Water Softener and Plants
Name: David W.
When using an ordinary water softening system, utilizing salt pellets,
will there be any detrimental effect on plants, i.e., house plants or flower beds if
the softened water is used to water them? Also, would using potassium chloride be a
Yes, water softeners can be a problem.
The following should be helpful:
Anthony Brach, Ph.D
I do not see any reason why softened water should cause a problem, the level of
sodium replacing the Mg, Ca, Fe etc. ions should not be too extreme. The plants may
even prefer a lower sulfide level if that is a problem. Using KCl instead of NaCl is
going to be a lot more expensive. A balanced liquid fertilizer would compensate for
any of the deficiencies also. Perhaps your question should be directed to a florist,
or Department of Agriculture Extension agent. I am sure studies have done on this question.
Some new thoughts. It may be desirable to let water stand overnight so that any residual
hypochlorite will decompose. Some plants could be adversely affected by that although the
soil may decomposed the hypochlorite before it is taken up by the plant. Also pH is an
important factor for some plants. Dissolved CO2 usually makes tap water a little on the
acid side, but for most plants that would be a short term issue since the soil will buffer
small amounts of excess acid or base. Of course for hydroponic gardening (no soil) things
have to be controlled more closely.
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Update: June 2012