Alternate Cable cast-on for 2×1 & 1×2 ribbing

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Following on from my blog post showing how to use the Alternate Cable cast-on for 2 by 2 ribbing, here’s a glimpse at how to tackle cast-ons for both 2 by 1 and 1 by 2 ribbing. When Fiona left a comment asking about these ribs, it got me thinking, and then it got me experimenting.

First things first – just like 2 by 2 wouldn’t work by casting on multiples of 2 knit stitches and then 2 purl stitches, casting on the stitches in a literal manner doesn’t work for 2 by 1 or 1 by 2, either.

The cast on for a 2 by 1 or 1 by 2 rib is virtually the same as that for a 2 by 2 rib, except it has one extra step, performed during that first row when the stitches are juggled from our base 1 by 1.

For this blog post, I won’t start from scratch with the basics of the Alternate Cable cast-on – I’ll direct you to the main tutorial for that.

So, just like before, we’ll start with our 1 by 1 Alternate Cable cast-on. Except this time, you need to cast on one third more stitches than you need. So if you need 60 stitches (a 2 by 1 or 1 by 2 works on a multiple of 3, right?) then you’ll want to be casting on 80 stitches. Which means we’ll always be casting on in a multiple of 4, and that is just how we want it.

As you’ll have noted from the other tutorial, I treat the first slip knot of the cast-on as a purl stitch, and after casting on the required number of stitches (including that first knot), the last stitch cast-on will be a knit stitch. I then work the first row flat, and join after that. It makes the first round sturdier, less likely to twist, and makes a much neater rib, as well as putting a knit stitch at the beginning of the round, which we’re most familiar with.

2 by 1 rib, (knit 2, purl 1)

So let’s start with 2 by 1 rib (knit 2, purl 1), because how we start that very first row is a bit different for each.

Our first flat row: knit the first stitch.
The next stitch we come to is a purl stitch, so before we do anything else, we want to swap that stitch around with the knit stitch following it. Remember to bring the knit stitch via the front when you swap them over, else it’ll go rather pear-shaped.
This bit is the same as the 2 by 2 rib – swapping your stitches like this gets us the paired stitches sitting neatly together, and gives us that wonderful edge to the cast-on. If you’re not sure about this step, I’ll quickly refer you back to the 2 by 2 AC blog post to see this step in more depth.
Then proceed to knit the next stitch….
… then we find ourselves with 2 purl stitches, which is exactly what we should have. And this is where the penny drops – we only want one purl stitch here, seeing as we’re working a knit 2, purl 1 rib, and when we have 2 stitches and only want the first, what do we do? We decrease.
I found that the purl decrease that gave the neatest results was actually a purl 2 stitches together through the backs of the loops. At first I tried a regular purl 2 together, but didn’t like the way the stitches were stacked on the reverse. This might not make much difference to some, but I do like having things look neat on both sides. Then I tried a slip the next 2 stitches knitwise and purl them together through the backs of the loops, but the stitch that was underneath wasn’t quite hidden well enough, it wasn’t snug. And so finally I tried the purl 2 stitches together through the backs of the loops and hey presto, it looked great. The twist doesn’t actually notice and seems to strengthen up the edge that little bit more without compromising the stretch.
However, you may wish to experiment yourself to see if one of the other purl decreases works better for you. If you’re not wanting to swatch several times over, than I’d say the purl 2 stitches together through the backs of the loops will give you good results.

And then we repeat the sequence: knit next stitch, swap next 2 stitches over, knit next stitch then purl next 2 stitches together. You should end with a multiple of 3 stitches, and after that you can work your ribbing as desired/instructed.

I think it looks pretty good (shocking pink yarn permitting). It isn’t perfect, and it won’t be – an unbalanced number of stitches like this will need a few tricks and juggling to create a cast-on that matches the stitch pattern. I didn’t knit a whole Hat with this cast-on as I did with the 2 by 2, but I can tell you it is perfectly stretchy (that stitch we decreased is still there in the cast-on, giving us extra wiggle room) and neatens up even further after a good length of knitting.

1 by 2 rib, (knit 1, purl 2)

Now, let’s look at its sibling, the knit 1, purl 2 or 1 by 2 rib. I’ve covered this one second as it’s a little more fiddly to start, but not much, and then follows virtually the same method as the 2 by 1 with the purls and knits worked the other way around.

So, as before, we start with our 1 by 1 Alternate Cable cast-on.
Instead of knitting the first stitch as we have previously on the first row (worked flat), we’re going to slip it, purlwise, onto the right hand needle and leave it there for a bit.
Then we do the whole swap the next purl stitch over with its following knit stitch, so that we have 2 knit stitches together at the beginning. This manoeuvre is the same for all 2 by 2, 2 by 1 and 1 by 2 variants. Remember to bring the knit stitch via the front.
Once we’ve swapped the stitches over, then we slip that first knit stitch (the one that’s been hanging out on the right hand needle whilst we juggle) back to the left hand needle.
And then we decrease. And just like before, I found the knit 2 together through the back loop the neatest knit decrease for the job.
There’ll be 2 purl stitches waiting to be worked, and we purl them as normal.

