Hold the Salt
Roger Cook’s tips on how to keep slushy salt from killing your lawn
In winter, salty slush from the road sometimes ends up on my lawn and kills the grass. Is there any way to prevent this?
—Sean Donovan, Guelph, Ontario
When salt gets into the soil, grass, shrubs, and trees all suffer. That’s because salt steals moisture and so creates drought-like conditions for the roots, even when the soil is damp.
The best way to prevent salt damage to grass and other plants is to keep salt from getting in the soil in the first place. Consider erecting a temporary burlap or plywood screen to block the slush and spray flung by snowplows, and take care when shoveling or snowblowing to deposit salty snow in a place where it won’t melt into your yard or garden. And if that snow does end up in those places, get rid of it as soon as possible. This is especially important in late winter and early spring, when plants are emerging from dormancy.
Once salt gets in the soil, it’s not easily removed. You can try flushing it away in the spring with daily deep waterings. This strategy works best on soils amended with sand and compost, both of which enhance a soil’s ability to drain. Incorporating gypsum into the soil also helps because it dislodges sodium ions and allows them to be washed away. Have your soil tested first so that you know just how much gypsum to add.
Here’s another approach that may be less of a chore: Instead of growing grass, create beds with salt-tolerant shrubs and perennials in those areas where road salt can’t be avoided. There are a number of such plants, including Rugosa rose (Rosa rugosa), Creeping juniper (Juniperus horizontalis), Fountain grass (Pennisetum alopecuroides), Cheddar pinks (Dianthus gratianopolitanus), and Seaside aster (Erigeron glaucus). And they can survive your long winters, too. Making this small retreat from snowplow splash may be the best way to save your lawn.
Shown: The rock salt used to melt snow is harmful to plants, so keep slush off lawns and garden beds.