You could cheat with some press-a-seam tape to hem first, sew your line, then cut off the bulky. Or press your hem without tape, pin it well, sew, trim.

I use the method , how to hem jeans with original hem , from sew simple home. Works for me. Easy peasy.

Do you have a sewing machine? Or will you be doing it by hand?

On my machine, I have an overcast stitch that gives support to the hem. I fold the pant leg up where I want the finished length to be and then press using a clapper (a piece of wood that you put over the crease as soon as you finish pressing and hold it there for 10 seconds or so...creates an incredibly sharp crease). I then trim the rest away leaving about 1 1/4" hem. Use the overcast stitch around the raw edge and then either hem on the machine or by hand.

I don't recommend using the iron on tape as it won't stretch. If you stretch the fabric at all, it will strain the fused part and eventually may come undone.

She talks about overcast stitch on knits here:

https://www.youtube.com/watch?v=Kd8VVCIpzhY

Here she shows how to blind hem using a machine:

https://www.youtube.com/watch?v=6Q4oaueMvKc

Sometimes when I have to hem a knit that keeps curling up I spray it with spray starch and iron to stiffen it. The starch easily washes out afterwards.

The pants did not shrink at all in the wash, so maybe it's the poly in them. I'll allow for shrinkage over multiple washings/dryings over time when I hem them.

Thank you, everyone! So helpful, especially the videos. I never thought about the hemming needing to stretch as the foot goes through. I will get out my old Singer manual. I might have blind hem as well as overstitch disks which change out (far from the newer machines).

I would wash them first too and then pin up the hem where I think it should be and look in a mirror to make sure they are not too short. I press that hemline before I do anything. Then I would cut off the hem allowance to about one and a half inches and overcast the edge. If you don't know how to blind hem on the machine, you could stitch them by hand a this point or use a simple machine stitch that isn't too tight.

socks, even if you don't have overcast stitch, you could use a basic zig zag which will still help support the hem.

Looks like some good (better) advice. I was just going to suggest washing then in hot water and putting them in in the dryer for a spin. Seems to shorten/shrink lots of things!

They have been washed once, but I'll wash once more, especially since the back hems have been dragging around on the ground all day! I won't use hot because of the poly.

I have 2 disks: One is a "blindstitch" and the other is "overedge stretch stitch." Why couldn't I just sew turn them up and sew with the overedge stretch and then cut off the excess?

socks you certainly can do that if you don't mind seeing the stitching on the front of the pant.

Mark where you want the cut line to be and overcast BEFORE you cut off the excess. The spray starch tip is a good one, too.

I'll bet one of those variations of tear-away stabilizers or interfacings would work well. Can't recommend one because I haven't done much sewing in years. There are so many new products now to make tasks much easier than back when I used to sew a lot.

Mission accomplished. Not professional, but good enough. Appreciate all the help.

Good for you! Next time, it will be easier.