And then we repeat the process again – slip knit stitch purlwise to right needle, swap purl stitch over with its following knit stitch, slip knit stitch back to left needle from right, knit 2 together through back loop, purl 2. Once we’ve completely worked all the stitches, we’ll be back to a multiple of 3 and we can continue working the next rows or rounds in pattern.

And voila.

In this shot we can see how the decrease sits much more clearly, and really, it looks pretty good, don’t you think? The twist from the knit 2 together through back loop doesn’t notice, and the decreased stitch is nice and snug and not looking like we tried to lose it. Like I said before, it’s not perfect and it can’t or won’t be, due to the pure mechanics of the stitches. That said, I do think it is worth the effort and looks way better than the alternative of a regular, non-rib cast-on.


As always, if you have a question about this technique or need some help with it, leave a comment below! I’m afraid I’m unable to offer help via email or private message, but you’re welcome to post in our forum.


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  1. Fiona Hackland

    Wow! Fantastic – how glad am I to have prompted this. Now I have to find a project to experiment with this technique. Thank you so much.

    Actually just off to cast on a cardigan with your provisional cast-on which I'm also grateful for as I find a crochet provisional cast-on a bit of a faff.

  2. meppybn

    Yes, thank you so much for clear instructions – love getting better at my knitting 🙂 Tried to comment a couple of days ago and wouldn't go through – will see if this one does.

  3. Bluewolfwalking

    Woolly, I really, really appreciate your tutorials. I haven't been knitting but a very few years, and I've learned SO MUCH from you website.

    Thank you, thank you!

  4. Kat

    I was searching for a way to do a 2×1 tubular cast-on (not possible) for a hat, but came across your instructional post as a great solution. I just wanted to clarify (sorry if I’m being obtuse) : you mention that you start with a 1×1 base and treat the first cast-on stitch as a purl/end with a knit stitch for an even amount; is that last cast-on knit stitch the same first knit stitch that you work in the first flat row (right before the purl and knit stitch switch) before joining in the round? And then after joining in the round, do you just seam the gap that is created in the first two rows knitted flat during the finishing stages? Thank you for the post and feedback in advance!

    • Woolly Wormhead

      "is that last cast-on knit stitch the same first knit stitch that you work in the first flat row (right before the purl and knit stitch switch) before joining in the round?"

      Yes it is 🙂 The start of the cast-on will always be a knot or a stitch that resembles a purl bump, so we have to treat it as a purl stitch. That then means that the last stitch cast-on will be a knit stitch, and working one row flat before joining not only helps us avoid twisting, it puts our knits and purls in a more familiar pattern for working in the round (if you joined straight after the cast on the ribbing would start with a purl stitch, which often trips people up)

      You’d then use your yarn tail to close that tiny gap at the end.

  5. Amritam

    Hi, I have a hat pattern that has a p2, k3, p4, k3, p2, k3, p4, k3, rib pattern in order to match in with the cable pattern for the body of the hat.
    Is it possible to do an alternate cable cast on starting with 1×1, or is the swapping over more than 2 stitches possible, if bit complicated! Pattern just says ‘cast on 120 stitches’, But I like the look of ac cast on for edge of a hat! Can you help Please?

    • Woolly Wormhead

      I think a ribbed cast on that matches the ribbing in your pattern can be done, but I’m not sure starting with a 1×1 alternate cable cast-on then switching it up via this route would be the best way to go – it’d take a few rounds to get the stitch count right and I don’t think it’ll be very tidy.

      There is another way to do it and as of yet I don’t have a blog post up! You can combine a cable cast-on and a backwards purl cast-on for different stitch counts, like I’ve done in my Bellefleur pattern, but in the same way you can’t just cast on a knit stitch then a purl stitch for a 1×1 rib, it’s not as simple as casting on 2 purl stitches, 3 knit stitches and so on – there still needs to be some re-adjustment.

      So the short answer is yes, it can be done but the long answer is that it’s fiddly and difficult to explain without going into quite a bit of detail, which would best be covered by a separate post. I’m going to prioritise this tutorial about combining the cast ons!

      What you could try now is casting on using these two methods combined -the cable cast-on which creates the knits, and the backwards purl cast-on which creates the purls – except that where there’s a change, cast on k1, p1 instead of p1, k1 and vice versa, then swap them around in the the first round.

      e.g. for a p2, k3, p4, k3 sequence, cast on:
      p1, k1, p1, k1, p1, k1, p2, k1, p1, k2

      and then the various stitches around in the next round to get the right pattern.

      it’ll need some tweaking as this is a suggestion I’ve not tried on the needles but that’s where I’d start.


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