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How to Prevent Brown Patch in Cool Season Grass Types - Lawn Care Tips

By DoMyOwn staff

Brown patch in cool season turf is influenced by many things including but not limited to high heat and humidity, mowing height, and proper fertilization.

 How to Prevent Brown Patch in Cool Season Grass Types - Lawn Care Tips Video Play

Video Transcript

Hey I'm Heath from

Today we're gonna talk to you about Brown Patch Fungus in Cool Season turf. And what you can do to prevent that brown patch fungus from attacking your cool season lawn.

Whether or not your turf will be affected by brown patch fungus will be determined by a few factors. Humidity and air temperature along with mowing height and watering practices. And then in addition that, the time of year- so whether or not it's warm or cool outside would determine whether or not you would have brown patch fungus. 

The leading cause to brown patch fungus is high heat and high humidity. Anytime that your humidity and air temperature are added together and greater than 160,  it's ripe for fungus. That fungus really thrives in temperatures that are above 90 degrees during the day and 70 degrees at night. Usually this is gonna fall in the summer months - anytime between May and September, this is gonna be ripe for that fungus.

The other major leading cause to Brown Patch is turf wetness. Prolonged periods of wetness can cause brown patch fungus to spread, so you wanna make sure when you're watering you water early in the morning, so that you can have that lawn dry up and then you want dry-out periods in between your watering as well. That would depend on your turf type and your soil conditions whether or not you need to water every two days or three days.

Another important factor for brown patch fungus is your mowing height. You should check with your local county extension service to determine what your mowing height should be for your specific turf type. It will vary throughout the year whether it's Spring, Summer, or Fall for those specific turfs. In addition to that, if you have an active brown patch fungus, you want to make sure that you are bagging your clippings so that you're not spreading the disease throughout the entire lawn.

Another important factor to brown patch fungus is your fertilization program. You wanna make sure that for cool season grasses, you're not fertilizing during the summer months to encourage that brown patch fungus to come in. If you are gonna fertilize, make sure that you're using a low Nitrogen fertilizer or maybe an all-natural product or maybe even a liquid iron or a granular iron application to give yourself some color. Another important thing that you can do to help prevent disease in the lawn is to do an aeration in the spring or fall preferably for cool season lawns. This will alleviate soil compaction in those high traffic areas and allow the water to drain into the soil so that it's not on the surface leading to that brown patch fungus.

So let's talk about timing of treating that lawn. As a preventative measure, you wanna get ahead of the fungus before it would actually be active. So that would be when your air temperatures are greater than 60 or 80 degrees and your humidity is greater than 60 or 80 degrees as well.

Anytime that those two added together are greater than 160, you should be putting down a preventative fungicide for your cool season turf to prevent brown patch fungus. In addition to treating with fungicides, you wanna make sure that you're rotating your fungicides and not using the same FRAC code for each application.

You don't wanna do more than 2 or 3 applications with the same FRAC code in a row before you rotate to a different active. So if you need help determining what active you have, you can always call us at

We have a wide variety of different fungicides here at So if you ever need help making your selection for the type of fungus that you may have in your grass type, feel free to call us or email us at

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