Approaches to Sewing Knits

Since we’re talking about sewing the Renfrew Top out of knit fabric, and there are all kinds of fabric-related questions that come up about knit fabrics, I’d like to recommend this book, Claire Shaeffer’s Fabric Sewing Guide by Claire Shaeffer. This book is a great resource for answering the question ‘How do I work with this fabric?’

She talks about matching fabric to pattern, planning the garment to get the most out of the fabric’s natural properties. Pressing, needle recommendations and stitch length are all covered.

Of all the sewing books on my shelf, this is the one I refer to most often. Often it’s to confirm what I suspected, or to see if my planned choices are correct before proceeding. It also helps identify fabrics in your collection – do you have a double knit, or an interlock knit? This book will help you know the difference!

Also, before I start posting how I sewed the most recent Renfrew Top, I thought I would talk about my approach to sewing knits. Otherwise, you might have a lot of questions as to why I did certain things!

Plus, if you decide on a general approach to sewing knits before you start, it’s a lot easier to work through the project.You’ll have already decided how to sew each seam, what stitch to use, and what machine to use (serger vs. straight stitch) for each stage. Planning it out beforehand saves time as you sew!

My approach to sewing knits

I tend to treat knits as wovens, almost. I like to sew the seams first, then serge them. You don’t have to do this, you’ll see inside your purchased tee shirts than the seams will be serged only. This creates a stretchy seam that’s fast to sew (just one pass through the machine!) and the edges are finished all in one step.

But I like the extra security of having a seam, and the serging separate. Both seams have to break before I have to mend the shirt, which is good in my books. I like durability in my clothing. You might not want to sew your knit tops this way, and that’s all right too! I thought I’d talk about why I’ve done it a certain way now, rather than each time I talk about a sewing step.

I don’t have a coverstitch machine or the option to convert my serger to a coverstitch. Personally, I don’t desire a coverstitch option. I’m not a fan of any hem that can come completely undone and unfinished with one loose thread. (Ever had the hems come down on a store-bought top? It’s a pain to re-stitch that unfinished edge!)

I like the look of zigzag stitching. I know, I know! You might not agree. Many of you have commented that visible zigzag stitching looks homemade. I suppose that’s because in factories, their straight-stitch machines can only straight-stitch. In order to sew a zigzag, they have to move to a completely separate machine. The garment would have to be passed to a second operator to sew the zigzag stitch, then back to straight stitching (or serging.) It’s not cost-effective to have zigzagged stitching in a factory setting, unless the factory does a lot of volume in zigzag-stitched garments. So that’s likely why we don’t see it in store-bought clothing. It’s truly a mark of a home-sewn garment. (Is that really so bad, or is just that we’re so used to seeing factory-sewn clothing that anything else looks unusual to us now?)

There are plenty of options to the zigzag stitch – basically, any decorative stitch that stretches will work! We’ll talk about that when we get to that part of the sewing instructions.

I do switch to a proper needle for sewing knits. I use a ballpoint needle or a needle marked ‘Jersey’ – these needles are designed to poke through the knit loops of your fabric, rather than pierce them or puncture the fabric. (Imagine poking a pencil through a sweater, dividing the loops to get through to the other side, rather than poking a sweater with a sharp skewer, which could pierce the yarns, weakening them, potentially causing holes. That’s the general concept of using a ballpoint needle!)

Your approach to sewing knits?

Your turn! Tell me how you approach sewing knits. How do you feel about zigzag stitch? Do you trust the strength of a serged-only seam? Is there a book that really helped you sew confidently with knit fabrics?

Here are more blog posts about the Renfrew Top. (Get the pattern here.)

