10 tips for sewing knits perfectly

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Having trouble with wavy seams, snapped thread and holes in your homemade knit garments? These 10 tips will help you overcome problems and you'll be sewing knits perfectly in no time! Check it out at www.cucicucicoo.com

When a person learns to sew, the first projects are always with woven fabric. When you go to a fabric shop, you’ll notice that most fabrics are woven. And when you browse sewing projects on Pinterest, nearly all of them use woven fabric.

But take a look at your own wardrobe, or that of your kids. I’m willing to bet that you have a pretty high percentage of garments made with knit fabric. (Such as T-shirts, leggings, sweatshirts/pants and sweaters.) So why do DIY sewing projects focus mostly on wovens?

Simply put, wovens are a whole lot easier to work with (except for some fussy fabrics like chiffon, which tend to cause much swearing). However, knits have a LOT of advantages that woven fabric doesn’t, which is why they’re so frequently used in clothing.

But in order to understand all this, let’s talk a moment about the difference between woven and knit fabric, and then we’ll get to 10 life-saving tips for sewing knits easily and with wonderful results!

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Wovens vs. Knits

The difference in knit vs. woven fabric. (Image from http://www.onelittleminuteblog.com)
Click for image source.

The first thing to understand is that woven and knit fabrics are NOT interchangable! When you are following a sewing tutorial or pattern, pay close attention to the type of fabric called for. Wovens and knits are intrinsically different and have totally different characteristics.

Look at the image above (thank you to One Little Minute for the great graphic!). Woven fabrics are created with a weaving loom, with a warp and a weft, or in layman’s terms, vertical and horizontal threads that overlap each other. Knit fabrics, on the other hand, are created with a single thread that is looped around itself over and over again, just like the fabric that is created on knitting needles. The picture below shows the right and wrong sides of a woven cotton (red) and a knit cotton (green).

Learn to sew knits perfectly! The difference between woven and knit fabrics. More tips at www.cucicucicoo.com

This difference in construction method makes for a lot of other differences. The most important is that knit fabric stretches while woven fabric doesn’t. (Unless the fabric has been woven with some percentage of stretch thread, which is how stretch jeans have that extra bit of stretchiness that regular jeans don’t.)

Because knits are by stretchy by nature, garment patterns using knits usually have what is called negative ease. This means that the finished garment is actually smaller than your body’s measurements. This is because knits are meant to hug the body to a varying degree, and it will stretch over the body for a perfect fit. This also means that garments made with knit material are more forgiving in terms of sizing.

Knits also tend to be more pliable than wovens. This means that they drape easily and are very soft. There are different weights of knits, from relatively lightweight to thicker sweatshirt knit, however there are not as many types and weights of knit fabric as there are woven fabric.

Learn to sew knits perfectly! The difference between jersey and interlock knit fabrics. More tips at www.cucicucicoo.com

However, there are different types of knit material, too. The two most typically used are jersey and interlock. In the photo above, the striped fabric is jersey and the yellow fabric is interlock.

Learn to sew knits perfectly! Knit jersey fabric compared to a sweater knit in stockinette stitch. More tips at www.cucicucicoo.com

Jersey, what the classic T-shirt is made of, is basically a classic stockinette stitch, which has a very distinct front and back, unlike woven and interlock fabrics. Notice that the edges roll in towards the front of the material, just like they do with a classic knit sweater. It’s hard to see well because knit fabric has tiny stitches, but see how similar the stitches and edges of jersey fabric are to those of my Gemini sweater, which I finished knitting a couple of months ago but never got around to blocking, hence the rolled edges.

Interlock is a double knit, which basically means that there are two layers of knit material. This means that the front and back are the same and the edges don’t roll in, as you can see a couple of pictures above.

Having trouble with wavy seams, snapped thread and holes in your homemade knit garments? These 10 tips will help you overcome problems and you'll be sewing knits perfectly in no time! Check it out at www.cucicucicoo.com

Knit fabric is made in all different fibers, whether natural fibers or synthetic ones. It frequently has a small percentage of lycra or spandex (which are actually the same thing) to make it even more stretchy, which is great for neckbands and other parts that need to expand a lot.

If you’ve ever knit a hat or sweater, you’ll know that ribbing is usually worked around the openings, not only to keep the fabric from rolling, but also to make it stretchier to fit around the body part. (You can see ribbing worked on the arm cuffs of the sweater two pictures up.) Likewise, there is also fabric ribbing that is super stretchy and frequently used for cuffs and neckbands.

