If you use common sense in caring for St. Augustine grass, you will be rewarded with a quick-growing, blue-green, dense lawn cover that resists weeds. St. Augustine doesn't like to be subjected to a lot of traffic; it doesn't like either dry or wet conditions; and it doesn't take well to over-fertilizing. Therefore, take an adaptable approach to watering and fertilizing, based on the particular needs of your lawn. With care, St. Augustine will tolerate salt, heat and shade.
Inspect grass for thatch, looking between grass blades in the spring. (Thatch is organic matter that doesn't fully break down into soil.) Rake the grass vigorously if the thatch has built up more than a half-inch. Do this when soil is dry and the grass is in the growth stage.
Mow often enough to keep the grass at a height of 2 or 3 inches. In spring, start off mowing low, then gradually increase the height increase as the weather gets hotter.
Water regularly, but only so that your grass gets about a quarter-inch of water, including rain, every week. A can placed in sprinkler range can help you keep track of how much you have watered.
Apply fertilizer up to three times while the grass is actively growing, doing so in early spring, early summer and late summer. Don't fertilize during droughts or excessive heat.
Test soil samples from your lawn through your county extension office every two years to make sure the soil pH is between 6 and 7, which is what St. Augustine grass prefers.
Adjust the pH if it has fallen below 6 by adding lime to the grass, then watering it.
Treat the lawn with pesticides according to package directions if chinch bugs invade. This common threat to St. Augustine grass tends to show up in hot, dry weather, creating yellow spots before killing the grass.