How to Sew Knit Material: Needles, Stitches, and Tips

What You Need to Know Before Sewing Knit Fabric

Sewing knit material successfully comes down to three essentials: the right needle, a stretch-capable stitch, and proper tension settings. Unlike woven fabrics, knitted fabric stretches in multiple directions, which means standard sewing techniques will cause skipped stitches, broken thread, or seams that pop when worn. Once you understand how knit behaves, the process becomes straightforward and rewarding.

Knitted fabric is constructed from interlocking loops of yarn rather than interwoven threads. This loop structure is what gives it elasticity. Common knit types include jersey, ribbing, interlock, French terry, and ponte. Each has a different stretch percentage and weight, which influences how you sew it.

Choosing the Right Needle for Knitted Fabric

The single most common mistake sewers make with knit material is using a universal needle. A universal needle has a slightly sharp tip that pierces and can cut through the yarn loops, causing runs or holes. Instead, use a ballpoint or stretch needle, which has a rounded tip that pushes between the loops rather than through them.

• Ballpoint needle (Jersey needle): Best for most medium-weight knits like cotton jersey and interlock.
• Stretch needle: Designed for highly elastic fabrics such as spandex blends and swimwear knits. It has a special scarf to prevent skipped stitches.
• Twin needle: Creates two parallel rows of stitching on the right side and a zigzag on the wrong side, ideal for hemming knits with a professional finish.

Needle size matters too. For lightweight knits, use a size 70/10 or 75/11. Medium knits work well with an 80/12, while heavyweight ponte or double-knit fabric calls for a 90/14.

Best Stitches to Use on Knit Material

A straight stitch does not stretch, so it will break when the seam is pulled. You need a stitch that can move with the fabric. Here are the most reliable options:

Zigzag Stitch

The most accessible option on any sewing machine. Set the stitch width to around 2 to 2.5mm and the length to 2 to 3mm. This gives the seam enough flexibility to stretch without breaking. It works well for T-shirts, leggings, and casual knit garments.

Lightning Bolt or Triple Stretch Stitch

Available on many modern machines, this stitch sews forward, backward, and forward again over each stitch. It creates one of the strongest stretch seams possible on a regular sewing machine and is especially good for waistbands and areas under stress.

Overlocker or Serger Stitch

A serger trims the seam allowance, sews the seam, and finishes the edge in one pass. A 4-thread overlock stitch is the industry standard for sewing knit fabric, used in virtually all commercially made T-shirts and activewear. If you sew knits regularly, a serger is a worthwhile investment.

Coverstitch

A coverstitch machine creates the flat, two-needle hem you see on the inside of store-bought knit garments. It is used specifically for hems and neckbands rather than seams. If you want truly professional-looking results when sewing knit material, a coverstitch machine is worth considering.

Thread and Tension Settings for Knitted Fabric

Use polyester thread rather than cotton when sewing knit material. Polyester thread has a small amount of natural elasticity that cotton does not, which helps it move with the fabric and resist breakage. A thread weight of 50wt or 40wt works for most knit projects.

Tension is another area where knit fabric behaves differently. If tension is too high, the seam will pucker and pull. Start with a slightly reduced tension setting and test on a fabric scrap. The goal is a seam that lies flat and stretches smoothly when pulled gently from both ends. On most machines, reducing the upper tension by one or two numbers from the default is a good starting point.

How to Cut Knit Fabric Without Distortion

Knitted fabric is prone to stretching out during cutting, which leads to pieces that are longer or narrower than intended. Follow these steps to get accurate cuts:

1. Prewash and dry the fabric before cutting to account for any shrinkage.
2. Lay the fabric flat on a cutting surface without stretching it. Do not let it hang over the edge of the table.
3. Use sharp fabric scissors or a rotary cutter. A dull blade drags the fabric and distorts cuts.
4. Pin pattern pieces with fine ballpoint pins or use pattern weights to hold the fabric without distorting it.
5. Cut in a single layer when working with slippery or very stretchy knits, as two layers can shift.