The picture above shows some different types of knit fabrics:

  1. solid colored cotton jersey
  2. printed cotton jersey
  3. interlock
  4. ribbing
  5. hemp jersey
  6. synthetic viscose knit
  7. hemp sweatshirt fleece

Due to the structure and stretchiness of knit material, it can be a little tricky to sew. It can stretch out of shape. The seams can easily get wavy. The thread can snap. Holes can form in it. Your final garment may end up too big or too small.

However, there are some tricks to get past these potential problems and the payoffs of a well-sewn knit garment are well worth figuring out how to sew this type of material! So, on that note, let me tell you my “10 U’s,” otherwise known as…

10 Tips for Sewing Knits Perfectly

1. Understand stretch.

Before you even start your project, you need to understand your chosen fabric. Not all knit material stretches in the same way. It depends on the way it’s been made, the fiber content, and quality. It can be two-way stretch (it stretches just horizontally or just vertically), or four-way stretch (it stretches both horizontally and vertically).

The very important thing to remember is that the direction of greatest stretch must go AROUND the body part so that it can open wide enough to fit over but still be snug around the body. If you accidentally position a leggings pattern, for example, so that the stretch goes up and down, the garment will stretch out lengthwise, becoming too long, and will most likely be very tight around the hips and legs.

If the garment you are sewing is relatively snug, a fabric’s percentage of stretch and recovery is very important. So let’s say you have a fabric that is nice and stretchy, but with little recovery, meaning that it gets stretched out without going back to its original width. If you are sewing a loose T-shirt, it probably won’t be a problem. However, if you sew leggings with it, you will end up with a garment that is too long and wide because it doesn’t pull back into shape after getting stretched over the legs and hips.

The best thing to do to avoid this problem is to calculate stretch and recovery with a ruler or gauge. This excellent article by Elegance and Elephants has a downloadable stretch gauge with very detailed instructions and photos explaining how to use it properly. Quality sewing patterns will indicate what percentage of stretch is necessary for the project, so make sure that your chosen fabric is at least that stretchy, if not more.

Learn to sew knits perfectly! Ballpoint pins and wonder clips help eliminate holes. More tips at www.cucicucicoo.com

2. Use the right pins.

Before you start sewing, you’ll probably need to pin your fabric pieces together. But not all pins are made the same. Regular straight pins are quite sharp to pierce the fabric. Ballpoint pins have a softer point which slips between the knit loops without of going through the thread itself. This keeps the fibers intact so that they don’t break when the fabric is stretched. Because heck, who wants little holes in their meticulously sewn garment?!

An alternative are Wonder Clips. These are special plastic clips that hold the fabric together without pinning. These are very useful if you don’t want to damage fabric with pins, however you can only use them on the edge of fabric, not anywhere in the center of the sewing surface.

I use these ballpoint pins* and these wonder clips* and am very happy with both.

Learn to sew knits perfectly! Ballpoint and stretch needles (single or twin) help eliminate holes. More tips at www.cucicucicoo.com

3. Use the right needle.

The same exact thing goes for sewing needles. Regular universal needles are quite pointy and will ruin the knit fabric. Make sure you get either ballpoint or stretch needles. Another really amazing needle for knits is the double needle (or twin needle). I’ll talk more about that in tip #5.

The needles in this picture are Schmetz 90/14 Stretch Needle* and Schmetz 4/75 Stretch Twin Needle*.

Learn to sew knits perfectly! Polyester thread keeps your stitches from snapping when the fabric is stretched. More tips at www.cucicucicoo.com

4. Use the right thread.

Thread doesn’t stretch as much as stretchy fabric, which means that it can easily snap. And that’s really annoying. This is why I only use polyester thread with knits. Some people seem to be able to use high quality cotton thread for stretchy garments, but I’ve had too many stitches on stretchy garments break with it. Some people use wooly nylon or stretch thread, but I haven’t used them myself.

There are lots of brands of polyester thread, but I almost always use Gutermann Sew-All poly thread* because it’s the easiest-to-find high quality polyester thread where I live in Europe.

Learn to sew knits perfectly! The stitches to use to keep your thread from snapping when the fabric is stretched. More tips at www.cucicucicoo.com

5. Use the right stitch.

Remember what I just said about thread snapping when a knit garment is stretched? The most important way to avoid this happening is to use a stitch that will expand with the fabric. Which means that a classic straight stitch is out of the question.