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40 Responses to Approaches to Sewing Knits

  1. Eirian October 31, 2012 at 6:18 am #

    Only recently converted to sewing knits (it was the Refrew what done it), but generally I sew ‘difficult’ seams, so the neckline, the shoulders and attaching the sleeves, and just serge the side seams and the bands. I very rarely topstitch, but when I do, I use my stretch stitch rather than a zig zag. I do switch my sewing machine and serger to ballpoint needles after some sad-making holes in serged seams. One thing I love about serging rather than sewing, is that the differential feed on my serger means that flimsy jersey doesn’t go wavy and stretched out. I bought a book on serging (Sewing with Sergers), but mostly it’s been trial, error and sewing blogs. And the lovely Renfrew! Did you know that you can get one and a half Renfrews from 2m of Jersey? My three year old looks awesome in her mini-Renfrew. She particularly loves the cowl neck :)

  2. June October 31, 2012 at 6:51 am #

    I agree (in principle) about not wanting hems that can come undone as fast as a zipper. However, after purchasing and getting to know my coverstitch and blind hemmer, I’ve learned that if you properly end the seam, it doesn’t come out. I know this very well because I’ve hemmed things poorly on the first pass and wanted to redo, and it was a major, major pain to take out the hem.

    (For those who want to know how to end coverstitch – go to For those who want to know how to end a blind hemmer stitch, mine is a curved-needle model, I swing the needle as far to the left as it can go, lower the feed, hold the fabric where the last stitch was [as close as possible to that point], and yank the fabric out hard enough to break the thread.)

    Some sergers can do a “safety” stitch with 5 threads, my understanding is that it’s a 4-thread serged seam with the 5th thread making a chain stitch on the inside of that. It’s sort of similar to your sewn seam plus overlocked edge, except that a chain stitch can be “unzipped.” But it’s done in a single pass on 1 machine.

  3. Amanda October 31, 2012 at 6:59 am #

    Very interesting! I agree with you that zig zag stitching likely looks homemade to many because we compare it to RTW. I can’t say I’ve ever had a seam break on me or a hem come down in my store-bought knit garments though. I’ve had one knit tee for 10 years now and it’s just started to get holes in the fabric. So I guess that just gives me the confidence to only use my serger/overlocker for joining knit pieces. I have to admit it’s a nice time saver since sewing time can be minimal for me!

  4. Linda October 31, 2012 at 7:01 am #

    I think you covered knits well. I might add that pre-washing is imperative. I purchased a beautiful not so cheap knit intended to make a long sleeve Renfrew and had to use the 3/4 length sleeve view because the fabric shrunk more than I anticipated. Thankfully I also love that view. I love zig zag…it is used by Dior used it in some of his creations referenced in the latest article by Claire in Threads Magazine….serging is a no-no in couture but great for casual knits…I do sew first as you do.

  5. Sabs October 31, 2012 at 7:07 am #

    I’ve just started to sew my very first top with a jersey knit fabric. Unfortunately it’s not the Renfrew (altho that’s on my list!) Your tips have been really useful – I had absolutely no idea how to tackle knits initially and bought the fabric just because I liked the colour and it was a bargain for £1/m! I thought I’d try making a long sleeved Tshirt and maybe a couple of pairs of knickers from the leftovers! So far I’ve used the knit straight stitch on my machine (again first time ever!) and am planning to zig zag the seams. I don’t think zig zags are too homemade at all, in fact they add a decorative touch in my opinion!

  6. Marlise October 31, 2012 at 7:09 am #

    Hi Tasia,
    I sew all my knit tops and dresses with my sewing machine – I don´t own a serger. I use a stitch that is referred to as overlock stitch. It´s basically a zigzag stitch followed by two straight stitches and the result is a seam that can be stetched quite a bit. I usually use a twin needle to finish the hem. No visible zigzag stitches until now, however;-) But I remember a guy in a blue t-shirt recently with the side seams “reinforced” by red zigzag stitches – it looked pretty cool as a design element and I will probably try this on a top in the future.

  7. CGCouture October 31, 2012 at 9:14 am #

    I just use the serger on knits, but, if something is exceptionally tight, the threads can show through, so your method probably would work best for garments (and sections) that get extra strain. I’ve been known to use a regular sewing machine to reinforce areas of strain. I don’t have a coverstitch either, I use a twin needle. After learning that you need to loosen the upper tensions significantly to prevent tunneling + use interfacing on the hems (I love the SewKeysE rolls of knit interfacing for this), I’ve been much happier with my results. If it helps, I set my Pfaff’s upper tension at about 1.5-2, but it really depends on how tight your machine stitches regularly–mine stays at about 4-4.5 on typical seams.

