A layer of thatch is generated when partially decomposed plant components pile up on the soil’s surface, restricting the circulation of air, water, and fertilizers in the soil.
Thatching rarely affects St. Augustine grass lawns unless they were previously over-fertilized and mowed infrequently. Because thatch-related problems with St. Augustine grass lawns are uncommon, dethatching these lawns is a hotly discussed topic. Our guide looks deeper at whether you should dethatch St. Augustine grass or leave it be.
By the end, you’ll be armed with more information on dealing with St. Augustine grass thatch if you decide you need to dethatch St. Augustine lawns. Either way, you’ll see the best ways to care for your lawn if you have beneficial thatch buildup or your St. Augustine lawn looks and grows better without it. (Learn How To Make St Augustine Grass Spread Quickly)
Is It Okay To Dethatch St Augustine Grass?
The layer of dead plant material that falls on top of the soil is thatch. Most thatch comprises dead grass clippings that accumulate throughout the summer, but they can also comprise dead leaves, pine needles, and other plant material.
It is beneficial to your lawn if the thatch is less than 1/2” deep.
A thin coating of decomposed plant debris will help retain moisture, and the leaves will restore nutrients to the soil as they decay. As the organic material decomposes, black, crumbly topsoil forms, choking off weeds.
Thatch will only break down on a healthy, well-maintained lawn and, like compost, only degrades if your lawn is damp, warm, and aerated.
Here you can see how to control your thatch layer at a manageable height:
- Irrigate your lawn deeply with an infrequent irrigation schedule. Once per week, water for 45 minutes to 1.5 hours to moisten the soil and keep the thatch moist.
- In the spring, use a core aerator. Aerating the soil introduces oxygen, which feeds the microbes that break down the dead vegetation.
- Follow the rule of 1/3rds and use a mulching blade. Thatch breaks down faster into partially decomposed plant material when grass clippings are small. Regular mowing twice per week with a mulching blade helps. Also, never cut off over 1/3rd of the growth.
You can encourage decomposition by modifying your lawn care techniques if you already have a few inches of thatch buildup on a properly maintained lawn.
After a growing season of proper care, you can avoid dethatching St. Augustine grass with a power dethatcher, as power rakes aren’t recommended.
When Should I Dethatch My St Augustine Grass?
The development of dead plant material at the base of the St. Augustine grass blades causes thatch. Grass clippings, decaying leaves, and even little twigs make up the dead plant material. Because it grows via above-ground runners called stolons, St. Augustine grass is less prone to thatching buildup than most other varieties of sod-forming grass.
When to dethatch St. Augustine grass
Dethatching St. Augustine grass is best done in the mid to late spring when the grass has emerged from hibernation and grows. Spring will see your grass growing vigorously and allowing the grass to reach a safe mowing height quickly. (Read Is Spray On Grass Seed Worth It)
Before using a dethatching rake, mow the lawn to make removing thatch closer to St Augustine lawns’ soil easier.
Because St. Augustine turfs grow actively until late summer, dethatching in the spring allows them to recover.
Dethatching St. Augustine grass later than a July time frame and reaching into the fall isn’t wise as the grass will not recover from the stress of dethatching during the cool season.
Dethatching your lawn during the cooler months, you’ll most likely end up with dead and bare places.
The type of St. Augustine grass you’re growing is the most important aspect to consider for dethatching frequency. Some cultivars require dethatching at least once a year, while others can take up to two years to develop heavy thatch that causes dethatching.
Because a thatch rake does not hurt the stolons, it can be used for most of the growing season, but you should still allow enough time for a modest layer to form before dormancy.
Why Not To Dethatch St. Augustine Grass?
A power rake can be set to two settings: a wide setting for bunch grass and a small setting for sod-forming grass. Most sod-forming grasses use Above-ground stolons and below-ground rhizomes.
The grass will recover from the rhizomes below if you cut through and eliminate most of the runners above ground.
