Although hugely popular in ready-to-wear and more, knit fabrics tend to have a bad reputation among home sewing enthusiasts. Poor little knits! All too often, that bad rap comes from false information, or a complete lack of knowledge about the category. We promised our knit friends we’d tell their story and help clear their names. To know knits is to love them! Plus, our current Oh Baby! series with Fabric.com uses a number of pretty knits, because soft knits and soft babies are a natural pair.
Fabric.com carries a wonderfully wide variety of knits. Carve out a little time to browse online through all the categories: from designer knits to thermals to jersey and more. They also have some of their own articles with knit sewing and preparation tips. Our thanks to all our friends at Fabric.com for sponsoring our Oh Baby! series and providing such great shopping inspiration every day of the year.
This article focuses solely on sewing knits with a sewing machine. In mass production, knit fabrics are traditionally sewn on a serger (also known as an overlock machine). These machines are specifically designed to sew knit fabrics so the stitches stretch with the stretch of the fabric. Since not everyone has a serger in his/her budget, we have collected the top tips, techniques and tools that allow you to use your sewing machine instead. Most models can produce a stretch stitch of one kind or another that will act similarly to the overlock stitch on a serger.
Nothin' but knit
We will give you the basics today, but if you want to become a true knit expert (okay... we have to say it: a Knit Wit), we encourage you to purchase a fabric reference guide, use the Internet, and ask questions of your local fabric store staff. Each will help you build your knowledge exponentially. It’s always a good idea to get to know the fabric you plan to use, and knit fabrics really are a world of their own. They’re available in all types of colors, weights, textures, fiber content, and degrees of stretchiness. The choices are virtually endless!
In previous tutorials, we’ve mentioned the importance of working with quality supplies. When we say quality, we mean the best your budget will allow. Purchasing good quality knit fabric is no different.
Before we get into the actual sewing techniques for knits, let’s discuss some of the details about knit fabrics: how they’re made, as well as the main categories and types. Sound boring? It’s actually very interesting, and the better you understand things, the less scary that knit aisle will be the next time you venture in.
Warp and weft
Knit fabrics are produced using two methods: warp and weft. Warp knits are made with many yarns, which move vertically, and one warp stitch.
Weft knits are made with one yarn and one single stitch, or a combination of stitches (plain, purl or rib). If you’ve ever tried hand knitting, some of this may sound familiar to you. A basic knit stitch in hand knitting is a weft knit.
It’s the warp or weft method, along with the fiber content, that dictates the amount of stretch in a knit fabric.
Knits are put into three main categories based on the amount of stretch.
Stable Knits: These knits have limited stretch, but more movement than a woven fabric. You can use similar sewing techniques to those you'd use for standard woven fabrics.
Stretchable Knits: Similar to Grandma’s hand knitted items, these have more stretch in one direction than the other (usually from edge to edge) and do require specific sewing techniques.
Two-Way Stretchable Knits: These are the knits we love to wear! They stretch in both directions – across the fabric and down the length. Swim suits and exercise wear are made from knits in this category.
NOTE: There’s also something known as a Four-Way Stretchable Knit. The difference relates to specific production methods we won't go into here. Rest assured, both are really stretchy knits.
Below is a list of some of the knits you probably have in your closet and around your home. Of course, this isn't a comprehensive inventory; there are certainly more types available. As we mentioned above, should you become a Knit Wit, you can write in and give us an advanced tutorial on some of the specialty knits. Until then, we'll deal with the most common variaties.
Jersey: This is the soft "T-shirt type" knit we adore. It has a distinct right and wrong side, which you can tell by the direction in which the fabric curls at the edge; it always goes toward the right side.
Double knit: The same on both sides, it has minimal stretch and retains its shape well.
Interlock: A lightweight, very drape-able knit. (We’ll be sewing with it later in this tutorial.)
Rib knit: You’re probably most familiar with this one as the knit fabric used around T-shirt necklines.
