Top Stitching. Edge Stitching. Understitching. Stitch in the Ditch

Understitching is a row of stitching on the facing or under layer that keeps the facing, under layer, or seam edge from rolling to the outside of the garment. When understitching, you press the facing away from the garment and position all the layers of the seam allowance to the facing side. On the correct side of the facing, you machine stitch close to the seam edge. While stitching, gently pull the facing and the garment sections on both sides of the stitch line to help make both pieces lay flat.
Stitching in the ditch is sewing in the ridge of a previously stitched seam, on the correct side of the garment. Because it is sewn into the ridge of a seam, it is an inconspicuous stitch. It is used to complete waistbands, cuffs, collars, and French bias binding, when you don't want the stitching to be obvious. You use a regular stitch length and thread, whose color matches the fa...