Your sewing machine probably has a variety of stitches and is sure to have at least one that will work with knits. The most common is the zig zag stitch (#5 above), but there are also the triple straight stitch (#3 above, which looks like three vertical dashed lines), the stretch stitch (#4 above, which looks like a jagged lightning bolt), and the triple zig zag stitch (#6 above, which looks like a dashed zig zag stitch). Always test these stitches out on a scrap of the fabric you’re using so that you can regulate stitch width and length, as well as tension.

Another option is to use a long straight stitch with a ballpoint or stretch twin needle*. I love using this needle for hems and at some point I’ll make a tutorial to show how to use it. Basically there are two top threads, and the bobbin thread zig zags between them under the fabric, allowing it to stretch. The resulting parallel lines of stitching also looks more professional than a simple zig zag.

And yet another option? An overlock machine (serger)! This sewing machine’s stitches are stretchy by nature, so perfect for knits.
Simple rectangle vest

6. Understand knit edges.

The wonderful news is that knits don’t fray, so you don’t have to finish off the edges if you don’t want. Remember, though, that the fabric edges of jersey roll to the front. This can be a desired effect, as on the front edge of this rectangle vest, because it hides imperfectly cut edges and just looks more finished. However, it can also be really annoying if you just want it to lie flat, such as when you’re sewing it. If this is the case, apply some iron-on stabilizer to the back of the fabric, or spray-on starch before sewing it.

7. Use the feed dogs properly.

The feed dogs are those jaggedy metal things sticking out of the needle plate on your sewing machine. They move front to back each time the needle goes up to move the fabric along. (Learn more about sewing machine anatomy here.) Sometimes it helps to pull the fabric a little from behind to move it along. DO NOT pull knit fabric because you will then sew it into place while it’s all stretched out.

One problem people frequently run into is that the fabric gets sucked down into the feed dogs when you start sewing it from the very edge. To avoid this from happening, start sewing a centimeter or so in from the edge, backstitch to the edge, and then continue sewing regularly.

How to use a walking foot. This sewing machine foot will save you headaches, making it possible to sew over thick layers and sticky or slippery fabrics, as well as keep stripes and plaids perfectly lined up! Part of the Learn to Sew series on www.cucicucicoo.com

8. Use a walking foot.

One common issue when sewing knits is that the seams pucker up and look wavy after sewing them. These last three tips help deal with this effect. The first and, in my opinion, easiest way to counteract seam waviness is to sew knit fabric with a walking foot. Like I explained in my walking foot lesson, this special foot has feed dogs on the top, too, meaning that it moves bulky, slippery or otherwise difficult fabrics under the sewing needle evenly.

How to sew PUL fabric (for waterproof layers in cloth diapers, pads, wet bags and changing mats) | www.cucicucicoo.com

9. Use tissue paper.

This is a trick that I’ve already shared in my lesson on sewing PUL and other laminated fabrics. While putting tissue paper between the fabric and the machine foot was useful in counteracting the stickiness of the laminated PUL surface, in the case of knits it works as a stabilizer. You can also try putting the tissue paper under the fabric too, which helps keep the fabric from getting pulled down into the feed dogs (see tip #7). The sewing needle creates a perforation, making the paper easy to remove afterwards.

Learn to sew knits perfectly! A hot steam pressing will eliminate most wavy seams. More tips at www.cucicucicoo.com

10. Use your iron.

I have never tried to hide the fact that I hate ironing, but it’s absolutely necessary to press fabric and seams when sewing. And when sewing knits, an iron can be your best friend because a good steam pressing will flatten out most wavy seams. The picture above shows normal zig zag horizontal and vertical stitching on scraps of 4-way stretch jersey with the edges folded over. I left the stitches marked A unironed, and gave the B stitches a quick steam pressing. It’s hard to tell in the picture, but the A stitches are quite wavy, while the B stitches are perfectly flat but equally stretchy.

Having trouble with wavy seams, snapped thread and holes in your homemade knit garments? These 10 tips will help you overcome problems and you'll be sewing knits perfectly in no time! Check it out at www.cucicucicoo.com

So, now that you know all about what makes knit fabric special and how to compensate for the problems arising from its stretchiness, grab some scraps and practice sewing knits a bit. When you feel comfortable sewing this type of fabric, move on to this refashion tutorial for a comfortable and useful accessory!