Stretch Terry: Looks like a towel, little loops and all, but has stretch.
Stretch Velour: If you grew up in the 70s, you probably had a pantsuit made out of this (maybe two)!
Stretch Velvet: You can always tell velvet by its shine, but this kind has shine and stretch.
Sweater knit: This one is fairly easy to identify; it looks like a sweater but is on the bolt instead of your back.
Sweatshirt knit: Another fave! This thicker knit is soft and comfy year 'round.
Tricot: You probably have something made of this in your fine lingerie drawer.
Action: Where would we be without this type of knit? We'd have nothing to wear to the gym.
Other tidbits about knits
Knit fabrics can stretch anywhere from 20% to 75%. The stretch will dictate exactly what you can make out of it. In addition to the degree of stretchiness, there’s also the direction of stretch to consider.
Depending on the type of knit fabric you’ve selected, it may have a right and wrong side. Or, like your T-shirt, it can be the same on both sides.
Finding the grainline on a knit can be a bit of challenge due to its "movability" on the cutting table (we’ll talk more about this in the next section). Where you find the greatest amount of stretch is the grainline of a knit fabric.
In home décor sewing, "ease" is not something your normally worry about. However, we wear knit fabrics because they are so comfortable and move with our body. If you choose to sew a garment from a knit fabric, remember the stretch of the knit is the "ease." When sewing with woven fabric, you have to build in "ease" to be able to move comfortably in a garment. With knits, you simply don’t have to worry about this. This is also why fitting is not as much of an issue either.
Whether made of natural fiber, synthetic fiber, or a combination of both (just like their woven counterparts), knits are available in various weights, from extremely delicate to quite heavy. You will have to adjust your machine settings, needle size, and thread type to correspond with the weight with which you are working.
Most knits do not require a seam finish, but sewn projects always look more professional when they're finished on the raw edge. Plus, just like pantyhose (also a knit), many knits can run. Finishing the raw edges helps avoid this problem.
Learning how to properly cut knit fabric is a must! That statement isn't meant to scare you, but rather to make you aware it’s really, really important!
If you’ve ever cut fabric with a nap, such as velvet or corduroy, you may have learned the hard way that you have to cut the pattern pieces in the same direction. Otherwise, the fabric will have a different color appearance because of the nap of the fabric. For example, if you cut a skirt front with the waist facing up, and the skirt back with the waist facing in the opposite direction, your skirt will appear to be two different colors front and back! Cutting knits creates a similar scenario because of the stretch. If using a comericial pattern, follow the “with nap” layout. This ensures your finished project stretches in the right direction when finished.
Always cut knit fabric on a large flat surface, making sure it does not hang off the edge. It can become distorted as well as stretch out of shape, causing you to have cut misshapen pieces.
Securing pattern pieces in place is equally important on knit fabrics in order to eliminate bunching or moving of the knit fabric on the flat surface. Use the proper type of pins. Sharp pins can damage a knit’s weave. Instead, use ballpoint pins, which are rounded at the top and slide between the loops of the knit.
You can use pattern weightsto hold pattern pieces in place.
As for actual cutting, you must use very sharp scissors or a rotary cutter. Remember, some knits are more delicate than others; be precise and move slowly as you cut around each piece.
All markings should be done with chalk or a fabric marking pen or pencil. If you’re accustomed to clipping into the fabric, cut notch points rather than a simple straight snip. This helps prevent runs.
Sewing machine supplies
Another word of caution: if you do not use the recommended sewing machine needle type, size, thread, and foot for the knit fabric you’re sewing, you will have a very bad experience. The fact that knit fabric has a bad rap is probably because these important steps were skipped, or maybe not understood at all!
As we mentioned in the previous section about straight pins, you must also use a Ballpoint needle. Depending on the weight and type of knit you’re planning to sew, you will also have to consider the size of the ballpoint needle. In addition, there’s a Stretch needle that is recommended for use with those super stretchy knits, such as swimwear.
