# Mowing Height on Tall Fescue



## dwightevansjr71 (May 20, 2020)

I was talking to another member and they recommended I reduce the cutting height of my lawn. I have tall fescue. It isn't drooping over or anything. I have been cutting to a height of 4.5" (as per the SCAG deck height). I am battling brown patch fungus (along with everyone else in my neighborhood). My question is, what is the consensus on optimal mowing height? And should I deviate from that if I am dealing with brown patch fungus? If so, is that deviation higher or lower? I am currently using Headway G and my yard has rebounded nicely over the past 4 weeks. I plan to continue applying Headway G every 28 days until SEP-OCT timeframe.


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## CarolinaCuttin (Sep 6, 2019)

dwightevansjr71 said:


> I was talking to another member and they recommended I reduce the cutting height of my lawn. I have tall fescue. It isn't drooping over or anything. I have been cutting to a height of 4.5" (as per the SCAG deck height). I am battling brown patch fungus (along with everyone else in my neighborhood). My question is, what is the consensus on optimal mowing height? And should I deviate from that if I am dealing with brown patch fungus? If so, is that deviation higher or lower? I am currently using Headway G and my yard has rebounded nicely over the past 4 weeks. I plan to continue applying Headway G every 28 days until SEP-OCT timeframe.


It might look better right now if you drop it down, but you'll have deeper roots, and a healthier plant that's more likely to make it through summer if you don't. Period between winter and fall and winter and spring are the times you can lower the height for a better look, I'd let it stay long. Nothing sucks worse than having to sling down more seed every year.

Edit: You're in Alabama, it's not even a discussion you need to keep it high lol.


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## dwightevansjr71 (May 20, 2020)

CarolinaCuttin said:


> dwightevansjr71 said:
> 
> 
> > I was talking to another member and they recommended I reduce the cutting height of my lawn. I have tall fescue. It isn't drooping over or anything. I have been cutting to a height of 4.5" (as per the SCAG deck height). I am battling brown patch fungus (along with everyone else in my neighborhood). My question is, what is the consensus on optimal mowing height? And should I deviate from that if I am dealing with brown patch fungus? If so, is that deviation higher or lower? I am currently using Headway G and my yard has rebounded nicely over the past 4 weeks. I plan to continue applying Headway G every 28 days until SEP-OCT timeframe.
> ...


Sounds good. I was just wondering. I'm gonna cut it tomorrow and put down the next round of fungicide and do some post emergent work. Another question. I really believe that Poa Annua I have came from the Rebel Seed I used. It is so evenly spread through my yard it had to be the seed. Here can I get quality grass seed from when I'm ready to plant in the fall?


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## CarolinaCuttin (Sep 6, 2019)

@dwightevansjr71 If the bag tag had any labeled weed seed that's definitely a possibility. There's so much Poa seed always floating around we definitely can't be sure it didn't come from the air or ground.

I buy my seed from Southern Seeds. They have a fantastic fescue blend called Triple Threat that really performs well in southern heat. They are located in NC but they will ship. I have experience with Triple Threat as well as their Pure Sport Perennial Ryegrass and can attest to the quality.


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## j4c11 (Apr 30, 2017)

I prefer to maintain fescue at 3", even 2.5". I found that cutting taller results in the grass staying damp for long periods of time, resulting in disease. It also looks neater imo, overly long grass tend to just plop over.

Headway G is good, but very expensive. Look into acquiring liquid propiconazole and azoxystrobin and save a boatload of money.


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## Chris LI (Oct 26, 2018)

If you decide to drop it a little, I would do it incrementally one notch at a time, maybe 
once per week and increase your mowing frequency by once more per week, to not stress the grass going into the summer. IMHO, I wouldn't go much shorter than one notch below the 4.5" anyway, as @CarolinaCuttin makes a good point.

If you want to be a little lower during the season, it's best to start early for the grass to adjust to the new HOC before the spring flush and summer heat hits...and keeping the blades sharp, goes a long way to reduce pathogens from entering the plant through the leaf tips.


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## j4c11 (Apr 30, 2017)

There's minimal stress on the grass going from 4.5" to 3.5" in one go. Even from 4.5" to 3". It's within the 30% rule, and that's what you'd be doing regularly with every mow.