Learn to Machine Sew with Cucicucicoo: a free sewing course for beginners

This lesson on sewing knits is part of the syllabus of Cucicucicoo’s Learn to Machine Sew beginner’s sewing course! Don’t forget to share pictures of your work on Facebook or the Cucicucicoo Creations Flickr Group!

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*This post contains affiliate links.

54 thoughts on “10 tips for sewing knits perfectly”

  1. Fantastic tips. You can get sewing machine feet that are specifically for knits too (called a knit foot). Rather than pulling it from top and bottom with a walking foot, it lifts up off the fabric while the feed dogs pull it through, then as the needle goes down into the fabric, it has little grippers underneath that holds it all still. I love mine!

    • I’d never heard of the knit foot, Linda! Do you find that it works better than the walking foot? I am absolutely in love with the walking foot, so for me it’s hard to beat it, but I’m very curious now about this knit foot! Thanks for the tip!

      • I’m lazy when it comes to sewing so my biggest preference for it is that it’s probably equally as good but it’s a snap on foot as opposed to faffing around trying to find my screwdriver for the walking foot!

        This is what it looks like – http://www.sewingbeefabrics.co.uk/shop/low-shank-knit-foot/

        I’ll have to do a side by side comparison at some point and see if there is actually any difference in the amount of stretch / distortion that you get with both of the feet. I would imagine it would be more obvious on some of the lycra costume or swimwear fabrics as they tend to slip about more than cotton knits. I’ll have a hunt for some scraps and see if I can do it for you next week. Give me a prod if I don’t get back to you on it!

  2. Hi! I’m using a pattern that calls for stretch fabric. It has a neckline pattern piece but I didn’t use it because I thought I could just serge the edge and fold over to hem. Needless to say, the neck of the shirt was stretched and would not lay flat. Which is the best method to use to prevent that from happening again? Besides using the pattern piece…thanks

    • Hi. I did 3 courses with KnitWit some years ago.
      We learnt how to put Chanel trim on neckline. It looks neat and classy and
      Works well with stretch fabric.
      You cut a strip of stretch fabric with the stretch running LENGTHWAYS.
      Make it about 3 to 4 times the width of the final width you want. Pin it at the edge right sides facing, to secure it, then sew and gently holding the strip behind and in front ,stretching it slightly as it feeds under the foot.
      (It is pinned at the open shoulder seam just to start. Not pinned along neckline, )
      Turn the strip to the inside, enfolding the neck edge.
      Now .. stitch on the RIGHT side in the crease. Stitching in the ditch. Trim away the excess strip.
      Now sew up your shoulder seam.

  3. I am looking to buy some inexpensive knit fabrics to practice different techniques on and to learn to sew knits with, prior to trying a garment. What knit fabric type would you suggest? There are so many different types that it’s a bit overwhelming, and some are expensive! Thank you!

    • Hello, Andrea, I would say to just go to a big chain store (for example, Joann in the United States) and purchase inexpensive jersey or interlock. The one thing I really suggest is that you make sure to purchase fabric with the same direction and amount of stretch as what you will need for your final garment. And while in the store, just take a bit of time feeling the difference between different types of knit fabrics, because they have different weights, stretches and other qualities, so it’s good to get familiar with them!
      Good luck!

      • Thanks! I will run to Joann’s tomorrow and get a few different types to bring home and try out, plus feel all of them.

        I’ve made a pillowcase, curtains, pj pants, a skirt with pockets, and a tunic with tiebacks so far. I feel like I’m ready to try a simple knit project!

  4. I found this information very helpful. I have 4 machines. Will the walking foot be interchangeable with the machines listed here they are 2 singers, 1 dressmaker, and 1 Super Elna that was manufactured in Switzerland?

  5. I found the information very helpful and intend to try it real soon as I am making some long sleeve tops for winter out of knit. I am finding this web site very informative on crafts as well on the sewing. I started sewing when I was in high school and have continued to sew ever since. Thanks for all the useful information. Have A Nice Day

  6. Love reading these comments but couldn’t find any info I am looking for –
    today after sewing one seam in my knit maxi skirt, I discovered that the stitches were horrible looking, some short ones and some longer ones!
    Someone please tell me why? What do I need to do? Thanks,

    • Hi, Cathy, Those are skipped stitches! Some of them look long because one or more stitches didn’t catch properly and therfore “skip”. I suggest using a different needle and/or thread. Make sure you are using a stretch or jersey needle. And use a different thread type, from a different brand or made from a different fiber. Good luck!