In addition to the single needles mentioned above, it’s also recommended to use a twin needle to sew knits on a sewing machine. When you use a twin needle, you use two spools of thread and one bobbin. As you sew, two parallel lines of straight stitches are formed with a zigzag underneath. The zig zag underneath gives you stretch for your stretch fabric.
Believe it or not, this area is pretty basic. For knits, use all-purpose polyester or cotton covered polyester thread. The polyester content allows for stretch.
Sewing Machine Feet
We’ve gathered our favorite sewing machine feet for sewing knit fabrics. By no means do you have to own all of them, but there are a couple well worth the investment. Be sure to visit your local sewing machine retailer for the complete selection of feet designed to work with knit fabrics for your make/model. Depending on the exact type of knit, one of these feet may be a better choice than another. Overall, it’s recommended you use an Even Feed or Walking foot with knits.
A. Standard foot This is the basic foot that comes on your machine at the time of purchase.
B. Even Feed foot Also known as a Walking foot. The additional set of feed dogs on the foot helps to evenly feed two layers of fabric under the needle. Since knits stretch and move a lot, this is the ideal foot to keep everything even as you sew.
C. Rotary Even foot The little tracks on this foot act similar to the extra feed dogs on the Even Feed foot. Again, the idea of using this foot is to keep those pesky knit layers even.
D. Tricot foot If you’re sewing with a very lightweight knit, like tricot, you can give this foot a try.
E. Straight Stitch foot and Straight Stitch Needle Plate This combination is a good idea for any lightweight fabrics (woven or knit). Remember though, you can’t use a twin needle with this foot and needle plate!
As we discussed earlier, knits require no seam finish because they do not ravel. However, they are bulky and tend to curl. So, the traditional suggestion is to add a second row of stitching about ¼” from your seam, then trim away the excess close to this second row
Most raw edges on knits where there is no seam are finished with a single fold hem and topstitching, but there are times when a blind hem is in order. In these cases, you’ll need a Blind Hem foot (F).
We’re fortunate to have Janome as our exclusive sewing machine sponsor here at Sew4Home. They provide us with wonderful sewing machines that sew knit fabrics with ease due to their Superior Feed System (or SFS). If you’re ready for a new sewing machine visit their website to learn more.
There are a few other items you may want to have on hand when sewing with knits. Similar to sewing with other fabric types, areas of stress are important to reinforce. This may require interfacing. Look for interfacing specific to knits, such as Pellon’s Easy-Knit® Fusible Tricot.
You may have noticed a clear tape in the shoulder and waist seams of knit garments you own. This is necessary for high stress points.
The next time you’re at your local fabric shop or online, look for Stay Tape, Twill Tape, and/or Clear Elastic.
Your main objective when sewing a knit fabric with your sewing machine is to keep the seams flat. Knit fabric tends to fight itself under the pressure of the foot. If you try to sew it like regular fabric, it does one of two things: 1) goes nowhere and jams up under the needle plate, or 2) stretches as you sew and becomes highly distorted. Don’t let this scare you; think about all you’ve learned already! You have most of the information you need to sew knit fabric successfully with your sewing machine. All we need to do is make proper stitch selections and a few minor adjustments.
NOTE: In our stitch examples below, we are showing a variety of stitches available on the Janome machines in our Sew4Home studios. It’s important you take the time to familiarize yourself with the stitches on your own sewing machine, along with the available feet and how to properly adjust the settings. Your sewing machine retailer is a great resource for this kind of assistance.
Machine set up
- Insert a ballpoint needle (remember, you can also use a twin needle).
- Thread the needle and bobbin with a polyester or cotton covered polyester thread.
- Select a stitch based on whether you are doing construction, finishing the raw edges, or hemming. (See more detail below.)
- Adjust the width and length as needed.
NOTE: If you have limited stitch options, experts all agree that a stitch that is not specifically for knit fabric should be shortened in length. The smaller the stitch, the less likely it is to “pop.”