  8. Amanda October 31, 2012 at 9:52 am #

    I am pretty new to sewing knits and have so enjoyed all your posts on Renfrew. I find that depending on what I’m sewing (or planning) I pay attention to different things in RTW clothes. Recently, I noticed that almost all my undergarments use zig zag stitching (and they are all RTW items). Just like this tutorial I came across recently.

    • Tasia October 31, 2012 at 10:31 am #

      Oh, me too! When I’m thinking about coats, I check out everyone’s coats on the street and pay closer attention to my own wardrobe. It’s interesting how that just naturally happens!
      I’ve noticed zigzag on some of my underwear, too, after we talked about sewing underwear recently! I’ve also started thinking about details on my underwear that I dislike (metal adornments) and details I do like (flattering seaming and bows).
      So glad you’ve enjoyed the Renfrew posts so far!

      • Thea October 31, 2012 at 11:24 am #

        I do the same thing – I think people find me odd on public transport. I’m recently either knitting, or checking out everybody’s garments (and you’re not supposed to look at people on the tube in London!). I once had an epiphany when I was thinking about lining a jacket on the tube, and just started inspecting my sleeve hems and the overall hem very closely. And I also noticed a while ago that a lot of my underwear is zigzagged. Which gives me hope for making some at some point, as I don’t own a serger! And from me, too, thanks for the Renfrew posts – I’m gaining confidence, and they’re moving up on the to-do list!

  9. Gemma October 31, 2012 at 10:08 am #

    Do you sew the seams using a straight stitch (and slightly stretching the fabric as you go) or a narrow zig-zag? Or a special stretch stitch? I use a narrow zig zag as I worry I’ll over-stretch the fabric if I use a straight stitch and the stretch stitch on my machine is awful to rip out if I make a mistake. The zig zag works fine though.

    As for hems, I use a twin needle and it looks great. I like the look of the wide zig zag too though.

    Do you use Stretch needles at all? I use them for jerseys (or stretch wovens) with lycra in them but I assume I could use a ballpoint needle too….?

    I adore the colour of your jersey by the way, can’t wait to see your top all finished!

    • Tasia October 31, 2012 at 10:25 am #

      I’m sewing the seams this time with a stretch stitch, the triple-stitch setting on my machine. It is terrible to rip out, you’re right. I only do that if the seam is going to be stretched though. For something like the shoulder seams, where I’m going to be reinforcing the seam to remove the stretch, I wouldn’t bother using a stretchy stitch and just use a regular stitch.

      I like the idea of a twin needle, but never get around to setting it up or using it. One day I will! (Mostly so I can write about it.)

      I tend to pick the ballpoint needles because that’s what I have and they’ve worked well for me. Here’s a good discussion on PatternReview about the difference between stretch and ballpoint needles –

  10. funnygrrl October 31, 2012 at 10:14 am #

    I started sewing with knits before I realized that it could be difficult. Ignorance is bliss! Some seams I sew and then serge. Others I go straight to the serger. Just depends on the garment and seam.
    I used to zigzag before I bought my serger. I don’t understand how it looks homesewn…and how that could be negative.

    • Tasia October 31, 2012 at 10:20 am #

      I think people mean zigzag on the outside of the garment, where it’s visible. Zigzag on the inside is our secret!

      A lot of people approach knit sewing the same way – fearlessly, because you haven’t read anything telling you it’s supposed to be hard! It really isn’t, it’s just so different from sewing wovens, if you’ve spent a lot of time sewing wovens and feel really comfortable sewing fabrics that don’t stretch or move on you. Or if you hear a lot of people telling you knits are hard, and you haven’t tried them, it’s easy to get a mental block about sewing knit fabrics. Sometimes the fearless approach is the best way – you’re getting in there and trying it out, before you’ve had time to form any fears.

  11. Erin October 31, 2012 at 10:43 am #

    I’ve been a big hater of the zig zag in the past favoring a twin needle until recently. I’ve rediscovered the zig zag, and sometimes it just works better than anything else. I love it now.