Use equipment that successfully remove thatch while causing minor damage when dethatching St. Augustine grass. Hand rakes and vertical mowers are two examples.
When dethatching a St. Augustine lawn, avoid using a power rake because it can cause considerable damage to root development that takes a long time to repair.
How to dethatch St. Augustine grass:
Here are some things to remember when you want to get rid of thatch from your lawn.
Water 24 hours before dethatching
If you have a hard-packed thatch layer on your St. Augustine lawn, water it 24 hours before dethatching it.
Watering relieves stress on the grass and helps it recover faster. Remember to dethatch only damp soil. Over-watering can make your yard muddy, attracting fungus in St. Augustine grass.
Mow St Augustine lawn at 2 inches
Before you dethatch your St. Augustine lawn, mowing St Augustine makes it easier for the dethatcher to reach and pull away from such a thick layer of thatch beneath the living grass blades.
Cut the grass at a low blade height of 2-inches when dethatching St. Augustine. You’ll be able to give the dethatching tool ample access without cutting off too much of the stolons at this mowing height, preventing severe lawn damage.
Dethatch your lawn
Because using a power rake to dethatch a St. Augustine lawn isn’t suggested, we cover how to dethatch St. Augustine turfgrass with a vertical mower or a manual thatch rake.
Verticutting or vertical mowing uses a vertical mower on warm-season grasses to cut through a thatch layer. (Find the Best Fertilizer For St Augustine Grass)
A vertical mower looks like a standard lawnmower but has vertical blades, tines, or prongs instead of a single horizontal blade.
These blades draw thick layers of yet to be decomposed plant material to the surface of the lawn, making collecting easier.
When using a vertical mower to dethatch St Augstine grass, set the vertical blades 3 inches to a narrow setting and pass over the grass once. Do not go over the exact location more than once, even if you have excessive thatch.
These two precautionary procedures can help keep your St. Augustine lawn in decent shape. After you’ve removed the excess thatch, use a hand rake to remove the loose thatch off the surface of your Augustine turf.
Only use a hand rake or a thatch rake to dethatch a small yard (no larger than 1500- square feet). Hand raking takes time and effort.
The best and easiest way to dethatch is with a hand rake, even on uneven turf. The rake can easily access regions where a verticutter or power rake cannot.
While experts agree that up to 0.5 inches of thatch are healthy to St Augustine grass, St Augustine grass will grow better if you remove this, so a new layer can form rather than the thatch layer being too compact.
Aerate your lawn
Aerate your lawn after dethatching to help the microbial life dissolve the new layer of dead material faster. In addition, Dethatching improves aeration because the core aerator machine doesn’t have to work through heavy thatch to reach the soil.
This helps St. Augustine turfgrass recover faster after dethatching.
Will Grass Grow Back After Dethatching?
Your lawn will be strained after dethatching. For several weeks, the grass will try to mend and fill in bare patches. Start your lawn off right by providing it with the nutrition it needs to heal.
Fertilize after dethatching. Your lawn has been starved of nutrients because of a thick thatch layer that acts as a filter. Applying a thin layer of slow-release fertilizer like Milorganite after dethatching and aerating your St. Augustine lawn can help your whole lawn have new turf vigor and green-up.
Less thatch means higher fertilizer absorption. Slow-release nitrogen fertilizer is excellent for spring lawn recovery. After removing thatch, keep mowing. Mowing increases lawn growth. Healthy roots make healthy lawns; therefore, dethatching is important after thatching.
Gradually increase mowing height to 4” but keep mowing every 4-5 days after dethatching to encourage new growth. After dethatching, enrich the soil. Poor soil can cause or has caused too much thatch buildup.
After dethatching, collect soil samples and carry out a soil test. Compacted soil inhibits the breakdown and incorporation of organic matter and plant debris into the topsoil. Apply compost at the start and end of each growing season to increase texture. (Learn How To Make St Augustine Grass Thicker)
A healthy St. Augustine grass is simple to maintain and much less expensive than using power rakes every early spring to deal with a thatch problem.