Hemming

Hem Knit and Stretch Fabric

Hem a T-shirt, jersey or other knit fabric using a stitch that stretches, so the thread does not snap when the garment is worn.

Confident Beginner1 hrMachine

What you will learn

Stretch stitches
Sewing without stretching the fabric
Ballpoint needles

Materials and tools

Sewing machine
Ballpoint or stretch needle, 75/11 for light jersey and 90/14 for heavier knits
Polyester thread
Twin needle, 4 mm, optional if the machine takes one
Pins or clips
Iron and board
Scrap of the same fabric

Before you start

Mark the hem length on the body, confirm it and choose a 1 in (2.5 cm) hem allowance. Only after the length is confirmed, trim the fabric 1 in (2.5 cm) below the marked length. Press with a low heat, since many knits melt or mark easily.

Step by step

Fit a ballpoint needle. Its rounded tip slides between the knit's loops instead of cutting them. Switch the machine off and unplug it before changing the needle.
Fold the hem up 1 in (2.5 cm) to the wrong side and press lightly. Do not stretch the fabric as you press. Pin or clip every 2 in (5 cm).
Choose a stitch. Use a narrow zigzag (width 1 mm, length 2.5 mm), the machine's stretch stitch or a twin needle. A straight stitch will break when the fabric stretches.
Test the stitch on a double layer of scrap, folded as the hem will be. Stretch the scrap gently. The stitches should stretch with it and not snap. Adjust the length and tension if needed.
Sew the hem with the right side facing up. Let the machine feed the fabric. Do not pull or push, because stretching the fabric while sewing causes a wavy, rippled hem.
If using a twin needle, thread both needles as the manual shows. Sew slowly. The back shows a zigzag that gives the hem its stretch.
Press the hem lightly with a low heat and a pressing cloth. Do not press hard on stretchy fabric, which can mark it.
Try the garment on and stretch the hem. If threads snap, unpick them and use a more elastic stitch.

Tips for a neat result

A walking foot or a lowered presser foot pressure, if your machine allows it, helps the layers feed evenly.
Knit edges roll. They do not fray, so a raw edge is fine for a casual hem.

Common mistakes and fixes

The hem is wavy.

The fabric stretched as it was sewn. Let the machine feed it and support the fabric weight with your hand.

Skipped stitches.

The needle is wrong for the fabric. Use a ballpoint or stretch needle of the correct size.

Stitches snap when the garment is pulled on.

A straight stitch does not stretch. Use zigzag, stretch stitch or twin needle.

Safety and fabric care

Unplug before changing a needle. Use low heat on synthetic knits.

Check your result

The hem lies flat without ripples.
The stitching stretches when the fabric does, with no broken thread.

When to use a professionalTake the garment to a tailor if the knit is very fine, sheer, or has a printed pattern that must stay in line. Cover-stitch hems on sportswear are best left to a professional.

Projects that use this

Shorten Simple SleevesConfident Beginner1 hr