Stem stitch is not a stitch I use a great deal for outlining my figures because it tends to create a thicker line than I like but it can make a good outline for clothing or a decorative line but also fabulous hair.
For the longest time I have been stitching two different stitches under the mistaken impression that they were the same stitch just approached from a different direction. I thought both stitches were stem stitch but it turns out that one was stem stitch while the other was outline stitch. I had even seen it referred to as outline stitch but there are quite often different names for the same stitch so I didn't pay too much attention. It was only when I came to do some research for this post that I realized that they are indeed two stitches. One, outline stitch, has a smoother edge while the other, stem stitch has a more jaggedy edge
The example above is outline stitch (it is stitched onto a piece of Robert Kauffman Essex linen in dusty blue).
and I stitched the top straight row using 4 strands of thread. The second straight row and the curved row were stitched using 2 strands.
To begin make a straight stitch but before you pull the thread all the way through bring your needle up through the fabric about half way along the stitch making sure the loop from the first stitch is above your needle (or further away from you). This is what makes it an outline stitch.
Pull the whole thing through and you can see that my thread, in the picture above, is coming from underneath the first stitch. Now take your needle down about half a stitch length from the end of the first stitch (your actual stitch length goes back to the middle of the previous stitch). Again don't pull your stitch right through
Now bring your needle up at the end of the previous stitch as shown above. You will continue in this way until you get to the end of the line.
You can also follow a curved line beautifully. Making the stitches shorter or longer can also change the way the stitch looks. I like to use this stitch with more threads to create a thick rope like line, it makes fabulous hair because it curves nicely.
For stem stitch you create your first stitch but pull it through fully then bring your needle just above the middle of the stitch as shown above
Next bring your needle down about half a stitch length from the end of the first stitch as you did for outline stitch and pull through
Bring your needle back up just above the middle of the last stitch and continue in the same way
I'm sorry for the slight blur (fast fading light in winter!) Hopefully you can see the stem stitched pink line has a more twisted edge than the lower green outlined line. Both can be used well on curves you just need to decide whether you want a smoother edge or a more decorative edge for your stitching.
A fun use for stem stitch are these little flowers. I made a french knot using 4 strands of a paler pink (I double wrapped it).
Next I made a small straight stitch along the edge of the knot (you can push it into place with your fingers so it doesn't cover the knot).
Then, using the same stem stitch technique, I brought the needle up just above the centre of the first stitch and made another stitch moving around the french knot centre. You just continue going round until the flower is as big as you would like it to be. The stitches should be a little longer on each round.
Have a lovely weekend and I hope you find some time for a little cosy stitching.