How to Prevent, Repair Rock Salt Damage on Lawns
BY JILL RAMONE | NOVEMBER 21ST, 2019 | COLD CLIMATE, HOME & GARDEN, LANDSCAPING, LAWN CARE
The debate over rock salt is a slippery slope. More than 25 million metric tons of rock salt are dumped onto roads, sidewalks, and driveways every year to de-ice them. While these de-icing salts make life safer for motorists and pedestrians, they have the unintended consequence of damaging lawns. Most of the time, salt damage is not apparent until spring, when snowmelt and warming temperatures reveal the dead grass.
Protect and Repair Your Lawn from Salt Damage
10 Ways to Reduce, Repair Salt Damage on Grass
If you live on a major roadway where crews use salt as a road de-icer, consider a little preventive and remedial lawn care to safeguard your lawn.
- Fencing: Install silt or snow fencing around your yard to protect your lawn from salt overspray.
- Cover: Use plastic or burlap sheets to cover the grass, flower beds, and areas around trees.
- Shovel smart: Shovel snow often and avoid piling any treated snow around plants or on the lawn.
- De-icing salt alternatives: Apply kitty litter, ashes, sawdust, or sand instead of rock salt to driveways and sidewalks.
- Dilute the salt: Reduce the amount of salt you use to de-ice by cutting it with six parts sand to one part salt.
- Sodium chloride alternatives: Magnesium chloride, calcium chloride, and potassium chloride are less damaging.
- Flush the yard: As soon as the snow melts in the spring, give your lawn a deep, daily soaking for a week to flush rock salts.
- Treat with gypsum: Spread pelletized gypsum soil conditioner to reverse the damage to the soil.
- Plant choices: Check for salt tolerance when buying grass or garden plants.
- Re-seed or overseed: If the grass has salt buildup, overseeding can ensure some healthy growth.
Why Does Salt Damage Grass?
When rock salt is applied to icy surfaces, it melts the ice and then runs off or is sprayed by the tires of cars driving through the slush. That overspray can travel up to 150 feet, which means even if your yard isn’t directly affected, some mist may still reach your yard. Salt spray can cause injury to plant buds, leaves, and stems.
Salt draws moisture out of leaves, leaving them brown and dry. It also pulls moisture out of the soil, causes soil compaction, and exposes grass roots to chlorides. When chlorides build up to a toxic level, plants lose the ability to produce chlorophyll and eventually die.
How Does Salt Damage Hardscapes?
Rock salt has a corrosive effect on hard surfaces, often leaving white spots on natural stone walkways and patios. Concrete that isn’t sealed is porous and will soak up the briny water left behind from a de-icing treatment. That absorbed water will refreeze when the temperature dips below freezing, causing expansion. This process will eventually cause chipping, cracks, and flaking in concrete structures. The least expensive de-icing salts tend to be the most corrosive. Pricier de-icing agents are less harmful to grass and less corrosive to concrete and stone. Even if you use a cheaper, more corrosive de-icer, you can cut it with sand to reduce the volume of harsh chemicals.
How Long Does Salt Last in the Soil?
Salt remains in the soil for years, and it accumulates over time until it creates an environment where grass can no longer thrive. Salt is leached out by rainfall, but it can take a while for this process to be complete. Speeding this process by irrigating deeply once the weather warms up will help. But the best solution is to avoid the accumulation of salt in the soil in the first place.
Genevieve Schmidt, owner of Genevieve Schmidt Landscape Design and Fine Maintenance in Humboldt County on California’s northern coast, recommends using calcium or magnesium acetates rather than chlorides to de-ice areas around yards and landscapes. She cautions, “When you see dieback and browning or yellowing of leaves, it’s evident there’s been salt damage. If you suspect salt has leached into your landscaping, it’s wise to rinse plants and soil with water as soon as the snow melts. Apply 2 inches of water over a two- to three-hour period, then repeat a few days later.”
Repairing a Salt-Damaged Lawn
There is little point in reseeding or overseeding a lawn that has a high level of salt buildup. Without flushing out the salt beforehand, the new grass will absorb the chlorides in the soil and eventually suffer the same fate as the grass you’re replacing. Once you’ve adequately flushed salt out of your lawn in the spring, take your time to reseed your lawn the right way. While salt damage in your yard is nothing to shrug off, it also isn’t the end of the world. With a little foresight and prevention, you can protect your lawn and treat the damage before it’s irreversible.
Main image credit: Michael Pereckas, CC by 2.0