A Neat Way to Finish Knits Using Just a Sewing Machine

If you’ve ever sewn with knits, you know that finishing the raw edges can be a real challenge — especially when you don’t have access to a coverstitch or overlocker (serger). Knitted fabrics need flexibility at the seams, but many common finishing methods either stretch the seam out of shape or cause the stitches to break over time. After testing different techniques, I’ve come up with a simple method that gives you a clean, stretchy, and professional-looking finish using just a regular sewing machine and a bit of elastic.

This method is ideal for anyone who loves making clothes from knitted fabrics at home.

Why Finishing Knits Is Difficult Without Specialized Equipment

Knit fabrics are naturally stretchy, which makes them comfortable to wear but tricky to sew. Most standard sewing machine stitches aren’t designed to stretch, and when you topstitch or finish a seam, the edge can easily stretch out during the sewing process. This often leads to seams that:

• Appear wavy or distorted when stretched

• Lose their elasticity at the seam line

• Gather or ripple along the edge

• Sometimes break or pop during wear

To illustrate this, I’ll include a photo showing two common finishing methods:

1. A seam folded under and topstitched with a straight or stretch stitch ( example shown in orange color thread)

2. A seam that was overlocked and then topstitched ( example shown in black color thread)

In both samples, the finished seams look fine when flat, but when stretched, they distort noticeably. The stitch lines lose their flexibility, and the seam does not recover well.

My New Finishing Method: Seam Elastic for Structure and Stretch

To solve this, I began experimenting with soft elastic as a support structure within the seam itself. The idea was to preserve stretch while also adding a clean finish — and it worked better than expected.

Here’s what you need to try it yourself:

Materials:

• Soft elastic, approximately 1.2 cm wide (this is the type commonly used for lingerie straps — smooth, flexible, and lightweight)

• A stretch needle for your sewing machine

• A zigzag or stretch-compatible stitch setting

Instructions:

1. Sew your garment seam as usual, using a stretch stitch or narrow zigzag for flexibility.

2. Cut a strip of elastic equal in length to your seam.

3. Align the elastic with the edge of the seam allowance on the wrong side of the fabric.

4. Stitch the elastic to the seam allowance, close to the raw edge, using a zigzag or three-step zigzag stitch. Do not stretch the elastic as you sew, that's very important!

5. Trim the seam allowance, cutting away any excess fabric close to the elastic edge.

6. Fold the entire seam allowance, including the elastic, toward the inside of the garment (so the raw edge is now enclosed under the fold).

7. Topstitch through all layers, securing the folded edge in place.

What Is Plush Elastic?

Plush elastic is a soft, stretchy elastic with a fuzzy, velvety side that feels gentle against the skin. It’s commonly used in garments like lounge shorts, bralettes, waistbands, and baby clothes—anywhere comfort is a priority. What makes it special is that soft surface, which helps prevent chafing and adds a cozy touch to stretch garments.

Inside, plush elastic has a stretch core (usually rubber or spandex) wrapped in a knit or woven layer made from polyester or nylon. The plush side is brushed to give it that soft, cushiony texture, while the other side is usually smoother and slightly firmer.

This type of elastic is perfect for home sewists working with knits, especially if you're sewing comfy clothes or lingerie and don’t want scratchy elastic touching the skin. It’s also very user-friendly—no need for a serger or industrial machines. You can sew it directly to your fabric using a zigzag or stretch stitch, making it ideal for hobbyists or small-scale makers who want professional-looking results with basic sewing equipment.

Why This Works

This method provides several key advantages:

• Preserves Stretch: The elastic moves with the fabric, so the topstitch line doesn’t break or pucker when worn.

• Adds Structure: It stabilizes the seam edge, preventing distortion and stretching during sewing or wear.

• Neat Appearance: The raw edge is completely enclosed, and the topstitched finish looks polished and intentional — even on the inside.

• No Overlocker Required: You only need a standard sewing machine and a zigzag stitch.

When to Use This Technique

This method works particularly well for:

• Necklines and armholes on knit tops and dresses

• Seam finishes in activewear or stretch lingerie

• Lightweight jersey fabrics that tend to curl or warp at the edge

• Anywhere you need a flat, clean seam that maintains its stretch

If you’re working with knits and want a professional-looking result without investing in extra machinery, this elastic method is a great addition to your sewing toolbox. It’s simple, effective, and gives your projects a clean finish that holds up through wear and washing.