The best time to plant St. Augustine grass seed is from March until September. St. Augustine is considered a warm-season grass.
Warm-season grasses, such as St. Augustine, thrive in the warmer climates found in the southern United States. This warm-climate grass needs hot summer weather to thrive, and it cannot withstand northern-climate winters. Even with temperate winters, St. Augustine goes dormant during cooler winter months, so if year-round color is desired, St. Augustine grass should be interspersed with other types of annual grasses. St. Augustine is a coarse, creeping grass that should be mowed short and fertilized to keep it healthy and looking its best.