This was requested by a YouTube friend. I personally avoid seams whenever possible. I just don't like to seam. When I bind off, I want to be done! But I do love how this makes an invisible join that you really can't see at all. Below are still photos, as well as a video of some small stockinette pieces being joined with Mattress Stitch.
My sample was done on stockinette fabric, however this could really be used with any stitch or fabric. Do keep in mind that you should add a couple of extra stitches to the sides of your fabric so that you can seam easily, and you won't lose any width. Seaming takes away from the width of your fabric - patterns that require seaming should have that fact accounted for, so no need to worry about adding extra stitches if you are following a pattern. But if you are designing your own pattern, just keep in mind when calculating the size.
OK, so here we go.
Your fabric should be placed with right sides facing. You will be working in a side to side fashion.
Use the same yarn that you knit your garment with. To make things easy, you can either reserve a length of tail from your cast on, or bind off, for this purpose. Or you can simply cut a length of yarn to use instead.
Don't seam along the immediate edge of your fabric; instead, move over to the first line of stitches. You could always move over two lines of stitches, but that will make the back side a bit bulkier.
Be sure that you stay straight as you seam up the fabric.
For the sake of clarity, we will say we are starting with the left piece of fabric here, but you may start with whichever piece of fabric you like.
Beginning at the cast on edge of the left piece of fabric, insert your yarn or tapestry needle into the cast-on edge stitch, then do the same on the right piece of fabric.
On the left piece of fabric, insert your needle under the first strand of yarn between the edge stitches and the first line of stitches.
Repeat on the right piece of fabric.
Continue moving left, right, left, right and so on, until you reach the top of your fabric. Then, insert the needle into the stitch along the bind off edge on both the left and right piece of fabric.
Now, gently pull on the tail of your yarn to tighten things up. Pulling from both ends is easiest for me. You will see that the yarn you used to sew up disappears like magic. Don't pull too tightly or your fabric will become misshapen. Just pull gently until the seam is neat and even. Weave in the loose ends.
Now, if you are like me, you may be scratching your head and saying "Huh?!" after reading that. I find visual aids much more easy to understand than the written word. So, here are some pictures, and the video.
These are the strands that you will be picking up and running your needle and yarn under
Yarn has been inserted into the cast on edge stitches of each piece of fabric
Needle going under the first strand
I have started weaving from left to right, left to right
I have now finished weaving all the way to the top of my fabric, and the yarn has been placed into each stitch along the bind off edge as well
The yarn used to seam has been pulled tight, and I now have an invisible join!
You can see how beautifully these pieces of stockinette fabric have been joined. Here is a sample of seed stitch fabric I joined, which is just as nice.
How great is this join?! Simple and easy to do - you can use any yarn, too. Other than the Spit Splice, or Felted Join, this has to be my favorite method of joining a new ball of yarn. Rather than still photos, I am just doing the video on this one. If you haven't tried this yet, you must. You will need a yarn or tapestry needle to do this, and about 30-60 seconds. That's it.
In the picture above, I used two different colors just for ease of demonstration, but most likely you will be using the same color of yarn. Even if you are using two different colors, once you've knit the join area, it really blends in well with the fabric and you will be hard pressed to tell where the join is once it is done.
