We have well water which is fairly high in iron.
Should I use this water "right out of the well",
or can I use the tap water, which has been softened
and run through a charcoal filter?
If both options are really bad...is it worth it to
try to collect rainwater?
Thank you very much!

The water that has been through a charcoal filter should be fine, unless the softening uses salt - that could be damaging. The water with iron won't do too much harm, but may stain the leaves if it gets on them too often. Derek