If you have done a good job of weaving the ends in it should not come undone. The following tip will not work with ALL yarns (chenille, for one), but is my favorite way to weave the ends in when possible. Say you have 4 ply yarn. separate the ply in the piece you are going to weave in (hold one ply between the index finger and thumb of your right hand and the rest of the ply(s) between the index finger and thumb of your left hand. Lift until the piece you are working on is dangling in the air and let it untwist until the one ply is totally separate from the others. Weave this ply in. Repeat with the other plys and when you weave them in, go through a slightly different spot than before. This way you won't see a thick area as you sometimes do when weaving in the entire piece. Also, when you weave in, make sure to go more than one direction (go through an area, then back a little ways, then back in your original direction again). I'm sure there are other (maybe even better) ways to do this, but this has worked extremely well for me. It's especially nice for wearables, like socks, where the extra bulk might be uncomfortable.

Thanks Donna. Maybe I haven't been leaving a long enough piece to weave in...

ginger

Ginger,

Do not knot your joinings unless it is chenille or the yarn manufacturer instructs you to do so. Weave your ends into the work. When I am crocheting, I like to make my last YO loop with the new color.

To knot, or not to knot? That is the question. Ginger is right. Unless it is absolutely necessary do not knot.