Don't laugh. What is sew-in interfacing and why do I need it? I'm making a dress for the baby - am I reading it right that I'd not need to hem it? It just shows to sew on the interfacing and then turn right side out and you're done.

Can someone help a newbie?

It sounds to me that they intend the interfacing to act like a facing...if you sew it right sides together and then turn it out, then the raw edges will be enclosed and you don't need to hem. Pressing should be sufficient to make it look nice.

Ok, that makes sense - I guess I'll go get some today, I hate hemming so this is a great pattern for me! LOL