What Causes Fungus in Grass?

There are several causes of lawn fungus, most of which are just the result of poor lawn care practices.

Below I provide more details about each cause, with my experience treating the fungus for each scenario.

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1. Excessive heat and humidity

To reiterate, fungus occurs when your lawn is under stress, such as if you overwater, including excessive rain, or if your lawn is under water, and/or during times of drought.

Heavy watering and long periods of rain leave water on the surface of grass blades. Mycelia (the root-like structure of a fungus) use this accumulated water as a path to travel from leaf to leaf, spreading the fungus along the way.

Using your lawnmower or even walking on the grass when you are fighting fungus can help spread the fungus throughout the lawn.

2. Malnutrition

As a homeowner, you probably already know proper fertilization practices, but many of us still make the big mistake of over- or under-fertilizing, resulting in brown edges and/or fairy ring disease.

A general rule of thumb is to apply nutrient-rich fertilizer 4 times a year to your lawn. However, it is important to perform a soil analysis to Determine the proper amounts of nitrogen fertilizer or other types of food for your lawn. But be sure to perform a soil test first before applying any. fertilizer for your lawn.

And remember, fertilizer is not the only source of nutrients for your lawn. There is also rainwater or sprinkler water that helps the grass absorb essential nutrients such as nitrogen that is already present in the soil.

The faster nitrogen is depleted when it rains or when you water, the faster it will need to be replenished or else fungus will develop on your lawn.

3. High night temperatures

If nighttime temperatures are as high as daytime temperatures in your area, it could encourage lawn fungus to develop and thrive.

While there is not much you can do in this situation and I cannot advise you to water your lawn at night as this may provide the right conditions for fungus to grow, you should be aware that this could be a possible reason for the growth of fungus. fungi in the grass.

4. Poor airflow

Lawns with poor or restricted airflow are more likely to develop fungus. Good airflow reduces humidity levels much faster than stagnant air.

Poor air circulation can be caused by nearby privacy fences, buildings and dense trees and can increase fungal activity in lawns, surrounding garden sheds, above ground pools and outdoor furniture.

5. Compacted soil

Compacted soil affects the flow of water penetrating the roots, which can cause root diseases, including fungal growth.

In addition to an infected lawn, soil compaction can also cause weak, thin turf that is prone to weeds and pests.

There are many issues that can cause soil compaction, including poor soil structure. Sometimes soils can become compacted due to an inherited problem and will need to be addressed a little differently.

How do lawn fungi spread?

Lawn fungi spread easily and quickly in several different ways, including rain, wind, grass clippings, and even lawn mowers.

This is perhaps one of the main reasons why lawn care professionals avoid mowing fungus-infected grass without treating it, as the fungus can spread to neighboring lawns.

To prevent the spread of fungus in their lawn, many homeowners wait out the infestation in hopes of getting rid of it on their own. But failing to take action against grass fungus, such as applying fungicides or improving nitrogen levels, can be detrimental to grass health in the short and long term.

Before you leave…

I’ve written a detailed article on the most common types of lawn fungus and their remedies, and the list includes fairy ring, dollar spot, powdery mildew, snow mold, and red thread.

Also, check out my article on the best lawn fungus treatment. I offer more details on how to get rid of fungus with herbicides or using natural methods.

Hello, Alex Kuritz here. When I was a kid, I remember my family had one of the best lawns in the neighborhood. Richly green and lush. Growing up, I did a lot in terms of tending and caring for not only my family’s lawn but also my neighbors’ lawns. I can say that I have years of experience and I am here to share it with you.