I always water after spreading fertilizer too. I also have centipede grass here in south GA. The extension agent said that centipede needs very little fertilizer, if any at all, and it can do more harm than good if you apply it too often.
When I first moved to this house the yard was a mess and I fertilized it two or three times and in the bare places more than that the first year. It grew very thick and green and needed mowing twice or three times a week. It looked great but I got tired of mowing (2 acres). It's supposed to be cut about an inch and a half high and it's not supposed to be dark green like other lawns. The next year I didn't fertilize at all and I didn't water it nearly as much and it looked like the devil again before fall. The agent said a lot of fertilizer and water makes it much more dependent on water. If pretty much left alone centipede will dry out and turn brown during dry spells but will green right back up with some rain. It is supposed to be a very low maintenance lawn.
