What did I do wrong?
 

I made this red and white sampler with a variety of block patterns. I added the sashing to the diagonal rows, then figured the size of the setting triangles and sewed the rows together. The lower left side in the picture is the first row and the upper right with the maple leaf pattern is the last row added. Why is the last row not the right size? I'm sure it's something obvious I'm just not seeing. The corner triangles haven't been added yet.

You left off your sashing in row 6 (right side)... you just added the corner piece. That's what I looks like to me.

There is no sashing on some of the blocks.

Did the same thing on row 5, now that I am looking at it...

from here it looks good. . just quilt and bind it. Unless thre is something wrong i'm not seeing. it looks very pretty, the red and white. love it.

When I do setting triangles, you must check the sizes of all you blocks to make sure they will align properly. The only thing I see is the the setting triangles do not look like they are ALL the same size. Did you cut the triangles so that the straight of grain is on the outside edge? Bias edges should always be sewn on the bottom (letting the DSM walking feet keep the bias edge under control) when attaching them to the blocks. I always cut my setting triangles an inch larger because you can always trim them down after the quilt top is quilted. This is the quilt I finished a couple of weeks ago. Will trim it down after the LAQ has quilted it. Hope this helps.

I also think three blocks in the top of pic.

Thank you all! Maniac, all of the triangles are the same size and there was no problem with the bias edges. Tartan, I think that'll do it.