If you're looking for a quick and gratifying sewing project, knitwear is an excellent place to start. After all, knit fabrics are pretty easy to fit and usually don't need fiddly closures. With knit fabrics there's not a lot standing between you and a garment that's so comfortable you may never want to take it off.
Except for one thing: hemming.
Hemming knit fabrics is often the trickiest part because you need to make sure the openings stay stretchy enough to pull on and off your body. Hem a knit fabric the same way you would a woven one and it might get wavy or the stitches might pop when you try to stretch it over your head. Follow our rules, and you'll be hemming happy in no time.
A Few General Rules About Hemming Knits
- Knits do not fray like woven fabrics do, so you only need to turn the hem under once.
- Always use a ballpoint or stretch needle in your machine , which will glide through the looped knit fabric without piercing and breaking the fibers.
- If you have one, use a walking foot on your machine. The two layers of fabric feed evenly under the foot, which results in a flat hem instead of a wavy one.
- Stabilize the knit fabric you're going to hem , especially if it's lightweight. Use fusible elastic interfacing, fabric spray starch, wash-away or tear-away stabilizers or knit stay tape — basically anything that slightly stiffens the fabric so it's less likely to curl, stretch out under the presser foot or get sucked into your feed dogs. For the cotton jersey fabric in the photo below, I attached a strip of fusible elastic interfacing before turning up the hem.
Best Stitches to Hem Knits
1. Zigzag Stitch
The zigzag stitch allows the thread to stretch with the fabric . Turn the hem up as much as you want, then use a zigzag stitch to secure it. A narrow zigzag stitch is less noticeable.
Again, this stitch works best if you stabilize the fabric and use a walking foot. You can see the difference in hem waviness above.
2. Double Needle
To get a more professional-looking hem, turn up the hem and sew with a double needle (also called a twin needle) from the right side of the fabric. The bobbin thread will zigzag between the parallel stitches, giving you a stretchier hem.
If you have a serger, you may opt to first serge along the raw edge before turning up the hem so the underside looks more like a professionally coverstitched hem (assuming the thread colors match).
3. Stretch Stitch a Blind Hem
You may have sewn a blind hem on woven fabrics, but you can also use a variation of this stitch on stretchy fabrics.
Many modern machines have this stitch function, which is essentially a zigzag blind stitch. This creates a hem that is attached to the garment in intermittent stitches, so the stitches are less visible (as long as the thread color matches the fabric). This hem is ideal for garments such as knit pencil skirts or unlined knit blazers, where you want a more polished finish than you would on more casual knitwear.
First, press up your hem as usual. Then fold the hem back toward the right side of the garment, leaving a narrow edge of the hem that will be sewn on.
You can use a blind hem foot on your machine if you have one, but it's not required. Test the stitch on a scrap to see how wide to make it and where to position your needle. From the wrong side, sew along the exposed hem edge, making sure the wide zigzag catches the fold of the garment every few stitches. Press the hem down.
4. Fabric Bands
If you are sewing a knit top and would prefer to hide all your stitching, you can finish the sleeves and/or bottom hem with a separate folded band of fabric. The fabric doesn't have to be stabilized for this finish.
Measure the circumference of the opening to be hemmed. Cut a separate rectangular piece of fabric (making sure the stretch is going the same way as the stretch of the garment) that is slightly smaller than your garment opening. This will ensure that the bands won’t get baggy after pulling them over your hands or shoulders.
Now serge or zigzag stitch the short edges of the band together. Fold the long edges of the band wrong sides together. Serge or zigzag stitch both layers to the right side of the garment, matching seams. Press the band down.
The coverstitch is the ideal way to hem most knit garments , and you will typically see this finish on store-bought knitwear like T-shirts and leggings. The right side features parallel rows of straight stitching, with the underside in a loop of thread that allows maximum stretch.
You need a special machine for coverstitching, though, which makes it the least accessible option. Many higher-end sergers have a coverstitch function that requires a slightly different threading and blade configuration. There are also stand-alone coverstitch machines you can buy if you're super motivated.
This sewing technique works like the double-needle finish, except you can adjust the differential feed, so the fabric doesn't stretch out as you sew. You press up the hem, coverstitch from the right side and admire your pro finish!
Hemming knits isn't actually a lot harder than hemming woven fabrics. Just follow the tips here and you'll be that much closer to getting a new piece of great-looking knitwear.