How to Prevent Red Thread in Lawn

How to Prevent Red Thread in Lawn

Red thread is a type of fungus that is quite common in lawns. The unsightly reddish-brown smears are often seen in between the grass blades of both cool and warm-season turf. It attacks several varieties of turf, regardless if it’s a sunny or shady spot.

While this disease is often unavoidable, there are specific conditions that favor the appearance of red thread.

This article will discuss some pro tips on how to prevent red thread in lawns and also how to get rid of the fungus once it infects your lawn.

Let’s dive in.

How to Prevent Red Thread in Lawn

1. Frequent Dethatching

Dethatching is the process of removing thatch from the lawn. Thatch is the layer of dead plant material (leaves, stems, and roots) located at or below the soil’s surface. It is a good practice to dethatch the lawn twice a year, in late spring and early fall.

Reducing thatch is essential because it’s often a suitable environment for fungi and other microorganisms to thrive. Frequent dethatching will also increase the drainage of water from the soil to the surface of the turf.

This will reduce disease pressure and prevent diseases like red thread from taking over your lawn.

2. Slice Seeding

Slicing is the practice of thin seeding a lawn. Thinning the grass does two things: it creates more open space between each blade for air circulation, and it reduces the shade that some grasses create for each other. Thinned seedlings will also grow faster because they get more sunlight.

Slicing will reduce the amount of thatch in your lawn, again reducing disease pressure. Thatch is not only good for fungi but also for pests like chinch bugs, so slicing will help your lawn resist them as well.

3. Disease Prevention Products

Several fungicides labeled for use on your lawn can help prevent red thread from infecting your grass. Take note, however, that these products merely cure a lawn already infected with the disease. Use them only to prevent it from getting worse.

Also, with these products, make sure to read the label and take note of when it is safe for you to apply. For example, some fungicides are not for use during periods of extreme heat or cold, as this may result in fewer benefits or even harm your lawn.

4. Using Good Soil

Fungal diseases live in the soil and infect your grass if they have a good place to grow. Good soil has the proper nutrients for healthy grass growth and a healthy amount of organic matter to help the soil “breathe.” Red thread thrives in soils that have low organic matter and nutrient content.

Sandy soils are perfect for this fungal disease, as the sand drains very fast and doesn’t hold moisture like other soil types, which is what red thread needs.

5. Mowing Short & Regularly

This is one of the critical steps for controlling red thread in lawns. Mow your grass short at least once a week and more often when needed. This will open the grass up to air circulation, allowing it to breathe better and help prevent disease pressure.

Taller grass has more shade and dense growth, which are necessary for red thread to live and have an excellent environment to spread.

6. Using Quick-Release Fertilizer

Red thread fungus cannot compete with healthy, growing grass. Feeding your lawn reduces disease pressure and helps your lawn grow faster. A quick-release fertilizer will provide needed nutrients for your lawn and will also get down deep in the soil.

Pro tip: Corn gluten meal is a natural organic product that can help prevent many fungal diseases by controlling the number of nutrients available on your lawn. It will also help control thatch, which is a suitable environment for the red thread fungus to thrive in.

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How to Get Rid of Red Thread in Lawn

1. Proper Fertilization

As mentioned in the preventative section, proper fertilization will help your lawn resist diseases. Using fast-release fertilizer, in particular, will give your lawn the nutrients it needs to produce more healthy grass capable of fighting off the red thread fungus. However, proper application can also help eliminate the Red Thread from the lawn.

2. Watering Appropriately

Watering your lawn 4-5 days per week will keep it healthy and less likely to get infected. Deep and infrequent watering is best. Deep watering will help your lawn get the water it needs in the root zone where fungus cannot live.

Also, watering infrequently will allow the soil to dry out between watering, which also helps prevent disease.

3. Aeration

Aeration is when you poke holes in your lawn with a machine that pulls plugs of soil out of the ground. This will help give your lawn the nutrients and oxygen it needs for healthy growth.

It will also help fluff up the soil and reduce compaction, which is another fungus-friendly environment.

Tow behind commercial lawn aerator

4. Thatch Control

While you don’t want to remove all thatch, excess thatch (which is layers of built-up grass) will give the red thread fungus a place to grow and thrive.

Thatch can also be a site for disease infection. Maintaining thatch at 1/3rd inch or less is ideal. Read more on what causes thatch in lawns.

5. Proper Seeding

Using good, disease-resistant seeds for your lawn will help your new grass establish itself as quickly as possible and resist red thread and other fungal diseases.

Although it isn’t likely that your new lawn will get infected with red thread, it is possible if you don’t use good seeds

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Best Fungicide for Red Thread

Red thread is considered a minor disease in the turfgrass industry. It doesn’t kill your grass. It just makes it unsightly and itchy for people to walk on. However, it spreads fast and may not be something you want on your lawn.

Fungicides should be used when the grass is actively growing, so the best time to apply is in early fall or spring.

Best Overall: Scotts Disease Ex Lawn Fungicide

Scotts Disease Ex prevents and controls red thread weed disease by stopping the infection in its tracks.

This fungicide is fast-acting and easy to spread, with long-lasting benefits, making it perfect for preventing this disease from spreading to other areas of your lawn.

Scotts Disease Ex is effective against more than 22 turfgrass diseases, including red thread disease. Others include brown patch, Northern and Southern brown patch, dollar spot, rust diseases, anthracnose, and needle cast. One of the best features of Scotts Disease Ex is that it is compatible with Scotts Turf Builder Starter fertilizer, so you can double up on your protection if you want.


  • Easy to use
  • Preventative and curative
  • Works on a wide array of lawn diseases
  • It lasts up to four weeks after application


  • It may be toxic to pets

Also read: What herbicide will kill poa annua in Bermuda grass

Best for All Lawn Types: BioAdvanced Fungus Control Fungicide

BioAdvanced Fungus Control works to prevent fungus and red thread disease from entering the soil by providing a protective layer around root zones, preventing seedbed contamination during establishment, and suppressing re-invasion in established turf after drought stress.

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Although it is a preventative product, it also provides quick curative control if the disease is already present.


  • Preventative and curative protection
  • Long-lasting systemic protection
  • Works on all lawn types
  • Rainproof


  • Slightly pricy

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How to Prevent Red Thread in Lawn (FAQs)

Will red thread go away?

Usually, this disease will go away as the temperatures get warmer. If you see infection on your lawn, you should apply fungicides to prevent it from spreading further.

What causes red thread in lawn?

Red thread is caused by the corticoid fungus laetisaria fuciformis, which often lives in dead organic matter. It is most commonly spread through infected soil or seeds, although it can also spread by wind or rain.

Does overwatering cause red thread?

Overwatering your lawn, especially when it is already wet, creates an environment in which red thread fungus thrives.
Red thread prefers to live in moist and dark conditions, so this may be the cause of your infection

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