You can find my comments on how to fertilize in
this thread. The reason fertilizing works is that it vastly increases the numbers of plankton available for very small fish to forage on. This stimulates the base of the food web and results in increased biomass (i.e. more/bigger bass)in your lake. In southerly latitudes, there really is no compelling reason not to fertilize, unless you have a vegetation problem. In that case, you would need to treat the vegetation, then begin a fertilization program.
Be careful not to overfeed if you are also fertilizing. Waste feed, in conjunction with a plankton die-off, could cause problems with low dissolved oxygen in your lakes.
As for the crappie, I would avoid them completely. Go with a proven combination of species, and you will be well on your way to good fishing.
