More Words, Deeper Hole

Consider: A body buried in the ground for more than a few months, unprotected, is basically going to be disintigrated by worms and other subsurface carrion. In a high-humidity area like New Orleans it might be measured in weeks. Now since most zombies are more-or-less intact bodies (since they can usually be dispatched by destroying their brainpan), that means only a well-preserved body isoing to start moving.