This is my second year of gardening. I want more success so I've decided to build a raised bed. I am in north FL. I was thinking of filling it with half Black Kow composted manure and half bagged organic garden soil. Will this do the trick? Am I missing something? Is there anything special I need for in FL? Is 11 inches a deep enough bed?Is their a cheaper way to do this - I am a little too late to begin composting for the spring. Thanks for helping a newbie.