Welcome to Garden.org,
@PlantMania !
I live much further north than you, but the general rule for harvesting garlic remains the same -- when there are only 3 or 4 green leaves left on the garlic plants, you should harvest them. Each green leaf represents a layer of "wrapper" around the garlic bulb; if you wait until the top dies completely back, you will have a bunch of individual cloves to try to dig up.
@DrDawg grows (and sells) garlic in Mississippi and may be able to tell you more about the actual timing of when yours should be ready to harvest; I believe he is going to be harvesting his garlic quite soon.
