Hemming a wedding gown requires special techniques for the special bridal fabrics. Learn to hem netting, pick-up skirts, and skirts with lace edging.
Marking the hem
Begin with the bride wearing all her bridal undergarments, shoes, and the gown. The gown should already fit through the bodice and waist before the hem is marked. The slip should also be hemmed if necessary before the gown hem is marked. Double check to be sure no additional alterations are needed. Fluff the slip; failure to do this may result in a finished hem that is embarrassingly short.
Now have the bride stand on a flat surface, not plush carpeting. Ask her to hold up all layers of the skirt except for the innermost layer. You will mark the hem from inside to outside, one layer at a time. The method of marking depends upon the type of fabric and construction in each layer. All under layers should be hemmed first; then the bride returns for another fitting at which the outer gown is marked. Here are directions for marking and hemming each layer.
Gathered netting ruffle
To hem an under layer which includes a ruffle at the bottom, pin a tuck just above the ruffle. Sew this tuck and the ruffle remains at its original width, providing the fullness it was meant to provide. The finished ruffle should be about 2 inches from the floor so the bride may walk safely and the under layer will not show under the outer edge of gown.
Layers of netting
Layers of flat netting are simply marked with a pin line parallel to the floor and cut along this line. Each successive layer is cut just slightly longer than the layer underneath it, resulting in graduated layers at the hem line.
Pick up skirts consist of many small gathered spots randomly scattered around the skirt. To shorten this type of skirt, pin the pick-ups at the stitching lines, pinching up a bit more fabric than was originally sewn into the pick-up. Small amounts may be shortened by taking in just the pick-ups nearest the bottom. Larger amounts may require that most of the pick-ups be taken in or even that the gown be shortened at the waist (a technique beyond the scope of this article.) The hem of a pick-up skirt is not perfectly straight, but dips slightly between pick-ups.
Take a tuck behind the lace edging, pinning the top points of the edging to the skirt in place where the edging needs to be moved. The bottom points of the lace edging should be about 1 inch from the floor once the top points are pinned in place.
To sew this hem, remove the lace edging carefully with a single-edge razor blade or a surgical-style seam ripper. Pin the lace at the new spot as you go, leaving the excess fabric behind the lace. Once all the edging has been moved to the new spot (cut and overlap lace as needed to fit) stitch in place with small hand stitches and matching thread. Finally, cut the excess fabric from behind the lace edging.
Source: personal experience in sewing and bridal alterations