Salt can leave a bad taste in lawns and gardens
Salt in the soil can be deadly for lawns, trees and gardens, robbing plants of their ability to absorb water. Salt-tolerant varieties are available, however, and ground laden with soluble toxins can be flushed clean to depths below the root zone.
Regular soil testing is the best way to determine salt levels, said Richard Koenig, associate dean and director of Washington State University Extension.
"The problem is common in the Desert Southwest (with irrigation buildups), along roads cleared with de-icers and near oceans, where you get wind-blown sea spray," he said.
Salinization frequently appears as white-crusted soil on the ground's surface or stunted vegetation, particularly in low-lying areas.
"Another characteristic symptom is brown and brittle plants," Koenig said. "People often refer to (soil) salinity as 'chemical drought'."
Anyone who has tried to sprinkle salt from a wet shaker knows how readily salt stores water, said Leonard Perry, an extension professor with the University of Vermont.
"Rock salt exhibits the same property in the soil, and absorbs much of the water that normally would be available to roots," Perry said. "That's especially a problem in the spring, when plants are coming out of dormancy and their roots are the most active. Salt competes with plants for that water."
Saline soils cannot be reclaimed with chemical amendments, conditioners or fertilizers, according to horticulturists with Colorado State University Extension.
But there are methods for reducing or eliminating salinization in the root zone. These include:
— Detoxifying the soil by flushing. "If you have a way to wash the soil using excess water that is not high in salt, then you can leach them down deeper into the soil," Koenig said.
— Improving drainage. Mulching to prevent evaporation and retain water in the soil also helps. Hose salt spray and pollutants off plants and lawns after heavy storms.
— Using raised beds filled with fresh soil that provides some control over salinity, pH and compaction. "That elevates your soil and lets you leach it out of the beds," Koenig said.
— Adding windbreaks — snow fences, hedges and trees — deflects sea spray.
— Removing and replacing soil covered with road salts. "But unless you can replace the cause of the problem, like moving plant sites farther from roadways, the problem will persist," Koenig said.
— Growing plants that tolerate soil salinity. "Some plants simply grow better than others in salt," Perry said. "If salt concentrations are heavy, going from perennials to annuals might help."
Plants that are particularly salt-sensitive include carrots, onions, strawberries, beans, cabbage and most tree fruits. Salt-tolerant plants include asparagus, Rosa rugosa (beach roses), sumac, prickly pear cactus, columbines and daylilies. Beets, squash, zucchini, chrysanthemums and many evergreens are moderately tolerant, meaning they can survive brief storm surges but should be screened from persistent salt spray.
"Lawns usually aren't as much of an issue, but you will see some browning and damage near roads," Perry said. "That's where barriers help."
Look to native plants as salt-tolerant indicators when doing any seaside or roadside landscaping.
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Online:
For more about managing saline soils, see this Colorado State University Extension fact sheet:
http://www.ext.colostate.edu/pubs/crops/00503.html
You can contact Dean Fosdick at deanfosdick(at)netscape.net
