Tubular cast on creates neaten and yet elastic beginning edge. This method can be used for working either your knitwear flat or in round. If you're working in the round you should work the cast on and 2 tubular rows on straights before switching to your circulars and joining the round.
TIP: I like to use much thinner yarn for provisional CO then working ayrn and smaller size of spare needle then working needles, it makes things much easier to pick up the stitches.
Please note that for tubular CO you need to provisional CO half of your total number of stitches onto your working needles.
What you'll need to make provisional CO and then tubular CO:
a set of working needles or circulars, spare needle, crochet hook, working yarn and spare yarn, to make things clearer I used bamboo needles as my working needles and an acryle one as my spare needle
with spare yarn and crochet hook make a knot and chain 1
join working needle, bring the yarn from the back around needle to the front, and chain 1
bring the yarn back to the back of a needle
bring the yarn to the back
again draw up a loop bringing the yarn from back to front of needle and chain 1
repeat to wave yarn around the needle and chain 1 untill you reach the number of stitches you wanted to cast on
make a few more chains without waving yarn around the needle and secure last chain with locking marker (optional, if you are worry about ripping, as I am :)) now you have the provisional cast on row which can be used to many other knitting projects, but in this tutorial in next step I'll focus on tubular cast on
join the working yarn to start knitting as usual
beginning with a knit row, work 4 rows in stockinette stitch
unzip provisional cast on, and slip the stitches on spare needle, note that first stitch won’t really seem
like a real stitch but a loop of yarn, make sure you slip it onto the
you will now have half your total number of stitches on your working needle and half on the spare needle, slide the stitches along the spare needle so that both needle points are positioned next to the working yarn, I’m aiming for a 2×2 rib arranged: p1, (k2, p2), k2, p1, for other arrangements you will need to adapt the following directions
fold the spare needle up behind the working needle so that your knitting is folded in half and the spare needle is behind the working needle, purl 1 from spare needle
knit 2 from working needle
purl 2 from spare needle
repeat last two steps until 3 stitches remaining, then knit 2 from working needle, purl 1 from spare needle.
For flat knitting work in rows in the rib pattern as established. If you are knitting in the round join the round at this point and continue in the rib pattern as established. When you have finished knitting, sew together the first couple of stitches.
Also you can always try with different ribs, for example you can use this techinque for 1x1 rib or make two stockinette rows for more elastic beginnig.