- Attach the appropriate foot for the stitch selected. (We indicate the foot we use in the examples below for each stitch type)
- If your sewing machine has a Pressure Dial, you want to drop this down to 1 or 1.5, depending on your model. Less pressure from the foot will help the fabric feed evenly as you sew.
- Adjust the needle tension based on your specific make and model. In the Sew4Home studio, the Janome machines we use automatically reduce the tension when we select any of the knit or stretch stitches. Review the recommended settings in your owner’s manual or with your sewing machine retailer.
- Always sew slowly for best results. Again, depending on the type of machine you have, in order for the machine to sew some of the specific knit stitches, it has to move in both a forward and backward motion. Don’t be bossy. Let the machine do the work; do not try to push or pull the fabric.
- If your sewing machine has speed control, lower the speed so you can’t go too fast.
NOTE: As we mentioned above, in our stitching examples, we’re using an interlock knit. Once you have the proper needle and thread in place and have adjusted the pressure dial and tension (as needed for your particular knit)... stop. Grab a scrap and test, test, test the stitch you want to use before starting on your final project!
Zig zag stitch
- As we’ve been discussing, a key element for success with knits is working with the stretch, not against it. Even the most basic sewing machine has a stitch suitable for sewing knits: the zig zag. This stitch allows for some stretch in the seam, which is exactly what we need.
- For the below example, we used an Even Feed (or walking) foot.
- Select the zig zag stitch.
- Adjust to a narrow width and a medium stitch length. We adjusted our width to 2.5 mm and the length to 1.8 mm.
- Some experts find using a wide (5.0+) zigzag stitch is better for knits. The idea is that you can create a similar effect as a serger with a stitch that is approximately ¼” wide, then simply trim away the excess beyond the stitching.
- Some machines have what’s called a stretch (or tricot) stitch. It looks a little like a lightening bolt, and is specifically for sewing knits that pucker. The slight angle of the stitch combined with the small zig zag is what makes it an ideal stitch for knit fabrics. We used the default settings and a standard presser foot. The width is 2.0 and the length is 2.5.
Triple Stretch stitch
- A triple stretch stitch is formed when the machine’s feed dogs move the fabric forward and then backward as the machine sews with a straight stitch. The forward-backward movement gives you stretch, yet it is super durable. Use this stitch at points of stress, such as armholes or the crotch-line.
- You may notice our knit fabric is slightly puckered, that’s because this stitch is generally not used for basic construction. We tested at the default width (3.5) and length (2.5) and used a standard presser foot. However, we adjusted the tension down to 3.8.
- You can use a regular straight stitch, but (oddly enough) this is considered an advanced technique. You have to hold the knit from the front and back of the foot, and feed it through at just the right pace, so you do not stretch the fabric. In addition, a straight stitch, if not shortened in length, has little or no stretch. As a result, the seam will “pop” open at the seams, and your sewn item will probably not last the day.
NOTE: Don’t forget, you can also use a Twin Ballpoint needle and a straight stitch to sew knits as we discussed above. Make sure to adjust your stitch settings and tension accordingly.
- We attached our Even Feed (or walking) foot for the sample below. The stitch length was adjusted to 1.8 mm and the tension was lowered to 3.8 mm.
- As you can see from the photo, we did experience a bit of puckering, which proves why a straight stitch is probably your last resort.
- In case you’re wondering what happens to a straight stitch if you make no adjustments... as soon as you pull on the knit, this is what it will look like:
As we talked about in the introduction to the types of knits, some tend to curl at the edge or are too bulky to leave in the seam. We also mentioned how knits do not necessarily have to be finished on the raw edge as a woven fabric would. But, since we like a professional look on the inside as well as the outside, we encourage you to finish the raw edges of your knit projects.
Once again, a basic zig zag can be used, but check your machine for a stitch (or stitches) similar to the ones we outline below. You will be using a combination of stitches. One is used for actual construction, while the finishing stitch is used along the raw edge and on one layer only.
