A stretch stitch is a type of machine or hand stitch that is designed to expand and contract with stretchy fabrics to prevent popped threads and broken fabrics. Stretch stitches are necessary when working with stretchy fabrics because regular straight stitches cannot stretch enough to accommodate the expansion of the fabric. There are several types of stretch stitches that can be used for sewing knit seams, including:

• Triple Straight Stitch: This stitch is essentially a straight stitch, but the stitch goes forward and backward as it goes, making it stretchy and strong.

• Zigzag Stitch: A zigzag stitch is naturally quite stretchy and is a great choice for sewing knit fabrics. When sewing seams, put your settings on a narrow zigzag and test a width of 1.5 and length of 2.5. Stretch the fabric and see if the stitches break. If they dont, then you have the perfect stretch stitch.

• Knit Stitch: This stretch stitch is used for sewing and overcasting knit seams and provides quite a big amount of elasticity.

• Stretch Buttonhole Stitch: This stitch is similar to the triple straight stitch but has only two steps instead of three.

• Overlock/Overedge Stitch: This stitch is handy because it gives you a similar effect as a serger because it forms and finishes the seam all at once, but without the trimming.

The best stretch stitch to use for a particular project depends on the fabric and the desired outcome. It is important to consult your sewing machine manual to determine which stitches are best to use for your project.