Q • My tap water has a lot of salt in it, and it is very hard. Will it hurt my plants?
A • Hard water is generally OK for plants. If you have a water-softening unit on your water supply, the treated water contains high levels of salts. Salt can build up to toxic levels, and burn roots, which can manifest itself initially as brown edges on plant leaves.
Have a plumber install a tap in the supply line just before the water goes into the treatment unit. That will allow you to draw untreated water for use with plants. All things considered, the best water for plants is rain water. If you have a way to collect and store it, that would be ideal. Always warm it to room temperature first, before applying it to indoor plants.
Write to Chip Tynan of the Missouri Botanical Garden at email@example.com or Horticultural Answer Service, 4344 Shaw Boulevard, St. Louis, 63110.