I’ve noticed that a lot of people get really scared about sewing stretch or knit fabrics. I was too until I gave it a try a few years ago – and you know what? It’s not so hard! Really!!
Basically the main tricks are to use the right needle and to use stitches that will maintain the stretch of the fabric. There are a few other simple techniques and gadgets you should know, and then you’re set to sew!
// Choosing a Needle //
I think the most important aspect of sewing stretch fabrics, is making sure you have the right needle on your machine! For knits, you want to have a ball-point needle, as sharp needle meant for wovens can tear holes in knit fabrics.
For jersey knits, or any knit really, look for a needle that says Jersey/Ballpoint.
Another option is Stretch needles, which is meant for really stretchy fabrics like swimwear and other fabrics with a high amount of spandex or lycra. But can also be used for other knits.
If a Universal needle is all you have on hand, You can get away with using it on heavyweight or sturdy knits. But I would avoid it on any light-mid weight knits at all.
The last needle you see in this photo is a twin needle, which is used for hemming. But I’ll get into this later in this post!
// Sewing Seams //
There are two main ways that I sew seams on stretchy fabrics:
1. Zig Zag stitch
The best stretch stitch on a regular sewing machine is a zig zag stitch. This stitch will allow the fabric to stretch a little after sewing.You may need to adjust the stitch width and stitch length of the zig-zag depending on the weight of your fabric, so make sure you always test it out on scraps at the beginning of a project.
A lot of machines have other built in stretch stitch options, that many people swear by. I personally don’t use them, because I don’t think they add that much value – but check your sewing machine’s manual, as you may find you like using those stitches better.
Another option, if you have a serger/overlock machine, is to use that to sew your seams on knits. These stitches have stretch in it.
Note: most Sergers have a 1 needle or 2 needle option. My machine was set up with just one needle when I did this sample, so thats what you see above. But using the 2 needle (4 thread) option is probably best for seaming knits as its sturdier while still providing stretch.
// Edge Finishing //
1. Zig Zag with no finish
One of the super cool things about stretch fabrics is that you often don’t have to finish the edges as they won’t fray (unless it’s a loosely woven sweater type fabric). And if it is a lighterweight knit, like a jersey knit, the edges will curl – which is a cute edge finish itself!
2. Zig Zag and trim
If you used a zig zag or other stretch stitch on a sewing machine, then you can either leave the seams as is – or you can neatly trim away the excess fabric. That’s it :) no stress!
3. Serger / Overlock or Zig Zag with Overlock
If you used a serger to sew your seams you don’t need to neaten anything at all!
Or you can sew the seam with a zig zag, but then finish the edge with the overlock machine for a clean look.
// Hem Finishing //
Let’s talk about folding your hem…
1. Double fold
Ok, so most knit garments are actually hemmed with a single fold. But you can double fold a knit hem just like a woven hem. I would only do this with certain knits, though, as it can create extra bulk. So make sure to test this out with your fabric.
2. Single fold with raw edge
Most knit garments are turned under just once. And because most stretch knits don’t fray, you can choose to keep the unfinished edge.
3. Single fold with overlocked edge
If you like clean finishes, you can also choose to first finish the edge with a serger/overlocker and then fold under once.
// Hem Stitching //
1. Zig Zag stitch
The easiest way to stitch your hem is using that zig zag stitch!
I’m going to show you quick this basic zig zag hem with the different edge finishes…
If you kept the raw edge with a single fold, you can choose to trim the excess if you want.
Here is the zig zag hem with the double fold hem.
And here is the zig zag hem with the overlocked single fold.
2. Twin Needle
My absolutely favourite method of hemming stretchy fabrics is using a twin needle. I don’t often mention it though, as it seems to terrify many people. But twin needles are awesome and you will love them if you try! You don’t need a special machine, and the resulting stitch has a great amount of stretch built into it. You can get these twin needles in different widths, too.
Here’s how to use it…
You simply thread your machine using 2 spools of thread instead of one. Most machines have a spot for a second spool, but if yours does not, you can put the second spool in a cup/mug as a hack!
Thread your machine with both threads at once, as if it is just one thread.
When you get to the twin needle, thread one thread through each needle.
Set your machine to a **straight stitch**.
You will have to do this top stitching on the outside (right side) of the fabric.
P.S – this can be a little tricky with wide hems that go beyond your machines measures. My trick is to iron my hem, then place a piece of tape the correct distance from the needle on my machine, and then use that as my sewing guide.
Update: Since posting this, June had the brilliant idea of using a stack of post-it note pads, with the bottom sheet peeled off. Stick it at the desired location and then it provides a little “wall” that the fabric can run alongside. I think this might be even better than my tape solution!
Here is what a twin needle stitch looks like. You will have two straight stitches on the right side of the fabric, with a zig-zag like stretch knit on the wrong side of the fabric.
// Preventing Waviness and Stretching //
I think one of the biggest complaints with sewing stretch fabrics, is the waviness and mis-shapen stretch effect that can happen (like shown above).
There are a few different measures you can take to prevent this…
1. Don’t pull/stretch your fabric!
The biggest way to prevent this is, when sewing, is not to stretch the fabric as you sew unless the pattern calls for it. If you stretch your garment, it will more than likely come out misshapen.
Also, do not let your garment fall to the ground as you sew, as this can automatically stretch your fabric as you sew. So support that fabric as you feed it through the machine!
2. Stretch fusible hem tape
There are different kinds of knit/stretch fusible hem tape (this is an example of one I had in my stash). Follow the directions on the packaging to apply the tape to your seam or hem. This can help stabilize the fabric for less stretching.
3. Walking Foot
If you have a walking foot/even feed foot for your machine, this can be helpful with knits!
A walking foot has an extra set of of feed dogs on top that work with your machine feed dogs on bottom, and is used with slippery or tricky fabrics to help keep your fabric in place and evenly feed both layers through the machine without pulling, stretching or allowing your fabric to “eat” the fabric.
So with knits, this is helpful in preventing that stretching!
4. Adjusting Presser Foot pressure
If you don’t have a walking foot, you can try adjusting your machine’s presser foot pressure. If your presser foot is set too high and applying too much pressure, it can stretch the fabric as it feeds through the machine. So read your machine’s manual to see how you can adjust this.
5. Press, press, press
If all else fails, press! Even better, hover your iron right above the stretched stitches and hit it with some steam – this can help shrink it back up.
// Other Tips //
1. Just like in regular sewing projects, always prewash and dry your fabric in the way you will after sewing. Keep in mind that many stretch fabrics shrink a lot. I like to tumble dry mine after washing, as I know that’s more than likely how I’ll dry them after sewing my clothing.
2. When cutting make sure that you lay your pattern pieces so that the stretchiest part of the fabric is going across your body (side to side) rather than up your body (up and down) – or else you won’t be able to get it on!!
3. Another machine I do not show or mention above is a Coverstitch machine, which can be used for hemming knits. It creates a look of a twin needle on the right side, and loops like a serger on the wrong side. This is how you see most RTW t-shirts hemmed!