Dig holes at least 3'x3'x3', fill 'em with a quality organic potting soil. No "time release" nutes or Miracle grow moisture control crap. Add a teaspoon of lime per gallon of medium, if you have any question of ph flucuation. Bone meal, blood meal are no-no's, too. Animals can smell them and will dig 'em up looking for the food source.
I've had good luck useing guano's, worm castings and/or alfalfa meal as additional supplements.