Posted: 13/10/2014 at 13:11
Water via a water softener contains salt in some cases. Too much salt is bad for many plants except those who like coastal conditions. I can only assume the advice given too you about water from a dryer is based on the fact man made chemical residues, which adheres to clothes even after rinsing, will be bad for your plants.
The accepted wisdom is to rely on rain water for some plants, if not all. Tap water still contains traces of fluoride in many area's and trace amounts of other chemicals used in treating water supplies.