Grafting seed stitch

Egads! I've been helping Hanna with a beautiful sweater that has been causing a bit of trouble. The back came unraveled along the side where two balls of yarn had been joined, and unfortunately, the bit where the two rows needed to be grafted together was in seed stitch (!!).

So after much searching and wringing of hands and pulling out of hair, I found this amazing tip at KnittingHelp:

I think if both your ends have identical stitches on the edges* you're joining, then you could follow the instructions for kitchen in ribbing.

*Identical in that you have a purl stitch across from a purl and a knit across from a knit. That way when you join, the joining row would provide the other stitch.

Single Rib Grafting
In this case there will be four steps, two for the Knit stitches on each needle and two for the Purl stitches. I am going to assume that the first stitch of the Single Rib sequence is a Knit (for seed stitch, we'll simply assume this first stitch is a Purl, to offset this row by one stitch). Remember, this will line up properly only when grafting the top of one section of the fabric to the bottom of another.

Preliminary step: Near/Purl, far/Knit (that is, into the Near needle--the one closer to you, go purlwise, then into the far needle go knitwise, just as you normally do to start)
1. Near: Knit/drop, Knit
2. Far: Purl/drop, Purl
3. Near: Purl/drop, Purl
4. Far: Knit/drop, Knit

But the place where Hanna's sweater needed to be grafted was the opposite, so, a switch had to be made in the setup row:

Preliminary step: Near/Knit, far/Purl (that is, into the Near needle--the one closer to you, go knitwise, then into the far needle go purlwise, just as you normally do to start)

And then I simply started with the above row 3 instead of with row 1 (rearranged below):

3. Near: Purl/drop, Purl
4. Far: Knit/drop, Knit
1. Near: Knit/drop, Knit
2. Far: Purl/drop, Purl

The result? a virtually invisible fix, and MUCH better than having a giant hole in the side, or having to re-knit the entire back (!!).