St. Augustine is a fast-growing, hardy, warm-weather grass with a deep green color. It is best grown in zones 6 through 11. This is not a particularly drought-tolerant grass, and it does not hold up well to repeated traffic, but it does fill in nicely, forming a dense, rich green carpet. Once established, caring for your St. Augustine grass is relatively simple.
Water your St. Augustine grass whenever weather conditions begin to dry out your soil. Water a minimum of 1 inch with each watering. The soil should be damp but not soggy most of the time. Depending on temperature and wind conditions (wind dries lawns quickly), St. Augustine grass may need to be watered multiple times per week during the driest and hottest part of the season.
Fertilize your St. Augustine grass twice each year--at the start of the growing season and again at the end of the growing season--with a fertilizer high in nitrogen content. Apply 0.5 pound of nitrogen per 1,000 square feet of lawn. To determine how much nitrogen your fertilizer contains, divide 0.5 by the first number in your fertilizer's content ratios. For example, if you buy a 20-5-5 fertilizer you would divide 0.5 by .20 and get 2.5,which translates to 2.5 pounds of fertilizer per 1,000 square feet. Water your fertilizer into your lawn, applying at least 1 inch of water to your grass.
Add 1/2 as much phosphorus to your St. Augustine as you do nitrogen on the same schedule.
Mow frequently. St. Augustine is a fast-growing grass and must be mowed to a height of 3 to 3.5 inches once every five to seven days during the warm growing season in order to look its best.