We have used it in the mix before, Becky. I think the important thing beyond paying attention to the different levels within each brand of fertilizer is to keep 'mixing it up.' Use one fertilizer one time, and then a new one the next time. Rotating between two or three. I really like the results I get by using MSU fertilizer and Fish Emulsion, but I still use Miracle Grow and others in the rotation. (And, as you know, some plants need a bit different levels of the different parts, so a nice mix within the whole collection seems to keep everyplant happy.) JMHO and practice.

Cheers,
BD