NOTE: It’s best to sew these stitches in from the raw edge, then trim away the excess making sure you do not clip the stitching.
Multiple zig zag
- We have a multiple zig zag stitch option on our Janome machine. It’s a zig zag stitch formed with multiple steps instead of the needle simply swinging from left to right as it does with a basic zigzag. We used the default settings for our example (width is 5.0 mm and the length is 1.0 mm) and a standard presser foot.
- Below is a look at what this finishing stitch looks like next to our previously sewn stretch stitch seam.
- By its name alone, you know this is a good stitch to use on knits. Much like the triple stretch stitch described above, the feed dogs move the fabric backward and forward as the machine creates the stitch. Anytime a stitch is created with this type of motion it means the stitch will have stretch. More importantly, this specific stitch is designed to be used on one layer of fabric as a finish to the raw edge.
- We used the default stitch settings and a standard foot.
You can leave raw edges unfinished, but as we’ve cautioned, knits can run just like pantyhose, so it’s best to use one of the following hems. Some of the stitches below are basic ones, while others are specific to our Janome models. Be sure to check your machine manual to see which stitches you can use for hemming.
Stretch blind hem
- This stitch sews very similarly to a basic blind hem. You may have already spotted the only difference in the photo below. That’s right! See the small zigzag in between? There’s our favorite stitch again for knits.
- From the front, it looks just like a traditional blind hem. As usual, we used contrasting thread so you could see the stitching; you would use a matching thread.
Visible hem knit stitch
- We found this fun stitch on our Janome machine and thought you might like to see it. It’s called a Visible Hem Knit Stitch. At a quick glance, it reminds us of a coverstitch you’d create on a serger. And, just like a coverstitch, you sew this hem finish from the right side. Then, you trim away the excess beyond the stitching on the wrong side, similar to the finishing steps above.
Single fold hem
- Depending on the width (or girth) of the hem area, you can create a single fold hem and topstitch it in place with a zigzag, stretch, or even a straight stitch (since it’s not a stress point) with or without a twin needle. We chose to use a stretch stitch in our single fold hem example.
- We always like to remind you that preshrinking fabric is a good idea. Some knits shrink more than others, plus they tend to get stretched while stored on the bolt.
- When researching a specific knit, take note of the fiber content shown on the bolt, in case you need to press your fabric.
- If a knit is particularly slippery, you can use a layer of tissue paper under the fabric to help stabilize it as you cut out your pattern pieces. This works for fine woven fabrics too!
- If you don’t have pattern weights, you can use other items from around the house, or simply some large rocks (clean, of course) from the garden.
- Use a large bulletin board under your fabric so you can pin the fabric in place to eliminate movement.
- Cut the length of your knit project, especially garments, 1” longer than necessary. You can straighten the edge later. Otherwise, you may find the knit is uneven at the bottom and there isn’t enough fabric to fix it.
- Always test stitches and settings on scraps first to determine the length, width, etc. Be sure to pull on the seam too, to make sure there will be no “popping” of the seam later.
- If you do not have stay tape on hand to reinforce a seam, you can use a piece of the selvedge edge of the fabric.
- If you’re having trouble sewing a knit, try placing strips of lightweight tearaway stabilizer, or even household wax paper, on top of your fabric and under the needle.
- Let knits hang for 24 hours before hemming.
- You may have noticed that whenever a zipper is inserted into a knit garment, it’s usually a lightweight plastic zipper. That’s because heavier zippers can weigh down the knit.
- If you want to use buttonhole closure on a knit project, some sewing machines have special knit and/or stretch buttonholes.
- Instead of using one of the hemming techniques above, you can cover the raw edges with a knit binding.
- Unloved or unwanted knit items are ideal for repurposing. You’ll find plenty of tutorials on the Internet for quilts, scarves, bags, and more, all made from repurposed t-shirts, sweaters, etc. Here’s a Felted Pillow we made from repurposed sweaters.
Sample Creation and Instructional Outline: Jodi Kelly