|As I was finishing up a top in a space-dyed knit today I realized that this tip has never been brought up here on PR. Did you know that a blindstitch machine (such as the Tac-Sew T-500) makes a great, stretchy hem on knits? I know we always focus on using a zigzag, double-needle or coverstitch but sometimes a particular fabric needs an invisible hem. Doing it by hand often results in thread breakage and so isn't too practical. I use a fine needle, serger thread and set the machine to no-skip.
My friend Sharon even uses her blindstitch to finish necklines on knits for a neat, invisible finish without a bulky facing.
Additionally, I know that some conventional machines have a stretch blind hem (done with two different widths of zigzag) which is also great to use if you don't happen to have a blindstitch machine.