Salt is good, right? We say someone is “salt of the earth” if they are virtuous. Salt is a valuable commodity, sometimes used for barter or as money. Roman soldiers received part of their salary – salarium – in salt. A worthless soldier (or slave) wasn't "worth his salt." But, salt can be a bad thing. Just ask any coastal gardener. Storm surges from hurricanes - even minor flooding - increase salt content in the soil.
I know it’s true. My aunt, whom I was visiting recently, commented that she’s had mighty poor results in her garden since the storm surge of Hurricane Matthew in 2016. She lives beside a tidal creek meandering through a salt marsh. Her soil is naturally poor, but the inundation made matters worse.
Why is that so?
According to Guy Sela, CEO of SMART! Fertilizer Management software and an international expert in plant nutrition and irrigation, wrote, “Salinity can affect plant growth in several ways, directly and indirectly.” Direct soil salinity damages plants by decreasing their water uptake. “… the plant has to use more energy to absorb water. Under extreme salinity conditions, plants may be unable to absorb water and will wilt, even when the surrounding soil is saturated.”
He continued, “When a plant absorbs water containing ions of harmful salts, … visual symptoms might appear, such as stunted plant growth, small leaves, marginal necrosis of leaves or fruit distortions.”
Soil salinity can also interfere with absorption of essential nutrients. “An imbalance in the salts content may result in a competition between elements. This condition is called ‘antagonism’, i.e. an excess of one ion limits the uptake of another ion.”
Sodium can also have an effect on soil structure, reducing the ability of water to infiltrate when wet. When dry, it becomes hard, cracks, and may result in root damage.
He notes, “salinity by itself actually improves soil structure”, but “salinity cannot be increased without affecting plants growth.” In other words, a little salt of the earth is a good thing, but too much is not.
What can you do if a storm surge affects your place? Not much, though you might consider choosing salt-tolerant plants in the future.