St. Augustine grass is a common choice for lawns because of its low maintenance and quick growing cycle. It is also a hardy grass, which makes it ideal for hotter climates. Even the easiest of grasses, however, can become thin if not cared for properly.
Identifying the Problem
Check your yard to see if you can discover what caused the bare patch. Is the grass in a too shady area? Perhaps trees should be trimmed to allow more light to filter through. Over or under watering can also cause bare patches. Grass should be watered enough to completely soak the grass, but not enough to leave puddles of water for any length of time. Grass can also become choked by weeds or dead grass layers from winter or previous grass plantings. Treat the lawn with weed killer or other treatment to clear away competing plants. Fallen leaves can also cause grass to choke and die. Make sure to keep the lawn well raked and free of debris.
The best time to plant grass plugs or sprigs is during the spring when there is no danger of frost and the temperatures have not yet skyrocketed. The first part of repairing bare spots in any kind of grass is to eliminate all of the old, dead grass. A thatching rake can be used for this, and can be very effective at removing old and dead grasses. Make sure to pull up all of the old grass, including the roots. Dig holes for the plugs equaling about 6 inches square. Grass plugs are a lot like mini grass-sod squares and should be treated in a similar manner. Plant the plugs as soon as possible and keep them moist until they start to grow into the other grass patch. You can buy plugs at a garden supply store or you can create your own plugs from a well-covered area of the yard. Just be sure to dig deep enough to get the root system of the plant, otherwise the grass will quickly die out. Depending on the spacing between the plugs, grass can take three months to a year to fill in.
Other Repair Tricks
An alternative to grass plugs or sod is sprigging. This is a collection of tiny grass sprigs that can be planted into the soil. The bottoms of the sprigs should be covered with soil, but the tips of the grass blades should be exposed. Care for grass sprigs is the same as for plugs. Weeds should be vigilantly removed to prevent them from taking over the space where the grass should be growing and from stealing the grass's nutrients. Grass sprigs take anywhere from one to two years to fully grow in.