Have you ever made a shawl, such as Ishbel, with a garter stitch border and yarn overs worked on every row between the border and the main body of the shawl? If so you might have found that the yarn overs next to one border were dramatically larger than the ones on the other side. This problem isn't caused by bad knitting, and there's an easy way to fix it.
If you need a refresher on the basics of yarn overs before diving into this troubleshooting post start with our Learn to knit: Yarn Overs post.
A yarn over worked before a purl stitch takes a slightly longer path around the needle, than one worked before a knit stitch, which means more yarn is used and the resulting hole is larger.
Working the yarn overs before a purl stitch as reversed (or backwards) yarn overs can reduce the amount of yarn it uses. To keep the yarn over hole open you'll need to work into the back leg of the yarn over on the following row.
If you are working on a project that has lots of yarn overs between different types of stitches you may want to swatch and alter the yarn over directions so that your yarn overs are of a uniform size.
In the swatch below we've included regular and reversed yarn overs between all combinations of knit and purl stitches so you can see the difference in size. The regular yarn overs are labelled "yo" and the reversed ones are labelled "byo".
Working a regular yarn over —bring the yarn to the front between the two needles and then to the back over the right needle. If the next stitch is a purl bring it to the front between the needles.
Working a reversed yarn over — bring the yarn to the front over the top of the right needle. If the next stitch is a knit bring it to the back between the needles.
Backwards yarn overs result in a stitch that's mounted on the needles with the leading leg at the back. On the following row you'll need to work into the back leg of the stitch to avoid twisting it.
As can be seen in the above swatch regular yarn overs worked between a knit and a purl create a substantially larger hole than they do when the purl stitch comes before the yarn over and the knit stitch comes after. Working a backwards yarn over between the knit and purl can give a more symmetrical result.
On a shawl like Ishbel all of the yarn overs at the edges on the right side are worked between two knit stitches. But on the wrong side the centre stockinette portion is purled and the garter stitch edges are knit. Consequently at the beginning of the row you work k3, yo, purland at the end you work purl, yo, k3. Prevent the yarn overs at one side from being larger by working that first yarn over before a purl backwards. Don’t forget to knit into the back leg on the next row!