradually on evergreens as dead needles, usually on the side facing the street. On lawns, it appears as dead patches, usually in low areas where street or driveway water drains. Deciduous plants may have twig dieback or tan-brown leaf margins when the leaves emerge in spring.
Repair Salt Damage
Even if you use a non-sodium ice melter, runoff and spray from nearby roads can affect the landscape. The good news is that the effects can be reduced or repaired. When the weather warms, flush salt from landscape foliage with water. Well-drained soil can be treated similarly by irrigating several times on a regular schedule, however there are times when salt damage still appears. Gypsum can help repair salt damage, particularly on clay soils that do not drain well, and works best if applied after core aeration. Gypsum dislodges the sodium, allowing the normal soil structure to be restored. It is available in garden centers and home improvement stores, typically sold in bags like lime.
Be prepared this winter. Make sure your snow removal equipment is in good repair, and buy your ice melt before the weather turns. Knowing the the abilities and limitations of your ice melting products will also help you keep your landscape in good order. Stay warm!