The best way to maintain a healthy, weed-free lawn is to provide routine fertilizer applications throughout the growing season so the turf can compete against weeds and recover from stress. Different fertilizer combinations should be applied at different times for different types of growth. To ensure a beautiful lawn, be sure to apply the appropriate ratios at the appropriate times. Typically, spring is the time to fertilize to promote growth. Late fall is the time to promote good root growth and to prepare for winter.
You can find out much more about caring for your lawn at the following resources provided byClemson University Cooperative Extension Service websites:
Centipede Grass: http://www.clemson.edu/extension/hgic/plants/landscape/lawns/hgic1215.html
Bermuda Grass: https://www.clemson.edu/extension/hgic/plants/landscape/lawns/hgic1216.html