Stitching in the ditch is a quilting technique, but it’s a good one to know for other sewing projects as well. I don’t use it a ton, but occasionally when I’m making curtains or am looking to make something less “puffy” it works well.
To do this stitch, prepare your seam the same way we’ve done for the past two weeks…sew it with your recommended seam allowances and press them outwards. As you can see in the picture above, I actually used last week’s top stitching sample to show this stitch.
Make sure that whatever lining or backing will be attached to your front piece is attached and lined up properly before beginning. (If there isn’t going to be a lining or backing there isn’t much point to this stitch). Using the center hash on your sewing foot as a guide, slowly stitch down the center of your seam, going through your upper fabrics and your backing/lining below.
Obviously when you do this on your fabric you’ll want to match your thread to what you’re sewing (and match your bobbin to your lining/backing) but this gives you an idea of how well it disappears, even with a blatantly wrong thread color.
As always, if you have any questions or comments, don’t hesitate to comment, email me, find me on Twitter or stop by on Facebook!
Especially Creative Broad 
I don’t think stitching in the ditch would necessarily be categorized as a quilting technique that is also used for other projects. The technique is used extensively in garment sewing and may well have originated there.
Huh, I’ve always heard of it being something that came from the quilting world, but you may be right Snarky!