I've knitted quite a few pairs of leg down socks over the last several years from several different patterns. What I have noticed on most all the instructions is that they don't specify what cast on method to use. I would think this would be important and especially for socks. It seems that most of these instructions just assume that the knitter is an expert and should already know which cast on method will acheive the same look and function for that sock pattern as the the author achieved.

It can be pretty confusing if you are new to sock knitting and double pointed needles. There are so many different names for the same cast on methods and some of them have the same name as another but are very different depending on what reference you choose to follow.

Thumb Method Cast On (aka: Tail Method, Long Tail Method, Double Cast On, Continental, Sling Shot, Two-strand, or Y Cast On), which is known by most knitters as a general purpose cast on with some stretch. Personally, I have had the best look and elasticity for my socks by using this method.  I also like it because it stays on the double pointed needles better and it doesn't twist as easily when dividing your stitches onto the other needles.

The Wrap Cast On (aka: Loop Cast On, E-Wrap, single Cast On) is said to be the stretchiest and the easiest of all the cast on methods.  Although I agree that this is the easiest of all the cast ons, I personally don't feel that it leaves a nice cast on edge and I feel that it can be overstretchy.   It might be a good choice for diabetic socks? 

German Cast On (aka: German Twisted Cast On & Twisted German Cast On) is very good for socks. Through recent research on sock cast on methods, I have found that many knitters are just raving about this method even though it looks a little tricky.  I haven't tried this one yet but plan to do so on my next pair of socks just to test it out.

So, when choosing a sock cast on method the choice is really up to you, there are really only two things that you should keep in mind:

1) If your pattern instructions don't specify what cast on to use, then choose a cast on method that you are comfortable with using. There are many options available that will acheive a similiar outcome in most instances.

2) You want some stretch, so choose a cast on method that will give you an appropriate or desired amount of stretch. You don't want a cast on edge that cuts off your circulation around your ankles, this can be painful for anyone but is especially bad for diabetics.

Happy Knitting!