Lawn fungus

Lawn fungus

What is lawn fungus?

Most fungi in lawns can actually be healthy to some grasses. They decompose organic matter, which releases and then supplies turf nutrients that are good for their growth. Fungi belong in the turf and if properly maintained, they can be part of the reason why a lawn is beautiful. 

Dormant harmful microorganisms and disease-causing lawn fungi are almost always present in the soil. They are just waiting for the right condition to be active and make the lawn disease come out. They are like silent enemies, looking for the perfect time to attack, most commonly when your turf is under stress. 

Fungus is a disease resulting from changes in weather condition and temperature, extended period of moisture either due to improper irrigation, slopes or uneven ground, and high heat can make grass susceptible from diseases as they reduce grass’ ability to fight infections. Wet and humid is the kind of weather that allows fungi to really start to creep to your lawn. 

How does it spread?

Fungi are spread by wind, rain, grass clippings, and even by lawn mower. This is why lawn professionals do not mow a lawn infected with fungi without it undergoing treatment as they might spread the disease to their other customers’ lawns. It can even be spread by walking through the infected area and then across your lawn, especially when it is wet. Fungi really loves damp and moist environments. 

Sometimes you can see lawn fungus, sometimes you can’t. Whether you see it or not, it is just around us, including your lawn! Fungi only becomes noticeable once the disease comes out. You may discover patches in various shapes, sizes and colors. It starts as yellow, tan, or brown of varying sizes in the lawn. It consists of rings that grow over time with a difference in diameter and will quickly fill your lawn with patches. Fungi might also appear as mushrooms.

How can you prevent it?

Once fungal disease hits your lawn, identifying the lawn and grass diseases and understanding the causes behind them is essential for its treatment. Not all lawn fungal diseases are treated the same way. You might treat one type one way but might worsen the other. This is why you need to identify the cause of the problem, the problem itself, and then choose the correct treatment to save your lawn. It is usually better to consult a lawn profesional than to treat your lawn by yourself which could worsen the situation. 

The tricky part is, over or under watering and too much fertilizer or lack of, and using the wrong amount of chemical can result in a lawn fungal disease. Even a compacted soil and wrong type of grass, and either long rainy seasons or drought, can cause lawn fungus to dominate your lawn. Don’t panic yet, maintaining proper care with your lawn can go a long way, which can save you from this stress!

Proper watering

There is a thin line between hydrating your lawn and encouraging fungus to grow. Proper watering includes giving your lawn the right amount of water and watering at the most appropriate time. 

The best time to water your lawn is early in the morning, between 6am – 10am. This is the perfect time to soak your lawn and allow the sun to dry the lawn throughout the day. Watering in the evening will leave you with a wet lawn overnight, which is the ideal condition for fungus to grow.

The rule of thumb is you need to water your lawn deeply by giving at least one to one and a half inches of water per week (including the rainfall, if any) to soak the ground sufficiently, depending on your type of grass. 

Watering your grass deeply will help the roots elongate and are able to absorb more nutrients, moisture, and oxygen. Lawns with sufficient moisture will develop deep root systems which help your grass to thrive and avoid fungus and diseases.

Choose the right grass for a given location

It’s very important to plant the right grass for the right area. You should consider the climate in your region and the type of ground your grass will cover when choosing the grass you want to grow. Is the area a shady one or one that gets too much sunlight everyday? 

You must plant a shade-tolerant grass in shaded areas to ensure healthy growth and a sunny seed for the latter. A shade seed planted in a sunny area will work. It will still germinate and sprout, but then, it gets weaker over time, allowing fungus to take over until you have a dead grass in your lawn.


As a preventative measure, do not cut your grass too short. Cut your grass at the recommended height for your variety of turfgrass. Longer grass blades will get as much sunlight as needed and shade the ground which can possibly cause weeds to sprout that will eventually compete with the grass in taking nutrients. However, if fungal disease is already present, make sure to have a catcher on your mower to bag the clippings until the disease clears up to avoid the fungus or spores from spreading. 

Avoid using a dull mower blade in mowing grass as it will shred grass tips and provide an entry point for infection. Another way to prevent the fungus from taking hold is to get some airflow into the ground. You can take your blower or mower early in the morning and dry your lawn off.

Apply fertilizer or fungicide

The easiest remedy is to feed your lawn with an organic, slow-release fertilizer. Specific fungus like Dollar-spot, needs nitrogen to be cured, so you can use a nitrogen-blended fertilizer to fix the issue. Other options include applying or spot-spraying fungicide to infected areas. 

You can use a liquid or granular type. The recommended time to apply fungicide is in late spring or early summer. Make sure to follow the instructions on the label for how to apply it. You will have to do three applications with a seven to 14 day interval between each one. This will work well for your first year of applying fungicides. If it is your third or fourth year, you might need to have a fungicide rotation program as fungus must have become resilient by now.

As we have mentioned before, maintaining proper lawn care is the best way to protect your lawn from diseases and have a healthy grass that out-competes any fungus. If the problem is already existing, go ahead and apply necessary curative fungicide.

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