Absolutely the unsoftened outside water. Don't use softened water on ANY plants. You can easily get an inexpensive TDS meter online, or at a hydroponics store (I suspect easier to find where I live than where you are) But for just a few orchids, don't stress on it. It takes very little for it to manage any acidity with fertilizer. A cup a gallon should be fine. (that's 1:16, so whatever the TDS is to start with, you end up with 1/16th as much, then you add in your fertilizer and go for it)
|