Ack! Tension
 

So I FMQed my daughter's quilt in a four-leaf clover pattern. It looked fine from the top, besides the usual wonkiness that comes from being a beginner at this stuff. So I happily kept on quilting, without bothering to check the reverse side (classic newbie mistake I'm sure). When I was all done I was thrilled at how it looked until I turned it over. Almost every one of my clovers looks terrible from underneath. On some of them you can just see the little loops from the top thread and on the others the bobbin thread looks just like a straight piece of thread pasted on the fabric (if that makes sense). It doesn't even look like the top thread has had any affect on the bobbin thread. It looks pretty bad. Great from the top though.

Weirdly, some parts of the backs look fine; then tension issues seemed to only be a problem when going in certain directions while FMQing.

I'm sure I already know the answer. :( But should I tear it all out and start again?

It's not tension. Your movement of the quilt is too fast for the needle speed. It should pull out fairly fast from the back.

It could be tension, but as Scissor Queen said, most likely that you're moving too fast for the thread to keep up. I'm just learning too, and am happy that my new Janome has speed control on it. I'm finding that the faster speed is better for me, but I work on a practice sandwich before starting on the real quilt to make sure the tension and my movements are working properly. Keep practicing. It takes a while but it really does get easier and better looking over time.

Try increasing your top tension a notch or two. That should help.

Dang, I was hoping someone would say "Oh it's OK, leave it in." :-) Thanks for the replies and suggestions!