  12. Lisa October 31, 2012 at 10:48 am #

    I am slowly getting better at sewing knits. I do one run through My serger and depending on the pattern I will use my double needle or create a banded bottom and sleeves (like your renfrew tops). For my neckbands I stop following most manufactures pieces and I just cut one really long piece that I pin and stretch to the neckband. Before I sew it on I cut it to the right size, sew it together and then attach it to the neckband. My new method takes a bit longerbut gives me the results I like.

  13. Latrice October 31, 2012 at 11:17 am #

    I am not 100% comfortable with the serger being the only seem. I am last renfrew was made that way and I just don’t think it is as good as the one that I made where I used the serger and a narrow zigzag stitch and even the one I just made a narrow zigzag.

    I find that necklines are the trickiest to master when it comes to sewing with knits.

    • Tasia October 31, 2012 at 2:31 pm #

      Nice to know I’m not the only one that likes their seams to be stronger than serged only!
      I agree, necklines are tricky. Probably the most important part as well as the hardest, as they’re right in front, where everyone will see if you make a mistake!

  14. Tasha October 31, 2012 at 11:34 am #

    Do you ever use a walking foot for knits? I don’t have a serger, so I tend to use a zigzag of various lengths and widths for seams, depending on how much it needs to stretch. I find my walking foot helps out quite a bit keeping the fabric from getting stretched out as I sew.

    • Tasia October 31, 2012 at 2:29 pm #

      No, I haven’t used a walking foot before. I feel like my fabric goes under the foot pretty well without being stretched out – though if I tried a walking foot I might be pleasantly surprised! I don’t sew a lot of knits, and trying to buy a new foot for my machine seems like a lot of work unless I started to sew a lot of knit fabrics. Which I might at some point!
      Good to know it helps a lot in working with knits!

      • PerlenDiva November 1, 2012 at 6:43 am #

        Tasia, doesn’t your Pfaff have IDT? This is like a walking foot. I leave it in whenever possible, it doesn’t work with some feet, though.

  15. Nancy Schaub October 31, 2012 at 12:00 pm #

    I have avoided knits like the plague because I do not particularly like the look of a serged seam. I do not have a serger so when I made knit pajamas for my grandchildren, I used the interlock stitch, as mentioned above. I suppose I may need to get a serger if I want to make my own knit slacks. I will save your tips as they make a lot of sense. I have had the double row of stitching on hemlines pop if I happen to pull in the hem to try to get a little more room out of a top after washing seems to shrink it down just a little. I do repair those with twin needles. Sometimes I think I will just make a bunch of woven tunics and use Seams Great on the raw edges. I am learning a lot from all the sewing blogs I have started to follow. Thanks for the tips.

  16. Julie October 31, 2012 at 12:32 pm #

    I don’t have a serger so I sew the seams with a small zigzag stitch, then finish the seams with a closed overlock stitch. I have made three of the scoop necked long sleeved Renfrew tops and the top stitching was done with the honeycombe stitch which looks quite decorative.

  17. Nancy Schaub October 31, 2012 at 12:36 pm #

    Your patterns are lovely. Do any come in plus size?

    • Tasia October 31, 2012 at 12:41 pm #

      Hi Nancy, thank you! At this point no, I don’t have plus sizes. I don’t know enough about fitting a plus-size figure to do a good job with the patterns! I wish it was as simple as just scaling them up, but I know it’s not. Here’s a link to the size chart – – the sizes are closer to modern ready-to-wear sizing than commercial pattern sizing. I’m good at designing for pear-shapes, so that’s what I stick to for now!

  18. Sue October 31, 2012 at 1:47 pm #

    I have the book Claire Shaeffer’s Fabric Sewing Guide by Claire Shaeffer. It is my fabric bible. It has given me the information I need to sew all kinds of fabrics with confidence. I would strongly recommend all serious sewers to get one!

    • Tasia October 31, 2012 at 2:09 pm #

      I totally agree! It’s a thorough, comprehensive, heavy book packed with everything you ever wanted to know about fabric, and then some.