A self-healing cutting mat and a rotary cutter are particularly useful here, as they allow you to cut without picking up the fabric at all.

Handling Knit Fabric While Sewing

One of the most important rules when sewing knit material is never pull or push the fabric through the machine. Let the feed dogs move the fabric at their own pace. Pulling stretches the fabric and causes wavy, uneven seams.

If your machine is skipping stitches or the fabric is tunneling under the presser foot, try these adjustments:

• Reduce the presser foot pressure if your machine allows it.
• Use a walking foot, which moves the top layer of fabric in sync with the feed dogs below. This is especially useful for thicker or heavier knits.
• Place a strip of tissue paper or stabilizer under the fabric when starting a seam to prevent it from being pulled into the machine.
• Hold the thread tails when beginning to sew, rather than letting them pull through the needle plate.

Knit Fabric Types and Their Sewing Differences

Not all knitted fabrics behave the same way. Understanding the differences helps you choose the right approach for each project.

Ponte is often the easiest knit for beginners because its low stretch means it behaves more like a woven fabric while still offering comfort and ease of movement. Cotton jersey and French terry are excellent next steps.

Hemming Knit Fabric Neatly

Hems are where many sewers struggle with knit material. The fabric wants to curl, especially at the cut edge of jersey, and a straight stitch will cause the hem to pop or look rippled.

The most practical hemming methods for knits include:

• Twin needle hem: Creates two parallel rows on the right side that look professional and allow stretch. Use a 2.0 or 4.0mm twin needle and reduce tension slightly.
• Zigzag hem: Simple and effective. Fold the hem up and sew with a narrow zigzag along the fold edge.
• Coverstitch machine hem: The most professional result, used in ready-to-wear garments. The stitch stretches in both directions and lies completely flat.
• Blind hem: Some machines have a stretch blind hem stitch that produces an almost invisible finish on heavier knits like ponte.

For curling jersey, press the hem with steam before sewing to help it lie flat. Do not iron directly with heavy pressure, as many knit fabrics will stretch out under the heat of an iron unless you use a pressing cloth and lift rather than glide.

Common Mistakes and How to Avoid Them

Even experienced sewers run into issues with knitted fabric. These are the most frequent problems and their solutions:

Skipped Stitches

Almost always caused by the wrong needle. Switch to a stretch needle and replace it if it has been used for more than 8 to 10 hours of sewing. A bent or dull needle causes skipped stitches even on woven fabric.

Wavy or Stretched Seams

This is caused by pulling the fabric or sewing with too much tension. Reduce tension and let the fabric feed naturally. A walking foot resolves this in most cases.

Seams That Pop When Worn

This happens when a non-stretch stitch is used. Switch to a zigzag, lightning bolt stitch, or serger. Always test the stitch by pulling the sewn seam gently before wearing or finishing the garment.

Fabric Eaten by the Machine

Lightweight knits can be pulled down into the needle hole at the start of a seam. Hold thread tails firmly, begin sewing slightly away from the cut edge, or place a small piece of tear-away stabilizer under the start of the seam.

A Practical Starting Point for Sewing Knit Material

If you are new to sewing knitted fabric, start with a simple project on a stable knit like ponte or interlock. These fabrics have less stretch and are much more forgiving than jersey or spandex blends.

Before cutting into your main fabric, always do a test run on a scrap piece. Sew a seam about 10 centimeters long, then pull it firmly. If stitches break, adjust your settings. If it stretches and holds, you are ready to cut. This five-minute test saves hours of frustration on finished garments.

Knit fabric opens up a wide range of comfortable, wearable garments that are difficult to achieve with woven fabrics alone. With the right tools and an understanding of how knitted fabric behaves, sewing with it becomes one of the most practical and satisfying skills in a home sewer's toolkit.