Official winter is close to a week away, but we have already suffered the blast of the Arctic! And although it’s an important topic, our listeners generally don’t ask about plant- and surface-safe ice melting products and techniques until we’re well into the season of slip and fall.
For instance, it wasn’t until the second week of January 2013 that John in Kensington was the first listener of that snowy season to ask about de-icers. He wrote: “I have a stamped concrete walkway surrounded by mature foundation plants. I’ve read not to use magnesium chloride, calcium chloride or potassium chloride because they could degrade the cement …”
Good news, John—concrete is not cement. (Check out the geeky details.) Concrete is mostly crushed-up stone and sand (the ‘aggregate’) held together with small amounts of cement. More importantly, my stamped concrete patio (yes, I have one too; they’re great!) has not been harmed by use of any of the alternative de-icers you name—and neither have the precious plants nearby.
(My personal favorite of the three is calcium chloride; it melts ice at very low temperatures and seem to be the most gentle on plants. It’s also widely available. I prefer to buy it in big plastic shaker jugs; it’s more expensive than the same amount of material in 25-pound bags, but resists moisture much better in storage.)
But rock salt does not rock!
Just be sure to avoid products that contain sodium chloride — rock salt — whose presence is often hidden behind the letters NACL. Some of the so-called ’alternatives’ out there are actually rock salt wearing lipstick and heels; so read the label carefully: “NACL” as an ingredient means that it’s probably mostly rock salt.)
I repeat: Do not use rock salt to de-ice areas that are near, or will drain into, lawns, shrubs, trees or other plantings. The salty soil that results can limit the ability of those plants to take up water and nutrients, and is often the real cause of “winter-killed” grass in the spring.
Best practices for plant-safe de-icing
- Always shovel any snow away first, then use an alternative de-icer to prevent re-freezing afterwards.
- Use very small amounts of de-icer; just a light sprinkling of one of the alternatives will melt your ice and keep it melted. (In fact, if you do it right, you’ll use so little material that it wipes out the price difference between the alternatives and rock salt.)
- If you know we’re going to get an icy rain (or rainy ice), treat the walkway before the weather event begins and no ice will ever form. If heavy snow is predicted, let it snow—and then get rid of the snow before you apply de-icer to the shoveled surface.
- Don’t shovel any snow that may have been in contact with rock salt or road salt onto lawns or other plants.
- But do shovel clean snow onto your lawn and around your shrubbery. Snow is a great plant insulator, and when it melts it’ll help dilute any salt that did happen to reach your poor plants.
- And if road crew salt keeps hitting the edge of a planting area, toss lots of clean snow there to dilute the salt and protect your plants.
What about kitty litter and ‘play sand’?
John in Kensington asked about alternatives to the alternatives! He wrote: “What about play sand or kitty litter? I don’t have access to the wood ashes that others have recommended.”
I suspect that wood (and more likely, coal) ash was widely used back before bagged de-icing products were widely available. (And when people had lots of coal ashes to get rid of.) It certainly created some grit to help prevent people falling, but is about as messy a choice as you could imagine.
And so is kitty litter. After years of including it in my annual recommendations (because I had read it somewhere), I finally tried kitty litter on my front walk and it made a huge mess: almost as bad as ashes. I practically had to take off my shoes before I got in the house!
But John is right on the money with sand. It’s now being used extensively by road crews on icy highways. It doesn’t melt ice directly, but it provides sure footing—and sand is good for our poor plants; it loosens up the terrible clay soil they’re trapped in. And sand doesn’t have the potential to harm and corrode roadways, cars, surfaces and structures the way salty de-icers can.
Pound sand, not plants!
That’s right—using sand to make your walkways safe doesn’t just protect your plants from chemicals; it has the potential to lighten up your clay soil as well!
The sand experts at Quickrete tell me that you specifically want what’s called “all-purpose” sand; that’s what the highway crews use to make icy surfaces safe. (It’s also the type most often found on the shelves of big home stores.) ‘Play sand’ is a more purified, kid-safe version that de-slipperizes ice just as well.
And my good friend Howard Garrett, who dispenses organic advice down in Texas under the handle “The Dirt Doctor,” says that a product called lava sand is the absolute best choice. It’s gritty enough to provide traction and is sold in big bags at hipper garden centers to be used specifically as a soil-improving amendment! Make your walkways safe and feed your plants—amazing!
Christmas plant countdown!
One week to go! Let’s review:
- Poinsettias are warm-weather plants; don’t expose them to the cold outdoors.
- Those cute little rosemary trees can handle temps down at the freezing mark (bring them inside on nights when temps drop well below freezing). But these little beauties are always sold in a severely root-bound state and must be repotted into larger containers to survive; use compost or a professional potting soil to fill in the gaps in the bottom and sides of the new pot. Water wisely (whenever the pot itself feels light; never when it feels heavy), keep it outside when temps are above freezing, and that ‘tree’ may well survive to grace your garden with its fragrant herbal beauty come spring!
- Blooming amaryllis should be kept in a cool spot to prolong the flowering time. If you want to attempt a re-bloom, clip off the faded flowers but do not remove the green leaves. Feed gently after the flowers fade, give the plant good light and move it outside in the summer. (Then email me in August and ask for further directions.)
- Do not let the water holder of a cut Christmas tree dry out, or needled you will be.
- If you’re going to have a truly live tree, keep it inside for the shortest time possible, in the coolest room possible, and add ice cubes to its water supply. And if you don’t have the planting hole dug for it outside yet — well, God bless you …
