You probably want more different sources of compost such as mushroom compost, worm castings, chicken manure, etc., as Mel recommends in the book.

I've used it before because that was all that I had... and it was successful for tomatoes, corn.. the peppers didnt do so well, with it, and I think its because it wasnt mixed with a variety of other stuff

It's a good start. I would definitely add in some vermiculite or perlite with the peat though.

If you have an Agway near you, you can get a 3cu ft bag of vermiculite for 23 bucks. Dont ever buy vermiculite from one of the box stores, absolute rip off...