If you find yourself short of fabric when hemming a garment, you can create a false hem. This involves attaching a separate strip of material, as a facing, to add length. This extra material is not visible, since it is part of the material that is turned up under the hem. The lining is often a good choice for false hem facing, but any lightweight fabric will work. Using this technique, It is possible to add more than an inch to a garment's length.
Remove the existing hem stitches by clipping them with a seam cutter.
Press the original hem crease flat. Iron the wrong side first and then the right side of the fabric. Use a soft brush to remove any remaining stitch remnants.
Cut a new facing for the hem. Make this piece of fabric equal to the original hem in height plus 1/4 inch, as a seam allowance. Measure the circumference of the garment's hem and add 3 inches for the length of the facing.
Match the facing border to the hem edge. Pin it in position.
Sew with the right sides together to form a 1/4-inch seam allowance. Start your stitching at a side seam.
Finish the end of the facing by turning it under when you come to the end of the seam. Some of the extra fabric added to the circumference will remain when you arrive back at the side seam. Leave 1 inch. Then tuck this portion under and stitch it into the seam line to create a finished edge on the facing.
Trim the seam with scissors to 1/8 inch of the stitches.
Turn the whole facing to the inside of the garment and press the new seam flat.
Pin the facing to the garment in this permanent turned-up position.
Stitch to create a new hem. Use a loose slip stitch to make a line of hemming stitches that are barely visible from the right side.
You can use a contrasting fabric to make the hem facing a creative element.