    • It depends what type of stitch you’re using, Cherryl. For a zig zag or other stretch stitch, it’s really not that important. If you’re using a straight stitch for whatever reason, keep the length long!

  7. I enjoyed your post very much! I learned a few things!
    Knits do not fray, that is true, but they can run (like your nylon tights) if pulled on the weft/horizontal cut. They can also run if a hole is put in them. This happens more in lighter weight knits like T-shirt or Lycra. I think most seams need to be finished in some way, but everything is dependent on use!

  8. Thank you for the great information! I’m just starting to sew with knits and I have a question. My project is a knit baby pants, and the pattern calls for rib knit for the leg bands. I’m wondering if I could use the same fabric as the pants for the leg bands instead of the rib knit?

    • You can, as long as they’re not relatively tight cuffs, though rib knit is generally more stretchy, so preferable. Just make sure that the knit fabric that you’re using has at least 5% elastane/spandex/lycra and a good recovery (so that it pulls back into shape). If the leg bands are supposed to be quite snug, though, I would stick with rib knit. Good luck!

  9. Hello, I have learned a lot from you, unfortunately I wish I would have read your article before sewing school clothes for my grandchildren. I have not sewn with knits before, but what I read from other sources I should purchase fabric with at least 5% spandex, which I did. I ordered from different places online and got mostly 95% cotton and 5% spandex knit with most being a 4 way stretch. I sewed the garments together with a zig zag stitch and used a long straight topstitch on the hem and sleeves. I laid the pattern out on the fabric the same way as if it was woven material. (I think that was not the correct thing to do, not sure) I did okay on not having wavy seams. After sewing the first couple of tops I tried them on the grandchildren. The top stitching around the collar broke immediately. Ugh. I redid the collars by cutting them on the bias instead of going across the top of the fabric like the instructions said and did not top stitch. That seamed to fix the problem. I’m not sure what the collars will look like after they are washed however. I then sewed 14 pants and 16 tops. The children wore them the first two days of school and one of the pants had tore out in the seat. Oh no, is that going to happen to all of them?? After reading this article I see I did a few things wrong. I used a universal needle, I assume it is not a ball point one as it did not say. I think I should have cut the collar going with the greatest stretch instead of on the bias. Also, not sure if I laid the pattern out correctly. It just seemed wrong to lay it differently than you would a woven pattern. At this point I am just sitting back waiting to see how many pants split out! Is there anyway I can fix them so they won’t split out?

    • Hi Judy, great questions, and you are not alone in asking them.
      — Patterns get cut out like normal patterns on woven fabric. If there’s an arrow showing the direction of greatest stretch, you have to position it so that it points in the directions where the fabric stretches the most. In 2-way stretch, that’s selvage to selvage, but in 4 way stretch it could be in the other direction..
      — Yes, 4-way stretch fabric is often 95% cotton and 5% spandex, and that is my favorite mix because it feels natural, but has good stretch. Do be aware, though, that not all fabrics have the same type of stretch. Do check out the link that I shared to a post explaining recovery.
      — Collars and cuffs don’t get cut on the bias, but in direction of the greatest stretch. Because the fabric already is stretchy, there’s no need to cut on the bias. Bias gives a small amount of stretch to woven fabric, which is why it’s done that way for woven collars.
      — Universal needles are sharper than stretch or ballpoint needles, and they can pierce the fibers, weakening them and leading to holes in the fabric. Stretch needles have a rounded end which can slip between fibers so that they don’t get damaged.
      — Don’t use a straight stitch, especially not in parts that will get stretched, as necklines will when you pull them over the head. I suggest using the twin needle (https://www.cucicucicoo.com/2019/04/tutorial-how-to-sew-knits-with-a-twin-needle/) or the zig zag or other stretch stitch.
      –Did you sew the seats of the pants with a zig zag stitch? It might be that the pattern didn’t give enough space for the bum. Look at this post on adjusting a pattern’s crotch curve and see if it helps (https://www.cucicucicoo.com/2019/04/how-to-adjust-the-crotch-in-pants/) .

      I hope that answers your questions! Good luck!

  10. I don’t have access to a sewing machine right now, so I am doing hand sewing. Do you have any tips for how to hand sew knit fabric? I want to add pockets to my t-shirts.


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