Sometimes the starting row on this scarf is looser than the rest of the rows. To tighten it up, I have done one of two things (or both, if needed):

1) Crochet the first row with a size smaller hook than what is used on the rest of the scarf.

2) When finished with the scarf, if the beginning edge is still looser than the rest of the scarf, I go back and crochet along the open side of the beginning edge - using the same linen stitch pattern.

When doing this second step, the stitches on the other side of the foundation row will be pointed in the opposite direction as those in the rest of the scarf, but it blends in just fine. I have to really study the scarves I made thus far to even detect the different directions of the stitches. And even then, it’s a non-issue. Crocheting two rows (of alternating colors) on the opposite side of that beginning row will make it virtually impossible for you to see it.