This product is calcium chloride or CaCl. It works in extreme cold and while “safer on lawns and concrete’ when over-used or used repeatedly it can damage both. ANDREW MESSINGER
Safe Pet is an ice melter that won’t burn your pets paws and is somewhat benign for plants and hardscapes as it’s mostly urea, a component in some nitrogen fertilizers. ANDREW MESSINGER
Tube sand is nothing more than sand in a tube. It tends to be very coarse which makes it great for traction on driveways and walkways without damaging plants or roots. ANDREW MESSINGER
This product is magnesium chloride. It’s the most expensive ice melter and not always available but it’s the best material to use when you want a material that’s easy on hardscapes and plants. ANDREW MESSINGER
One stop on the garden tour will be at this home in Water Mill on Mecox Bay. COURTESY ABBY LAWLESS
We survived the deep freeze of the winter of 2017-18, and had the traditional January thaw, only to be followed by another, less severe freeze.
The snow gets shoveled away, the ice forms on the walkway and driveway, and out comes the ice melting chemicals that make everything under tire and foot safe for awhile. Then it freezes again and more melting chemicals are added. We remain safe. Our plants, on the other hand, often get poisoned, killed or severely burned.
With this in mind I thought it might be a good idea to review the various ice melters, their drawbacks (yes, some have benefits) and a few thoughts for getting some safe traction around the property.
First, let’s talk traction. Here we’re concerned with safety under foot and not so much with melting. The solution here is simple and it has no effect on our plants. It’s sand. Available in bags and tubes, there are actually several types of sand and some work better than others. The best sand to use for traction is coarse sand sometimes sold as “traction” sand. The sand particles are angular in shape so they tend to lock instead of rolling off the surface. Playground or sandbox sand as well as our beach sand has much smaller, rounder particles and offers much less in terms of traction and stability. Builders sand falls somewhere in the middle and is acceptable if the coarser traction sand isn’t available. Coarse stone dust is also a good substitute. When desperate there’s always simple, cheap, basic kitty litter.
Next we move to the melters. We use lots of chemical ice melters that kill our plants, but there are ways to beat the ice without beating up your plants and at the same time you may cause less damage to your flagstone, blacktop and concrete as well.
If your concrete patio or sidewalk is new, the professionals suggest that you refrain from using any chemical de-icers, as their use may result in scaling (surface separation) of the concrete. Instead, clean off as much loose snow as possible before it turns to ice and use sand instead of melters.
In other circumstances, there are a number of de-icers that you can take advantage of, starting with good old salt (sodium chloride). Sold as table salt, rock salt, ice cream salt (and water softening salt) it is the most used and least expensive de-icer. Remember though that this material works only when the surface temperature is above 10 degrees F and it will definitely damage and can kill adjacent turf, shrubs, trees and possibly bulbs and dormant perennials. Be careful when applying salt, as blowing salt dust can do damage to evergreen plantings many feet from where you put the material down. You see this quite often when road sanders put salt down near pine trees and the pines “mysteriously” die the following spring. The most obvious first symptom is that they quickly brown on one side only—the road side. However, the most severe damage doesn’t show up until the growing season.
Remember also that salt is corrosive to metal. So after applying it, clean your tools and spreaders carefully. Salt should be applied at the rate of about 1 to 2 pounds per 100 feet. Don’t forget that when salt brine dries, it turns to a white powder that may be tracked indoors, where it may do more damage.
Calcium chloride (CaCl) melts snow and ice faster than salt and remains effective to nearly 60 degrees below zero; however, it is more than twice as expensive as salt. It has substantially less effect on plants, lawns or shrubs, but it is not benign and is corrosive to metals. Apply at a rate of about 1 and 1/2 to 3 pounds per 100 feet.
Calcium magnesium acetate (CMA) melts snow and ice just as effectively as the chlorides, does not corrode surfaces and is less toxic to aquatic organisms. It is the melter of choice if you live near a stream, pond or other body of water. It is much more expensive than salt or CaCl, but this may be offset by the reduced costs of damage to infrastructure, tools and equipment. It can also be hard to find. In many areas, liquid forms of CMA are used to pre-treat surfaces just prior to expected snow or ice and is referred to as an anti-icing treatment. This use often means sanding isn’t necessary, since the precipitation rarely refreezes. If you need a visualization of the various properties of ice melters there is a comparison chart here: http://bit.ly/2CAGRNo.
There has also been a great deal of advertising for various liquid ice melters that can be applied prior to snowfall. These work great when used by highway departments, but they’re not terribly effective when used at home and the spray drift can kill plants very effectively.
Some fertilizers can also be used as ice and snow melters. The potassium component of fertilizers (potassium chloride) is what melts the ice, but remember that this too is a salt and overuse can cause burning to plant roots. Nitrogen in the form of urea also has melting action. Fertilizers are more expensive than salt or CaCl and require greater quantities for the same results. Those containing ammonium nitrate are chemically corrosive to concrete and should not be used and fertilizers are effective only when the surface temperature is above 20 degrees.
Urea does a good job, though it’s expensive. It is effective only above 11 degrees F, but is most effective between 25 and 30 degrees. When appropriate, it is the melter of choice in areas adjacent to landscapes as it does not harm, and may be beneficial to plants. It is applied at the rate of from 3 to 6 pounds per 100 square feet.
Another alternative is the fertilizer Milorganite. This natural product is black in color and thus absorbs heat from the sun when used during daylight. For this reason and because of its chemical composition it has some ice melting ability but it can also double as an abrasive and it’s the only one of the group that’s also a deer repellent. Also remember that come spring, any place where it’s been used will get a special green up instead of a die back due to its organic nitrogen component.
We do know that certain plants are absolutely intolerant of salt damage from de-icing and they are: American elm, linden, apple, beech, boxelder, boxwood, flowering quince, ginko, ironwood, hickory, hornbeam, mimosa, red, silver and sugar maples, sycamore, Douglas and balsam fir, hemlock, dogwoods, rhododendrons (including azaleas), spirea, white and red pine, yews as well as roses and bluegrass and fescue lawns.
Initial salt damage is caused by the burning effect on the foliage of evergreens. But later on salt causes plant injury if it accumulates to excessive amounts in soil near the root system. This frequently happens when salt-laden snow is plowed off streets, sidewalks and walkways and onto the adjacent landscape.
Anyone who has tried to get wet table salt out of a salt shaker (like out here in August) knows that salt readily absorbs water. Rock salt exhibits the same property in the soil and it absorbs much of the water that would normally be available to roots. Thus, even though soil moisture is plentiful, high amounts of salt can result in a drought-like environment for plants as the soil warms in the spring. In addition, when salt dissolves in water, sodium and chloride ions separate and the chloride ions are readily absorbed by the roots. These ions are carried through the sap stream to actively growing portions of the plant such as leaf margins and shoot tips where they accumulate to toxic levels. What we then see are the characteristically scorched or “burned” margins.
The symptoms of salt damage that you may only notice later in the spring or much later may appear similar to those problems associated with drought or root injury. Stunted, yellow foliage, premature autumn leaf coloration, death of leaf margins (scorch) and twig dieback are common. When conifers are injured by winter deposits of salt spray, the affected foliage turns yellow or brown in early spring. If spray is the primary means of salt deposit, discolored needles are soon masked by the new year’s growth. However, if salt is also excessive in the soil, the new needles may die as chloride ions accumulate in them. If this happens for several years in a row, it can be fatal to the tree. In cases of severe or accidental salt damage to the soil, horticultural gypsum can be added to possibly neutralize the harm.
Be careful, and keep growing.
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