  19. Becky October 31, 2012 at 2:02 pm #

    I tend to do the opposite of you– I’ll serge a seam first, and then sew it if I think it needs reinforcement! For some reason, the seams tend to ripple less when I do it that way.

    And I agree that resewing those hems on t-shirts is a pain. I usually just serge the hem, then turn it up and stitch it.

  20. Rachel October 31, 2012 at 2:10 pm #

    i have to admit, i love the look of zigzag stitch on my sewn clothing b/c to me it’s mark of a homemade and hopefully high quality garment … i don’t think most people look that closely anyways – only people who also make their own stuff would know the significance of a different stitch :)

    • Tasia October 31, 2012 at 4:09 pm #

      That is a good point – most people who read here are people who sew, so I’d have to ask some non-sewing people what they think! You’re probably right, it’s only us that notice the zigzag look, unless it’s done as a detail in contrast thread or something intentional.

  21. Jacinta October 31, 2012 at 3:15 pm #

    Great timing as I just borrowed that book from my library yesterday as they didn’t have any other decent sewing books available. I’m glad this one is a winner then!! :)

    • Tasia October 31, 2012 at 4:05 pm #

      It’s an excellent reference book and a good way to learn about different fabrics. Especially if you’re planning to work with new-to-you fabrics, or something extra special. Nice that your library had a copy!

  22. kaitui_kiwi October 31, 2012 at 5:34 pm #

    Sometimes I straight stitch then three-thread overlock my seams on knits or I skip the sewing machine altogether and just four-thread overlock them because it is fast.

    I recently make my husband a top out of a merino knit blend and to make it look more professional I top stitched using my sewing machines faux-overlock stitch – it’s like a zig zag between two lines to straight stitching – it looks really professional, like a cover stitch finish, he was chuffed with it – I have some pictures here:

  23. Inna October 31, 2012 at 6:11 pm #

    I also refer to Claire Shaeffer’s books a lot, it’s one of my favorites! Last week, I purchased the Craftsy class “Sewing With Knits” by Meg McElwee and I recommend this class to everyone who still has some doubts about knits. It definitely changed the way I work with knits!

  24. Sara October 31, 2012 at 11:27 pm #

    I love the look of a zigzag stitch! I use it confidently to finish my hems and my seams. I don’t have a serger and I’ve heard they’re a pain in the butt to thread and adjust the tensions on them. I hate learning a new machine and it’s just not worth it to me. I’ll stick to my zigzag, thanks. I didn’t realize that hems done on a coverstitch machine can come apart like that – now I have another reason for not wanting one of those too.

  25. PerlenDiva November 1, 2012 at 6:33 am #

    If I’m sure about the fit, I just serge the seams- those two needle threads do give you a double seam, after all – if I’m not: a seam from a normal machine is so much easier to take out. Plus: you still have the seam allowance for adjustments ;-)
    I’m not so keen on zigzag showing on the outside, but I’ve seen examples of other pretty decorative stitches, eg loops or waves, used for topstitching and hems. I certainly want to give these a try cause it says “customized” and “created with care” rather than “home-made” to me.
    Happy Sewing

  26. Tatiana November 1, 2012 at 11:35 am #

    I am still learning how to sew, but I absolutely love to sew with knits! I live in Brazil, and we have a prettu relaxed dress code most of the time, so we ALL wear knits all the time! Also, I find it easier to deal with a knit than with a woven fabric, your mistakes on knits are not that visible. Like you, Tasia, I like the look of the zigzag stitch. It was actually funny you saying that people think this looks homemade, because in here is the opposite. When I went to my sewing course wearing my Tie-Dye pink Renfrew, they all (teacher includind) loved the zig-zag topstiching detail on the neck, they told me that this made the top look really professional! I already made three Renfrews, all different, and I absolutely love this pattern! I am looking forward to sew Tiramisu from 3hourspast…

    Thanks for your amazing patterns! Next, Cambie!

  27. Kiley November 5, 2013 at 8:24 am #

    What am I doing wrong if my stitches are coming undone in the hems of my leggings after just one wash? Any ideas?


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