Hello everyone!!! PLease help me before I go nuts.
I have a 8 in. piece of backing, the batting and now I am using 2 in. strips to diagonally cover this, so I can make a scrappy quilt. My question is this: When I am sewing the strips onto the backing, it all goes well until I turn it over and my backing piece is puckering where ever I have sewed and it's ugly. I dont want an ugly quilt when I turn it over. What did I do wrong? I have attached pics of front and back of my square. The other square I have made looks worse than the one you see here.
Thank you and any help would be much appreciated.

Are you using a walking foot? If not, that may help a lot.

First silly question - are you using a walking foot?
Are you pinning the layers together so the backing stays flat?
Is your stitch length too short?
Any of these will cause puckering.
Why not machine your strips to muslin or similar, join your blocks, and then make a sandwich with batting and backing so you quilt it all at once.

I am most definitely using a walking foot. Thank you for your response. Is it because I sewing diagonally maybe? I just don't know.....

diagonally could cause puckering because you are sewing along the bias.

Yes I am pinning. Yes I am using a walking foot and my stitch setting is set as long as it can be. THe reason I am doing it this way is because I wanted to try the scrappy quilt way combined with quilt as you do method. Am I making sense? I am so new at this, my sewing lingo may sound a little nutty!! Thank you for responding.

When I read the idea off the net, it never told me to get ready for puckering. Had I known this, I would have never started. LOL and I wanted to really do this. Thank you for responding. I need all the help I can get.

I don't know if this will help but maybe you can try adjusting the thread tension so it's a little loose.

sometimes stitching one line one direction and the next from the opposite direction helps. also not having too short a stitch length.
you could also use spray basting if necessary. then the fabric would not move on you. and it can be repositioned if need be before stitching.

I agree with alternating direction of sewing the strips.