What color thread for quilting
 

I have a top that is 50% Kona white with the other 50% being medium to light pastel florals. The border will be one of the medium florals. What color thread do I use for the quilting? Don't know if I should use white, off white, or a pastel.

Off white would show up the most. I've done both of the others. I personally like the look of crisp white slightly more than pastel on white/pastel, but that's just my personal taste. Either one would blend equally well and look good. When I'm trying to decide -- if I have both threads -- I will "puddle" some thread on the quilt. Just unwind maybe 18-24" onto your quilt top and decide which one you like best. You really can't go wrong with any of the 3 choices.

Do you want the piecing to be the star? Or the quilting? Can you or do you want to bother with changing thread? Or do you want to do an all over?
I have liked the results of white on white and then color on color, but I am also a fan of variegated when I do an all over design.

Cream color will be perfect. I use cream color all the time on white - it doesn't look dirty.

I like snow white, if your Kona is snow white. I use a pearl white if your kona is a soft white.

Usually I dribble the thread on the quilt to see what looks best. I agree with Tartan, white Kona should have white thread.

The white will be good.

I'd probably go with white but I always pull out 20" of thread and puddle it on the quilt and audition a thread. Sometimes I'm really surprised which thread I end up using!

Have you thought of a pearl grey which would show up on both white and pastel.