The easiest way to hem a full slip is by creating a tuck near the bottom. Even when the result is a deep tuck it will not ruin the look of the slip. The extra weight at the hem makes the slip hang better.
My reason for preferring to make a tuck is because my sewing machine only has very basic stitches. There are few stitches whether multi-zigzag or blind hemming that work well with the delicate, stretchy nylon of the slips I purchase.
I do not recommend cutting away the extra length unless you do have those stretch stitches or a merrow machine to finish the edges. When the slip has hemline lace you could use the stretch stitches by overlaying the lace on the right side of the slip, about 1/8 to 1/4″ above the new hemline. If you do not have such stitches and prefer to hand sew here is one way to do it.
- From 1/8 to 1/4″ above the hemline lace on the right side, measure up the depth of the amount needed to raise the hemline. Mark with white, clay chalk.
- Pick up along the 1/8 to 1/4″ line above the hemline lace and bring up to the chalk marked line.
- Use fine, long silk pins to pin the hem in place.
- Thread a long, fine hand sewing needle with a single strand of cotton basting thread conditioned by passing through a dryer strip. I find a #10 sharp works well. Experiment to find the best needle for your own hemming.
- Baste the hem in place along the folded line. Remove the pins.
- Pass a long strand of poly-cotton sewing thread through beeswax to coat and prevent tangling. Use it as a single strand with a the same sharp, long hand sewing needled you used in Step 4.
- Use a very tiny running stitch all around the tuck. This line should be about 1/8″ down from the tuck.
- Make a second line of tiny running stitches about 1/4-3/4″ below the first line of stitches.
- The running stitch should not be too tight to prevent puckering. If you hand wash and line dry the slip the stitches remain stable and will not break.
- They hold up to machine washing, too, if the slip is washed in a lingerie bag during a delicate cycle.