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Common St. Augustine Grass Problems

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St. Augustine grass is often used for lawns in warm climates. Like most varieties of grass, St. Augustine grass comes with a unique set of problems that can affect its health. St. Augustine grass can experience problems with seeding, its environment and pests. Problems with St. Augustine grass can be diagnosed and fixed by carefully observing grass symptoms and using the correct techniques to treat the problems.


Overgrown thatch is a common problem in St. Augustine grass lawns. Thatch is a layer of organic material, like stems and dead roots, that accumulates in a patch of grass. Overgrown thatch is often characterized by large, unhealthy brown areas of the lawn. If the thatch in a grass patch grows to more than 1/2 inch thick, it can prevent live grass roots from reaching nutritious soil, causing it to root in the thatch itself.

In "Thatch and How to Manage It," The University of Illinois Cooperative Extension Service said that thatch is often be caused by fertilizing the grass with too much nitrogen. Address thatch in St. Augustine grass by aerating and topdressing the lawn. When you aerate the lawn, you poke large holes in it that break thatch apart and help loosen and add drainage to the soil. After the soil is aerated, you add a thin layer of lawn soil to help break down the organic buildup.


Beetle larvae appear as grubs which eat the roots of St. Augustine grass. Grass infested with beetle larvae will slowly turn brown over the period of about a year and the layer of deadened grass will lift easily from the ground. Because grubs reside in the root area just beneath the green leaves of a lawn, grubs are treated by drenching the damaged grass and its surrounding area with insecticide for grubs, with careful attention to the potency and amount of insecticide used.


Some types of worms are helpful contributors to a grassy ecosystem, while others are harmful to the health of a lawn. Sod webworms and cutworms are two types of worms that can damage a lawn. A worm infestation is characterized by skeletonized leaves, dead patches that vary in shape and size, and a web-like coating on the lawn in the morning. Chemical and biological controls are used to address problems with sod webworms and cutworms in St. Augustine grass.


St. Augustine seeds root poorly and fill in at a moderately slow rate. Because of these characteristics, St. Augustine grass is rarely planted by seed. St. Augustine grass is most successful when installed as sod.

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