If you've been reading other posts, you've probably picked up on the fact that I am the world's laziest knitter. Being lazy and curious has it's advantages, in that I am constantly looking for new ways to save time, energy, and brain power.
I've been fascinated by the methods of provisional cast-ons that I've read about, as well as the intense discussions of the stretchiest cast-on. Most of the former revolve around crochet hooks, extra threads, unpicking same, carefully scroonching stitches onto needles, and so on. And the latter, well, suffice it to say that I know perfectly well how to do all the exotic methods, but why bother? Of course I have another option for you that encompasses both provisional and stretchy. And it couldn't be easier.
Take your knitting needle (any kind) and a circular needle with a nice cable. Make a slip knot and put them together thusly.
Wrap the yarn around both the needle and the cable for the number of stitches you need, plus some extra wraps.
I can't give you an exact number here, but for 20 stitches, I wrap an extra 5 times, for 100 I wrap an extra 20. The wraps get sort of messy at the end, so I just make some extra. As this cast-on takes less than a minute for 100 wraps, it really doesn't matter, because you will drop the excess at the end.
Turn the needle over so the thread is coming from right to left. Start knitting.
Keep knitting until you have the correct number of stitches.
Unwind the excess. Drop the slip knot if you want. Whatever.
Now, at this point, your provisional stitches are on the cable of the circular needle. I happen to like to use KnitPicks cables and screw on their needle cap thingies. But you can leave your stitches on the circular needle--make sure you do put some sort of cap on the end so the stitches don't fall off.
Turn the work around as usual and continue knitting away. Here is the second row half-done.
That's it. When you are ready to do whatever with your provisional stitches, you can: Turn the work upside down and knit the other end if you are starting from the center, attach your lace edging, or do some grafting.
Now I hear shrieks of WHAT ABOUT THIS STRETCHY CAST-ON YOU PROMISED??
Oh. Well. Turn the work upside down and do Elizabeth Zimmerman's Sewn Cast-Off on the stitches currently resting on the cable. Great for socks. Great for lace. If you use the sewn cast-off method to end your piece, well, both sides now match, don't they?
Elizabeth Zimmermann's Sewn Cast off from Knitting Without Tears.
Break yarn, leaving a tail about 4 times as long as the circumference of the edge. Thread a tapestry needle.
* sew forward (right to left) through two stitches as if to purl, leave the stitches on. Sew backward (left to right) through one stitch as if to knit and remove the stitch.
Repeat from * until you run out of stitches. Work in tail on the inside of the knitting and trim any excess.