03/01/2026
When and for how long should I irrigate my St. Augustine Grass?
Among all of the grasses in Florida, St. Augustine seems to be the most finicky and problematic grass of all the species. Usually, the problem is with the irrigation and the aspects that come along with it.
The University of Florida states that there are three main characteristics of an irrigation plan for St. Augustine: Frequency, Duration and Time. If these three items are being properly attained, then the resulting turfgrass will be thick, strong, green, and vigorous, and will combat insects, w**ds, and wild grasses more easily.
University of Florida states:
“A properly irrigated grass plant is better able to withstand pressure from w**ds and insects. W**d problems in a lawn indicate that the turf has been weakened by improper management practice. Proper management practices can eliminate most w**d problems.”
Proper irrigation in addition to a standardized Turf Treatment Schedule will provide optimal results for healthy grass.
Q: How Often Should I Run My Irrigation System? [Frequency]
A: For an already healthy lawn, two – three times per week*.
During the summer months, healthy St. Augustine can only go 1 to 5 days between irrigation events, based on the heat index (Myers & Horn, 1969). Weakened turf needs even more water.
*Always follow Local and State laws in regards to watering restrictions. As of July 2010, Florida residents can use automatic sprinklers 2x / week. Hand-watering hot spots or weak lawns may be necessary. Hand-watering is NOT prohibited, so long as it is after 6pm or before 8am.
Q: How Long Should I Water For? [Duration]
A: Spray Zones at 30 minutes, Rotor Zones at 45 minutes
The exact answer to this question is “½ to ¾ inch of water per irrigation event” (UF IFAS, 1999), but depth is harder to define than duration.
In an irrigation system with optimal pressure and proper coverage, the times listed above should provide the correct depth of watering. If you are following the above Frequency and Duration and still have “hot spots,” you may need to have your Sprinkler System checked by a professional.
Q: When Should I Water My Lawn? [Time]
A: The best time is in the early morning hours (1:00am to 3:00am), prior to the dew.
Watering in the late morning may be detrimental if it extends the time the lawn is naturally wet from dew, which may accelerate disease issues. Watering during the day wastes water due to excessive evaporation from the sun. Watering in the evening can lose just as much water to evaporation from the heat the earth gives off as it cools.
