The ravages of winter in the northern United States present many challenges for lawns, plants and trees. Freezing temperatures, heavy snow, wind, and ice can all affect the beauty of your landscaping when temperatures finally rise and spring officially begins.
But one of the most damaging aspects of winter for your landscaping doesn’t come from Mother Nature. It comes from winter salt.
From municipal snow plows to our own efforts to clear away the snow and ice, our landscapes are subjected to excess salt that can damage precious plants, discolor our lawns and even crack and discolor pavers, concrete walkways and patios.
Fortunately, there are ways to prevent and minimize the damage that winter salt can cause. Here are some pro tips for preventing winter salt from spoiling your beautiful landscaping this winter and for many winters to come.
Types of Winter Salt
The three most common types of winter salt used for snow melting and de-icing are:
Also known as rock salt or sodium chloride, NaCl is the most widely available and cost effective option to melt snow and ice on roads, driveways and sidewalks. It is also the most common material used by municipalities and contractors. Unfortunately, excess rock salt can be damaging to lawns and plants. Frequent thawing and re-freezing caused by rock salt can also damage concrete walkways and pavers. Rock salt is most effective when outdoor temperatures range between 15 to 20 degrees Fahrenheit.
Also known as calcium chloride, CaCL2 is the most common alternative to rock salt, available at hardware stores. This option is safer for lawns and plants, but will damage hardscaping such as concrete patios, pavers and walkways. Calcium chloride is most effective when outdoor temperatures dip below 0 degrees Fahrenheit.
Also known as magnesium chloride, this de-icing product can cut through ice at sub-zero temperatures without damaging lawns. It is more expensive than either rock salt or calcium chloride and also is very destructive to concrete and pavers.
How Winter Salt Damages Lawns, Plants & Trees
When excess salt penetrates the soil, plants absorb the sodium from the salt through the roots. Because salt attracts water, the rock salt in the soil robs plant roots of essential water, causing dehydration.
The chloride in salt is also absorbed by plants, traveling through the roots to plant leaves and stems, where it accumulates and interferes with chlorophyll production and the process of photosynthesis. This stunts plant growth and can keep plants from producing leaves or flowers.
Evidence of salt damage is most visible on evergreen trees and plants because they retain their needles throughout the seasons. Salt-damaged evergreen trees or plants exhibit brown needles. The brown color starts at the tip of the needles and eventually travels to the needle’s base.
Salt damage to deciduous plants and trees might not be noticeable until spring, when plants fail to produce leaves or don’t bud properly due to salt damage. Salt-damaged grass is often brown and patchy.
Salt can also damage lawns, plants, shrubs or trees through indirect exposure. Passing vehicles and snow blowers can spray accumulated salt onto plants, which damages the leaves, buds and small shoots. This salt spray can also reduce a plant’s cold hardiness, making it much more prone to damage from freezing temperatures.
How Salt Damages Concrete / Pavers & Hardscaping
While concrete and other hardscaping products appear solid, they are actually very porous, causing them to absorb water. Rock salt works by lowering the freezing point of water from 32 degrees Fahrenheit to 25 degrees, promoting melting between 25 degrees Fahrenheit and above.
Salt naturally attracts additional water. This salty water then seeps into small cracks and crevices in concrete, pavers or other porous hardscaping. The damage occurs when the water refreezes when temperatures drop below 25 degrees. This causes the water to expand to form ice, widening cracks and crevices. If thawing and refreezing occur several times, damage is much more likely.
Other de-icing products such as calcium chloride and magnesium chloride can also damage concrete if they are left standing on the surface after the ice has melted and the water has drained away.
Preventing Winter Salt Damage
Use Only What You Need
When salting or de-icing your driveway or sidewalks, use only as much salt or de-icing as you need and only apply it where you need it most. This will minimize the impact on your lawn, garden plants, trees and hardscaping. Pay particular attention to areas of your walkway or driveway that are close to your lawn or flower beds. Try to avoid spreading winter salt to these areas.
Don’t Allow Salt or De-Icing Products to Stand on Pavers or Concrete Surfaces
After the ice has melted, be sure to remove any leftover salt or de-icing products promptly to prevent damage to concrete or pavers. If it’s too cold to use a hose to wash it away, sweep up the excess salt as soon as you can. Don’t spray or sweep salt or de-icing products into your flower beds or onto your lawn. Instead, dispose of it in the trash.
Ensure Walkways and Driveways are Properly Graded
The grade or incline on your sidewalk or driveway determines where excess water flows. Make sure that your sidewalks and driveway are graded to encourage water to flow away from your plants. Also pay attention to the grade of any hardscaping before adding new plants. Avoid planting in areas where water and salt runoff will affect those plants.
Add a Screen or Snow Fence
Salt spray from passing cars and snow plows can travel up to 150 feet. If you live along a busy street where vehicles and snow plows frequently drive by, add a burlap screen or snow fence along the edge of your lawn or garden to catch salt spray before it reaches your grass or flower beds.
Use Alternative Products for De-icing and Traction
While not as effective as rock salt or de-icing products, using kitty litter or sand can help melt ice and provide traction without damaging your lawn or plants. Kitty litter and sand are also safe for use on concrete, pavers and driveways.
Minimize Salt Damage with Water
When temperatures rise above freezing, it’s helpful to rinse off plants that have been exposed to salt. This helps dilute the salt, minimizing damage to your plants and lawn.
Treating Salt-Damaged Plants
Despite your best efforts to prevent salt damage to your grass or plants, it won’t always be possible to prevent salt damage altogether.
Luckily, you can reverse salt damage to grass, plants and trees by applying gypsum and water.
Gypsum is a naturally occurring mineral made up of calcium and sulfate that is widely used as a crop fertilizer, soil amendment and soil conditioner. When applied to soil that has absorbed excess salt, the calcium sulfate replaces the salt with calcium and sulfur, helping to heal grass and plants, while also providing soil aeration for improved air and water penetration. Gypsum is gentle and safe to use around people, pets, and plants.
You can apply pelletized or granulated gypsum to lawns with a lawn spreader. Simply apply a thin layer over the affected area, then water thoroughly. Gypsum can also be applied directly to the soil of affected plants, shrubs or trees. Follow the package directions for guidelines.
While winter salt is a part of every winter season in the northern U.S., you don’t need to let it ruin your landscaping. Just being more aware of the type of winter salt you apply and how much you use, removing excess salt promptly and preventing salt spray and run-off can greatly improve the odds that your landscaping survives the winter just as well as you do.
If you do find salt damage during the spring thaw or want to cultivate beautiful flowers or a lush, green lawn this spring, you can count on USA Gypsum for high-quality gypsum products made from recycled gypsum in Lancaster County, PA.