This is a step-by-step tutorial on how to pick up and knit a facing or a hem. A facing is a shaped piece of fabric that is used to cover up raw edges. It is used most often in sewing on the insides of button bands, collars, and neck trim. In this case, I am going to knit a hem that is also a facing. But the process applies to both.
In knitting, facings are most often used to enclose steeks but that is not their only purpose. I am using it here to enclose a steek.
Step 1 is to pick up the sts along the edge that is going to be enclosed. The key here is to pick up sts along a straight column of sts so that it looks neat and finished. This is a view of the picked up sts from from the wrong. You can see that the picked up sts follow a straight line. It is very easy to move a half st over. If you notice this, it takes very effort to start over.
It is easier to see along the yoke where there is less curling. When I picked up these sts, I noticed I was a half-st off when I got to the yoke because I started at the hem. That would have removed a half st from the yoke, which would have been noticeable. So I started over.When you pick up sts, the steek (in this case) automatically turns under. The steeked edge tends curl inwards due to the stockinette. If another st was used, it may not turn under until you pick up the sts. See how nice and flat the steek is? This is why I didn't want to use the crochet steek. If I was knitting, for example, a button band and wanted to knit a facing at the same time, I would pick up a st and create a st by doing a yarnover. So the pattern would be *pick up and knit 1, yo, rep from * to end. Then I would separate the yarnovers by putting them on a different needle. The picked up sts would become the button band and the sts created by yarnovers would be used to knit the facing in the other direction as we will be doing here.
Step 2 is to knit the facing. This is usually in stockinette. Sometimes a thinner yarn is used to knit the facing using the same size needle as the body. This makes for a thinner fabric which cuts down on bulk. Facings can also be used to provide a pop of color when the finished edge turns inside out. This is used a lot on sleeve cuffs. When you fold the cuff up, the facing gives you a different color on the end of the sleeve.
Here is a view of the knitting from the wrong side. In this case, I am knitting a picot hem. So I created the picots along the turning edge by a row of k2tog, yo. After that I continued knitting the hem/facing. In this view, I am part-way along the hem. You can see the row of yarnovers that will make the picots.You can see how flat the steeked edge is and how nicely it folds to the inside. I am doing this all along the front edge.Once you have knit the facing with enough depth to cover the steek, most of the work is done. Step 4 is to verify that your facing will cover the steeked edge. You can fold it along the turning edge (the row of yarnovers here) to verify that it is deep enough. I didn't take a picture of that as I ran out of hands.
Step 5 is to bind off the facing/hem.
Step 6 is to sew it down. I like to sew about every 2-3 sts, skimming through the wrong side of the fabric and then up through one of the bound off sts. If you go all the way through the fabric, it may be visible on the right side. But if you go through the purl bump part-way, it will be invisible. Make sure that you aren't pulling the sts too tight as you sew. Turn it to the right side frequently and check to make sure that the sewing is both invisible and doesn't interfere with the elasticity of the knitted fabric.
You can just run the end of the yarn into the hem/facing and you are done! I like to do a double st as the beginning and and end rather than using knots.
I hope this helps you visualize the process.