In this post are links to ten different methods (all illustrated) for working in ends, 8 of which are as-you-go.
1. The Russian join--this join is well-known as a simple method of joining two colors, but it works for same-color joins just as well. An example of where you might want to work in two different colored ends is with stripes or with fair-isle methods. An example of same-color joining is here you run out of yarn and need to switch in a new ball of the same color. This join, like most the others on this page, not only secure the transition stitches, but also works the ends in as-you-go.
2. The back join is an improved Russian join--with the back join, it is possible to exactly choose the spot where the yarns will change, which is not the case with the Russian join. Another improvement is that the back join is WAY faster than the Russian join--no need to dig out a sewing needle! Like the Russian join, the back join is usually touted for changing smoothly from one color to another, but it is also a nifty trick for same-color joins. Also like the Russian join, if you use the back join, there will be no ends to work in at the end--all you have to do is snip off the excess after blocking and you are done!
3. For same-color joins, there is also the overlap method. (scroll at link) This method is probably the very fastest of all. The overlap method will not work (or at least, will not work very well) for changing color, but for same-color joins, there is nothing simpler. With this method, and depending on the yarn used, it may be necessary to leave little tags (tails) on the inside where the yarn changed, but because the stitches are overlapped, these tags will never work free--the transition stitches will remain tight and good looking for the life of the garment. This method can be adapted for lace, also, without the tags.
4. Not to be confused with the overLAP method (above) we also have the overCAST method. For delicate work, or for thin yarn, this trick lets you work in the ends with no added bulk on the face of the fabric. Therefore, this method is to be preferred to the Russian- or the back-join when bulk is an issue: both of Russian- and the back-join add a bit of bulk to the fabric surface, which this overcast method does not. Like the Russian- and the back-join, with the overcast method, the ends are worked in as-you-go. You need only trim off the excess after blocking, and your fabric-finishing is complete.
5. Another great (if slightly icky) method for dealing with ends is the spit-splice, also called "felting ends" (scroll at link). This works best for same-color joins--for different color joins, you would have a length of yarn which had both colors at the same time. Felting ends is not so much a method for working-in ends--instead, felting actually eliminates the ends!
6. We also have two methods of working in ends using a sewing needle--an after-the-fact fix for loose ends. The first of these is the art of weaving in ends. With weaving, the end is worked into the fabric face along the same path as the underlying stitches--it is a species of duplicate stitch. A sub-set of weaving is how to weave ends in ribbing. Weaving is quite, quite secure, but it can add a little bulk on the fabric face, so if this is a concern, consider using the method below, instead.
7. The second method of working in ends with a sewing needle is the skimming-in method. This method is not quite as secure as the weaving-in method, but it avoids bulk on the fabric face, and so is better than the weaving-in method for thin yarns or delicate work. Both the weaving-in and the skimming-in method work with different color yarns OR same color.
8. A sub-set of the skimming-in method occurs when you are facing a very short tail--so short that you can't really thread the needle. For this problem, we knitters can adapt a classic dressmaker's tip for working in the too-short ends.
9. Another place where ends might be an issue is at the beginning of a circular knit. That tail hanging where the join occurs can work itself loose and get ugly. A trick for preventing this AND working the tail in at the join is the three-in-one TECHjoin. Further, the three-in-one TECHjoin also prevents the nasty "jog" where the first round meets the cast on.
10. We end with a quite-specialized trick for working in your ends on textured stripes. This trick shows how to make jogless stripes in textured fabric AND work in your ends-as-you-go. It's a nice time saver for those who like to make stripy ribbed hats.
Good knitting! --TK