I have tied a couple of quilts and was shown a neat way of doing it without a knot. I will try to explain.
1 2
3 4
needle goes down on 1 up on 4 and back
down on 1 and up on 2 and down on 3 and up on 4. You end up with an x on the top of the quilt and a z on the underside. The thread will not come out and you do not have bumps from the knots. Be sure to leave a little tale on both ends. Happy tying.
Spice