Guide to sewing with knit fabric easily

This guide will teach you what knit fabric is and provide tips for working with it so that you can enjoy sewing your first projects in no time!

Are you interested in sewing with knit fabric? If you want to make you or your family clothing like t-shirts, hoodies, casual stretchy dresses, or even underwear, then you will want to use some kind of knit. Sewing with knits is great because the patterns are typically very easy to work with. They tend to have a simple design, which means fewer pattern pieces to cut and sew together. They also don’t really need closures like zippers or buttons, unless they’re there for style.

And yet, working with knit fabric can be intimidating at first. There definitely is a learning curve, but once you’ve taken some time to figure it out, you’ll be so glad you did!

So here is a guide to getting started, as well as tips to avoid the most common problems of working with knit fabric.

What is knit fabric?

In case you’ve heard the term used but don’t actually know what it is, knit fabric is quite literally fabric that is made from little threads all knit together! Imagine knitting needles, but with huge, super fast machines instead. Just like a knit toque or sweater, it has natural stretch, whether there is any spandex in it or not. This is opposed to woven fabric, which is woven on looms and has much less stretch.

Different kinds of knit fabric

There is a wide variety of kinds of knit fabric. They are all knit slightly differently, to give the fabrics different qualities such as stretch, drape, thickness, etc. Most common are jersey, which is your typical t-shirt fabric; rib knit, which can be 1×1 or 2×2 and is used for collars and cuffs as well as whole garments; interlock, which is common in baby clothes; and French terry, used for sweaters and sweatpants.

Beyond that, there are of course the different kinds of textiles. Knits can be made with cotton, rayon, polyester, and even merino (wool). They are also often mixed with a certain amount of spandex to give them extra stretch and recovery.

Right and wrong side

It can be difficult to tell what is the right and wrong side of knit fabric. Sometimes, as in interlock or rib knit, there is no difference. Jersey has a right and wrong side, but it can be a little difficult to distinguish, simply because the knit stitches are so small and you need to look closely to be able to see. Here is a a very close up picture of the knit stitches on the right side and purl stitches on the wrong side. The edge of the right side is rolling towards the wrong side.

Once you’ve cut out your pieces, you might find it helpful to put pieces of masking tape on the wrong side of each piece so that you don’t get them mixed up.

Grainline and why it matters

It’s important to cut along the grainline properly! I’m sure we’ve all had cheap shirts with side seams that twisted to the front and back after one wash. That’s because they weren’t cut properly on the grainline. The grainline runs parallel to the selvage (machined edge) and will typically be going up and down your body. The cross grain runs perpendicular to the selvage and will be going across your body (because it has the most stretch). When you buy your fabric, it will be cut along the cross grain.

Often you will be cutting on the fold, so you need to make sure that the knit fabric is folded along the grainline. This can be a bit finicky with knits because they want to cling together, but it really is important, so try to get it right!

What kind of needles and pins/clips to use with knit fabric

Knits are easy to poke holes in. I’ve had really nice garments I made practically shred up after a few months of use because of holes all over the place, so beware!

You need to use sewing machine needles that are designed for knit fabric. If you are using something without spandex, then you can use jersey/ballpoint needles. If there is a spandex content, then you will want to use stretch needles. This goes for your sewing machine as well as your serger, if you have one.

You can also use something called a twin needle, which can be used on any sewing machine. It gives the same look as professional clothing with the two parallel lines of stitching and has a good amount of stretch. Just be sure to get one that is meant for stretch or jersey!

For this same reason, I actually prefer to use clips instead of pins when possible. But if you don’t have them, try to keep your pins inside of the seam allowance. If there is a part where you can’t do that, then try to be extra careful putting them in, trying to stick them between the threads rather than through them.

Sewing knit fabric with a serger

If you have a serger to sew your knits, that’s great! It will give you nicely trimmed seam allowances and lots of stretch. Sergers work really well with knits, but there probably are a few adjustments you will need to make.

First, make sure to use stretch or jersey/ballpoint needles.

Always test out some of your scraps on your serger before you start. I like to first adjust my stitch width and length according to my liking, then give it a try. After that I might need to adjust the looper tensions, but usually having all the tensions right around 4 works great.

If your machine has differential feed, you will probably want to adjust it. When you sew knits, the seam might stretch and get wonky. The differential feed helps to combat this. So if the seam is a little stretched, turn the differential feed up a little. If it’s really stretched, turn it up more. Just keep running your scraps through for test runs until you get it right.

Sewing knit fabric with a regular sewing machine

It will be easier if you make all of your seam allowances only 1/4 inch rather than 1/2. Otherwise you will have to trim your seam allowances after sewing.

Again, make sure you are using stretch or jersey/ballpoint needles.

Reduce the presser foot pressure slightly if you can (refer to your machine’s manual for this). My machine doesn’t have adjustable foot pressure, so I use a walking foot instead, which makes a huge difference in the pressure. My machine came with a walking foot, but I also previously bought this set of sewing feet which comes with one. This step helps to not have stretched out, wavy seams.

Next, reduce the needle tension slightly. For my machine, I set it to 3 (normal is 4).

Now you can sew the seam with a narrow zigzag stitch or the lightning bolt stitch if your machine has it (1/4 inch from the edge). Your machine might also have some other stretch stitches that you can try.

OPTIONAL: Zigzag along the very edge of your seam (I use stich length 2.5, width 5). This isn’t completely necessary, but it will make for neater and stronger seams.

Now you can confidently and beautifully sew with your knit fabric!

Did you find any of these tips helpful? Let me know in the comments below! And if you’re looking for an easy, adorable knit fabric project, check out my tutorial on how to make a little girls boho shirt here.