What kind of soil and/or potting mix should I use when repotting a small Norfolk Pine?
Use a good quality potting soil that is well draining.
Make sure the plant actually needs repotting, before going to the trouble.
They prefer to be root bound and actually can go 2 to 4 years before repotting.
If you see roots on the top soil surface or growing out of the drainage holes, this indicates the need to repot.
Make sure you only increase the pot size by 2". If it is in an 8" pot, choose a 10" pot.