I've been making plenty of circle skirts this past year as I am developing my first pattern which has 2 views, one with a 1/2 circle and another view with a gathered full circle skirt. So I quickly learned different ways to hem them.
Circular hems are sometimes tricky to finish as its rounded shape makes it difficult to fold over and sew, which can result in a warped looking edge.
Therefore the best (in my opinion) and easier way is to make a facing out of a strip of bias cut fabric. You can choose to use the same fabric as your skirt or choose a fabric in a contrasting color or fun print! This adds a special finish to the inside of your garment. I love to use quilting cotton for this as there are so many beautiful designs out there but can often be too busy for making a complete garment out of.
1st, make sure to let your skirt hang on a hanger or dressform for a minimum of 24 hours, if not more to allow the sides that are on the bias to stretch out. After hanging, the hem will need to be trimmed where it has grown. Every fabric type will behave a bit differently, and therefore some may grow more than others.
To make your bias strip you will need to cut strips on a 45 degree angle from the selvedge or straight edges. I usually like to cut my strips out at about 6-7 cm wide. In order to make one long continuous piece, you will need to sew the strips together like so:
Place strips Right Sides (RS) together, one horizontally and the top piece vertically. Overlap them so the ends stick out a bit.
Sew the pieces together starting at one corner and ending at the opposite corner. Make sure to back stich a couple times at the beginning and end of seam.
Trim excess, leaving about a cm Seam Allowance (SA).
Press open Seam
Optional: Before pinning bias strip to the hem, you can "shape" the strip into a more rounded shape with your steamy iron, curving and gently pulling on one side while ironing.
Pin the bias strips right sides (RS) together with the hem of the skirt,. Turn in the short edges, and overlap them then sew ⅜ inch away from edge. Starting at the side seam.
Remove pins and press down the bias strip and under stitch it to the SA ¼ inch away from seam.
Turn skirt inside out then fold and press the raw edge of the bias strip in by ⅜ inch and then fold that in and press to the WS of the skirt.
Pin and sew along the edge of strip, at about ⅛ inch. “Stitch in the ditch” vertically into the side seam to tack down the edges bias strip.