mattress stitch with uneven rows

[agelfon]

I am seaming the sleeves and sides of a sweater that I knit in stockinette stitch. I discovered that the back and front of the sweater have different numbers of rows and I know I should be seaming so that the underarm comes together at the armhole. How should I adjust for the discrepancy in rows at the side seams so the seaming looks right? Any advice would be greatly appreciated!

[Ingrid]

First, I'd suggest clipping the sides together. You can use strands of yarn to tie the sides together, or what I like to use are little hair clips. Anything to hold it as you seam, making sure the bottom and top edges are even.

Then, as you seam, you can skip a row here and there on the longer side as you work your way up, tugging on the sweater to keep it from getting tight. It should work out fine.