The Aftermath of Hurricane Helene and Soil Salinity Issues

By Stephen Douglas Robinson

Commercial Agent, Pinellas County Extension Service

The Storm Surge of Hurricane Helene in Pinellas County, Florida reached a confirmed height of 7.00 feet above the average high tide elevation, not including wave height.  The Gulf of Mexico and waters of Tampa Bay can attain a total chloride content of (35,000-38,000) parts per million or (35 to 38) parts per thousand.  The (35,000-38,000) parts per million chloride concentration is capable of desiccating almost all native and introduced trees and shrubs within 48-72 hours.  The high concentrations of chlorides quickly remove the internal fresh water from plants by simple (diffusion and or osmosis).  The concentration of chlorides, in salt-water flooded soils and sediment will increase in concentration as the soil medium becomes drier.  Following a saltwater flooding event, it is ideal to receive freshwater input from rainfall.  Rainfall will help to reduce soil dryness while also reducing the total chloride content of the soil through natural dilution processes.

If you are concerned the plants and soils within a saltwater flooded area, the Pinellas County Extension Service can analyze soils for total chlorides for a $10.00 fee.  It would be advisable to avoid new plantings in an area(s) that have received saltwater flooding from Hurricane Helene until the soil show signs of natural plant recruitment, such as weed seed germination of salt-water intolerant plant species.  It would be highly prudent to avoid fertilization of plantings at this time if a planted area was flooded by saltwater from Hurricane Hellene’s storm surge.  Be especially careful when trimming trees and large shrubs in the vicinity of power lines of any kind.  Never cut a branch that has any part that is within 10-feet of a powerline.  To repeat, be sure that any branch that you are considering cutting has (no part within 10-feet) of any powerline.

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