If I work stitch for stitch my edging would end up ruffled because my gauge is much looser than the original knitter/crocheters. So I thought I would take the opportunity to make this little post.
This is how you can tell if you will end up with a ruffle or a pucker wend adding a crochet border to a project weather it is knit or crochet.
Sorry for the quality of these photos, I took them with my phone. But I think you can still see what I'm talking about. Here I have corchet along the edge of a square. but you can see the edge of my stitch is nearly at the edge of the next stitch I have not crochet into. If I keep going at a stith for stitch rate, I will end up with a edging that ruffels. so when I see my stithc start to run ahead of the stitch I hven't worked into yet I know it's time to work 2 as 1 off my square edge.
So to make up the difference here I have simply inserted my hook inot hte back loop of the next stitch and the one after that and worked them as 1. You can see now my stitch is no longer leaning over the next stitch and I have compensated for the difference in gauge. You want your edging stitch to be directly above the stitch you are working into. I really like to crochet into the back loop (if able) when this may be an issue because you cannot see the crochet 2 tog and it doesn't interfere with the edging lines.
Some squares I had to sc 3 and than sc 2tog to get the edging to be nice and smooth.
An if you are working your edging and it seems your stitches are starting to pull back you need to crochet 2 into the 1 on the next stitch to make up for the difference. IF you don't than you will end up with a tight edge that may pucker and curled up.
And that is how you read your crochet and you will be able to keep your edging in match with your project if they happen to be at different gauges.
Now I did have one knitted square that was so tight on the edge I could not get my I hook into the stitches to make an edging. the way I adjusted for that was I did 1 round with a G hook because it fit more easily into the stitches and than the next round with an I hook and didn't increase stitches in the corner as the hook size increased it naturally.