Diane, you mention stockinette, but then you say you made a ribbed scarf (4-2), I'm guessing you mean something like knit 4, purl 2? I would think that wouldn't curl too badly. But I do know that if you have made something with acrylic in stockinette and block it, as you wear it, I guarantee that it will slowly begin to curl up again. You could pick up stitches along the edge and do a couple of rows of garter or seed stitch to fix the problem.

Yes Donna, you have it right. I now know that if I ever want to do ribbing OR stockinette I better do it in something other than acrylic or acrylic blends. It totally ruins the effect to have it all curled up on itself!
I was planning on going along the edge of this scarf with a row or two of single crochet as an accent, as I'm doing a border at each end of crochet too. Do you think that would help at all to uncurl the dumb thing?
Diane

Diane, the sc should help, but I don't know if just one row will be enough. All you can do is try.

Apologies, but the curling is due more to the STST than the acrylic. Stockinette will curl in any yarn . . .

Well, yes, I think we've established that as a fact. The question was whether blocking would flatten it out. And it seems that the answer is if using acrylic or acrylic blend yarn, then no, the yarn will not flatten out for any length of time and re-curl. Does everyone agree on this? Am I correct then in assuming that a 100% wool yarn can be blocked and uncurled when knitting in these patterns?
Donna, I did get two rows of sc on each side and have an interesting ruffle effect going on. I think I like it!

Stockinette stitch will curl with wool and other yarns too, as useratl mentioned. And no, blocking will not uncurl it permanently, in wool or any other yarn.

Yes, I concur with the others. Stockinette is going to curl, no matter which yarn you use. If you like the bit of ruffle you are getting, that's great. If you prefer not to have the ruffle, you might try experimenting with spacing your edge stitches a bit further apart, or combining two stitches into one occasionally.