Poly/cotton blend?
 

I'm putting together a baby quilt - the top is embroidered blocks (Jack Dempsey Peek-a-Boo nursery quilt blocks). The material the embroidery is stamped on is cotton/poly broadcloth. Once the squares are embroidered a sashing is added to make the quilt top. Should this material also be a cotton/poly broadcloth? What about the backing material? I usually only use cotton for quilting so I'm not sure about this. Thanks!

I have mixed fabric types before - just pre-wash everything so any shrinkage happens before the quilt goes together. That way if something shrinks a lot more than others you'll still be OK. Your pre-stamped squares are probably OK without pre-washing since poly doesn't shrink; so I would assume poly/cotton would shrink less than pure cotton. And watch iron temp, poly can't handle as much heat as cotton.

i agree with sewnoma... i have mixed fabrics in the past and never had a problem because i always preshrink

I have mixed cottons and cotton/poly blends in scrap quilts with no immediate problem. On one quilt for my dog one piece of poly/cotton blend did not hold up as well as the rest of the quilt. I solved that problem by adding an applique flower covering that block. That has happened only once but I have found some old utilitarian quilts that failed in the same way. Generally there should be no problems. I look forward to seeing your finished quilt.

My daughter uses poly/cotton all the time with regular cotton. She also prewashes everything. I quilt her tops and I have noticed that if a block is not really flat after sewing you can't steam it or starch it and shrink the excess to flatten the block. It makes it a challenge to quilt her tops. I have been talking to her about precision piecing and she is getting much better.

I have only collected 100% cotton because when I started sewing, that is what we were taught. I only come across with poly in the low cost discount fabric stores. It might work out better with a baby quilt with all the washings.

Agree with the above and also point out that sometimes the polycotton is harder to work with in intricate blocks with small pieces. Some will not want to press and stay in place since it is designed to resist creasing.

I've mixed fabric types. I'd probably go with the cotton backing. My experience with mixed poly cotton and cotton is that the polycotton tends to wear out first.