Staystitching explained: when, where and how

Staystitching is a row of ordinary machine stitches, sewn through a single layer of fabric about 3 mm (1/8 in) inside the seam line, as soon as a piece is cut and before anything else is done to it. It holds curved and bias edges to their cut size while you handle the piece, so necklines, armholes, curved waistlines and the top of a circle skirt do not stretch out of shape before they are sewn. Sew it with a regular 2.5 mm stitch, in the direction the pattern shows (usually from the wide part toward the narrow, or from the shoulder toward the center), and leave it in: it ends up inside the seam allowance.

What does staystitching do?

Any edge that crosses the fabric at an angle to the grain is partly on the bias, and bias stretches. A round neckline, an armhole, the waist of an A-line skirt and the hip curve of a yoke are all cut across the grain, and each is handled a dozen times between the cutting table and its seam: picked up, pinned, turned over, tried on. Every handling pulls it a little longer.

By the time you sew the neckline facing on, a stretched neckline can be 1 to 2 cm (3/8 to 3/4 in) bigger than the facing, and the result is a neckline that gapes or ripples. A line of staystitching locks the threads at their cut length. The stitching takes the pull instead of the fabric.

Where do you staystitch?

• Necklines, front and back, on every woven garment: the most common place and the one that matters most.
• Armholes on sleeveless garments and on anything cut from a loose or drapey fabric.
• Curved waistlines: the top of an A-line or circle skirt, the waist edge of a bodice that curves, the top of a yoke.
• Shoulder seams and any seam that runs diagonally on a very loosely woven or bias-heavy fabric such as linen gauze or viscose challis.
• Any edge the pattern marks for it. Patterns that say "staystitch" usually mark the direction with arrows.

You do not staystitch straight-grain edges such as a side seam or a center back, hems (they are supposed to settle), or knit fabrics, where the stretch is wanted and a line of straight stitching would break when the neckline stretches over the head. On knits, a neckband or a strip of clear elastic does the holding.

What do you need?

• The piece, cut and still flat on the table.
• Regular sewing thread in the bobbin and on top; the color hardly matters, because the stitching will be covered, but matching thread is safest on light fabric.
• A 2.5 mm straight stitch (the stitch length you use for the garment).
• The standard presser foot and the seam allowance of your pattern. With a 1.5 cm (5/8 in) allowance, staystitch at 1.2 cm (1/2 in) from the raw edge; with a 1 cm (3/8 in) allowance, at 7 mm (a little over 1/4 in).

How do you staystitch step by step?

1. Staystitch straight after cutting, before transferring markings takes you across the piece, and before the piece sits in a pile overnight. If it has already been handled a lot, lay the pattern piece back on top and check the edge against it first.
2. Set the machine to a 2.5 mm straight stitch and normal tension. No backstitching is needed at the ends: the stitching is inside the allowance and will be crossed by the seam.
3. Place the piece under the foot, right side up, a single layer, with the raw edge aligned to the mark for 1.2 cm (1/2 in) on the needle plate, or whichever line puts the stitching 3 mm (1/8 in) inside the seam line.
4. Sew in the direction the pattern shows. The rule is "with the grain": from the wide part of the piece toward the narrow, which on a front neckline means from each shoulder down to the center front, in two passes that meet or overlap at the center. On an armhole, from the shoulder down to the side seam. On a skirt waist, from the side seams toward the center. Stroking a cat from head to tail smooths the fur; sewing with the grain smooths the threads the same way.
5. Let the feed dogs do the moving. Do not pull the fabric from behind or hold it back in front; either one stretches the very edge you are trying to hold. Guide it lightly with your fingertips.
6. Check the edge against the pattern piece afterward. If the edge has grown despite everything, pull up the bobbin thread of the staystitching gently every few centimeters until the edge matches the pattern, then press lightly. This is the one time staystitching also acts as an ease stitch.
7. Leave it in. It is inside the seam allowance and disappears when the seam is sewn, as long as it was placed correctly.

What is the difference between staystitching, basting and easestitching?

Staystitching is sewn through one layer, at normal stitch length, and stays in. Basting is sewn through two or more layers, at a long stitch, to hold them together temporarily, and comes out. Easestitching is a long stitch on one layer, inside the seam line, that you pull up to shorten an edge on purpose, as on a sleeve cap. Staystitching holds a length; basting holds a position; easestitching changes a length.

What are the most common staystitching mistakes?

• Staystitching on the seam line or outside it. The stitches then show on the finished garment. Keep it 3 mm (1/8 in) inside the seam line: at 1.2 cm from a 1.5 cm edge.
• Doing it later. Staystitching after the piece has been handled for a week locks in the stretch that has already happened. Immediately after cutting is the whole point.
• Sewing against the grain. Running from the center front up to the shoulder on a neckline pushes the threads the wrong way and can stretch the edge a little rather than holding it.
• A long stitch. A 4 mm basting stitch does not hold; it eases. Use the garment stitch length.
• Stretching the fabric as you sew. Holding it taut at both ends does what staystitching is meant to prevent.
• Staystitching knits. The line breaks the first time the neckline stretches. Use a neckband, a binding or clear elastic.
• Skipping it on "stable" fabric. Quilting cotton stretches less than viscose, but a round neckline is still a curve across the bias. The two minutes it takes are always worth it.

When should you staystitch instead of relying on the facing?

The facing does not hold the neckline to size; it is sewn to whatever size the neckline has become. Staystitch the garment edge, then sew the facing to it. If the pattern uses a bias binding or a neckband, staystitch the woven garment edge anyway: the binding is itself stretchy and will follow a stretched edge faithfully. Where a neckline has already gaped on a finished garment, the gaping neckline post explains the rescue, but staystitching is the prevention.

On a garment with a lot of bias, such as a circle skirt whose entire waist crosses the bias, staystitching the waist is the difference between a skirt that fits the waistband and one that has to be eased in. The same goes for any piece cut on the bias on purpose; see how to cut fabric on the bias for how those pieces are handled from cutting onward.

Patterns' instructions place staystitching as the first step for a reason. In a Sewly sewing guide it is listed on the pieces that need it, and if you are unsure what the step means while you are sewing, you can ask the guide directly.