if you take them to a professional, he or she could hem them on a blindstitch machine and that stitch stretches. If the business had a coverstitch machine, that could be done also.

Do you have a serger? Your instruction book may describe a way to hem and kind-of coverstitch the edge. (Usually something like a three thread overcast and needle tension set on zero or one)

The best results I've had with a domestic machine was done by inserting a double needle and topstitching with that. The bobbin thread will look like sort of a zig-zag on the underside. It's tidy and will allow some stretch in the hem with less thread breaking.

Hemming knits is very easy to do.

I first run around the edge in a multiple step zigzag to help stabilize the edge. Then I hem them using the blind stitch.
See below.

Here is a link that might be useful: blind hem stitch

Here's what I would do:

I'd get out the widest twin needle I had, and fold the pants over *without* cutting them.

Then I'd topstitch around the hem, and trim close to the stitching on the back side.

The zigzag of the bobbin thread makes double-needle stitching stretchy, and the double line looks neat from the front (lots of manufacturers use double needle topstitching on knits).

And by not cutting until later, I don't have to wrestle with the curl of the knit fabric while I'm stitching.

Talley, I only have a small Singer and have not had the experience of using a twin needle--in fact I am not sure that I even have one. If I don't, what then? Thanks all for your help. Barb

I've done the double needles but usually for hemming t-shirt bottoms or sleeves, but not pants hemming, though I suppose you could, because it will leave the threads showing. I usually prefer a blind hem on pants.

Below is a video on how to do it. It's a needle you buy and you need to use 2 threads on the top, threading each needle with one thread.

Here is a link that might be useful: Double needle tips