The rest of the garment is left with the full hem allowance. Catch stitch the garment hem to the interfacing. Steam press the hem to get the desired edge. Another popular technique allows the garment to be lengthened at a later time, if necessary. Catch stitch the hem to the interfacing.
Steam press the hem to get the desired edge.
There are two ways of finishing these vents. Choose the one that works best for you. Either method gives a neat, flat vent. The overlapping side along the vent edge can be stabilized with fusible interfacing. You may choose not to put it in the hem.