A Stretchy CO and BO by Heather Storta

A Stretchy CO and BO by Heather Storta

Learn Something New! Summer 2022

Sometimes extremely stretchy edges are desired for our knitted projects. The cuff edges of socks or the hem or brim of a hat, for example. When stretchiness is of utmost importance, consider using the cast on and bind off presented here. While these edges do not exactly match one another and wouldn’t necessarily be considered a “matching” cast on and bind off, they certainly match each other well in stretchiness!

Slip Knot Cast On

Slip Knot Cast On
Slip Knot Cast On seen from the edge

This cast on is also known as the buttonhole cast on, or Jeny’s Stretchy Slip Knot cast on. It is simply a series of slip knots placed on the right-hand needle. You could also make them from left to right onto the left-hand needle, if desired. The front and back of the cast on look nearly the same.

This cast on works well only with smooth yarns and would be extremely difficult to work using a boucle or tweed or other textured yarn. A singles yarn may not be of sufficient strength, either. If you are using a yarn of that type, consider using a similar color and weight of yarn in a more desirable texture and strength to cast on and then switch to your working yarn in the first row of knitting. This is because the length of yarn is pulled through the slip knot to snug it up against the needle, and the yarn will need to be able to withstand some repeated friction.

This cast on looks best against 1×1 ribbing. It is not so attractive against stockinette, so a different cast on would likely be a better choice for that fabric. It is also a nice choice to use for casting on in the middle of a row—for buttonholes, for example.

To work this cast on, begin with a slip knot, leaving a tail to weave in later. Place the slip knot on the right-hand needle.

Make a loop around your left thumb—the working yarn should travel between your thumb and forefinger, forward around the thumb and then under the strand attached to the needle and to the back. Then place the working yarn over the index finger and secure the yarn with your other fingers.

Insert the right-hand needle tip under the front of the thumb loop, from below, grab the index finger strand from above with the needle tip, and scoop it down into the thumb loop.

Move the loop on the right-hand needle immediately next to the prior stitch, drop the thumb loop, secure the new stitch with your right-hand thumb and index finger, and pull the working yarn down to make the slip knot.

Slip knot complete

The knot may be difficult to get snug and tight. Tug on the rear part of the knot to release the tension if it is refusing to tighten up before pulling to tighten some more.

The goal is to have tight slip knots as close to one another as possible. This may seem counter-intuitive and opposite of many other cast ons, but it is necessary with this cast on. Otherwise, the cast-on edge will look very loose and sloppy once more rows of knitting have been worked.

Repeat these steps for the desired number of cast-on stitches.

This video tutorial shows how to work this cast on.

Jeny’s Surprisingly Stretchy Bind Off

Jeny’s SSBO
Bind off seen from the edge

This bind off is—as it says—surprisingly stretchy. This is a variation of the yarn-over bind off method and was the brainchild of Jeny Staiman. It is not a sewn bind off, so a tail does not need to be cut first and you can simply work with the working yarn. It looks similar on both sides of the fabric.

This bind off actually works with any type of stitch pattern. It looks great against ribbings, though, and does a great job of allowing them to stretch while bouncing back into a ribbing pattern when released. Because a yarn over is worked between each stitch, there is plenty of room for the bound-off stitches to stretch to their full potential.

To work this bind off, first make a yarn over on the right-hand needle before working the first stitch. Assuming we are binding off 1×1 ribbing and a knit stitch appears first, you create a “backwards” yarn over by bringing the yarn around the right-hand needle clockwise (or behind the needle first, then over and towards you, and then down and back to the back). If a purl stitch appears first, you would instead make a normal yarn over.

Then you knit the next stitch.

Yarnover and first stitch knit

Then pass the yarn over over the last stitch on your right-hand needle.

Now a series of steps will be repeated across the stitches to be bound off.

First, make a “normal” yarn over by bringing the yarn over the needle from the front to the back and then forward between the needles ready to purl.

Yarnover made

Then purl the next stitch.

First stitch, yarn over, purl stitch now on RH needle

Now pass both the yarn over and the first stitch over the last stitch on the right-hand needle. I tend to do this in two steps: pass the yarn over first and then the stitch. This way the stitches being passed over stay lined up on top of one another nicely. But you can pass them over together if you wish.

Next, make a backwards yarn over, knit the next stitch, then pass the yarn over and the first stitch over the last stitch on the right-hand needle.

Continue across the row of stitches in this manner (yarn over, work next stitch, pass yarn over and stitch over last stitch) until the last stitch remains. Cut tail and pull loop through remaining stitch on right-hand needle.

If you are binding off a stitch pattern other than 1×1 ribbing, you will follow the same steps of making a yarn over before working each stitch, then binding off the yarn over and the preceding stitch. You will make a backwards yarn over before any knit stitches, and a normal yarn over before any purl stitches.

This video tutorial shows how to work this bind off.


Cast on stretched
Bind off stretched

These edges are great choices when you need a super stretchy edge—whether it is the cast-on edge or the bind-off edge. Give them a try sometime!


Bestor, Leslie Ann. Cast On, Bind Off. Storey Publishing, 2012.

Sease, Cap. Cast On, Bind Off. Martingale, 2012.

Stanley, Montse. Reader’s Digest Knitter’s Handbook. The Reader’s Digest Association, 2007.

Pattern Associated with Article — Gibson Headband

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Copyright 2022, The Knitting Guild Association, Cast On Summer 2022, All Rights Reserved

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