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## dwightevansjr71 (May 20, 2020)

CarolinaCuttin said:


> @dwightevansjr71 If the bag tag had any labeled weed seed that's definitely a possibility. There's so much Poa seed always floating around we definitely can't be sure it didn't come from the air or ground.
> 
> I buy my seed from Southern Seeds. They have a fantastic fescue blend called Triple Threat that really performs well in southern heat. They are located in NC but they will ship. I have experience with Triple Threat as well as their Pure Sport Perennial Ryegrass and can attest to the quality.


I will look into Southern Seeds. Thanks.


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## dwightevansjr71 (May 20, 2020)

j4c11 said:


> I prefer to maintain fescue at 3", even 2.5". I found that cutting taller results in the grass staying damp for long periods of time, resulting in disease. It also looks neater imo, overly long grass tend to just plop over.
> 
> Headway G is good, but very expensive. Look into acquiring liquid propiconazole and azoxystrobin and save a boatload of money.


Yes, it is very expensive. Can you recommend a liquid alternative?


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## j4c11 (Apr 30, 2017)

dwightevansjr71 said:


> Yes, it is very expensive. Can you recommend a liquid alternative?


Certainly. Headway is a mix of propiconazole and azoxystrobin.

Propiconazole: https://www.domyown.com/propiconazole-143-p-16567.html
Azoxystrobin: https://www.domyown.com/azoxy-2sc-select-p-15183.html

It's good to know that azoxystrobin is used in agriculture as well. So, there's formulations that are identical to Azoxy 2SC, exactly same product, but much cheaper per ounce. But these products are not labeled for use on lawns. But they're identical and much cheaper. And so if you needed to spray say same some grapes and/or peanuts with azoxystrobin, you could buy something like this:

https://www.keystonepestsolutions.com/index.php?main_page=product_info&products_id=320&utm_source=google&utm_medium=cpc&adpos=&scid=scplp320&sc_intid=320&gclid=CjwKCAjwq832BRA5EiwACvCWsWydkN0HyL8lSl_ngtUo65sBHDIBeoNWOSybsP02slygMh6ebuwxcRoCOMEQAvD_BwE

So while it's a bit of an upfront investment, your cost per thousand sq ft is 90% less vs Headway.


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## dwightevansjr71 (May 20, 2020)

j4c11 said:


> dwightevansjr71 said:
> 
> 
> > Yes, it is very expensive. Can you recommend a liquid alternative?
> ...


I did some research....Azoxystrobin is $125.00 for 16oz and Propiconazole is $50.00 for 32 oz. Azoxystrobin is .77 oz per 1000 SQFT and Propiconzole is 2 oz per 1000 SQFT. I have a 13,000 SQFT lawn. Which means I need 9.75 oz of Azoxy and 26 oz of Propicon per application, per 28 days. I have a 4 gallon back pack sprayer and it typically takes about 5-6 gallons of water to complete the whole yard. Does this sound about right? I wish the labels just said ??oz per gallon of water.


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## j4c11 (Apr 30, 2017)

dwightevansjr71 said:


> I did some research....Azoxystrobin is $125.00 for 16oz and Propiconazole is $50.00 for 32 oz. Azoxystrobin is .77 oz per 1000 SQFT and Propiconzole is 2 oz per 1000 SQFT. I have a 13,000 SQFT lawn. Which means I need 9.75 oz of Azoxy and 26 oz of Propicon per application, per 28 days. I have a 4 gallon back pack sprayer and it typically takes about 5-6 gallons of water to complete the whole yard. Does this sound about right? I wish the labels just said ??oz per gallon of water.


Ok, that's a lot of lawn.

The most cost effective versions of these fungicides are:

PPZ 41.8 (41.8% propiconazole). This is almost 3 times more concentrated than the 32oz/$50 so about 1/5th of the price per thousand sq ft.

https://www.domyown.com/prime-source-ppz-418-fungicide-p-12192.html

Abound (22.9% azoxystrobin). Approximately 1/5th the price per thousand sq ft vs the 16oz/$125.
https://www.keystonepestsolutions.com/abound-fungicide-1-gallon-320

As an example, with the above products, your cost per thousand would be approximately $2, or $26 for your entire lawn per application. About 90% less vs Headway G. Always read the label before use to make sure you're complying with all rules and regulations.

The reason the rates aren't in oz per gallon of water is because everyone's sprayer is different. My back pack sprayer setup puts out 4 gallons over 2,500 sq ft, sounds like yours puts out 4 gallons over about 10,000 sq ft. What's important is the amount of fungicide per thousand sq foot of area, not the amount of water it gets diluted in.


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## dwightevansjr71 (May 20, 2020)

j4c11 said:


> dwightevansjr71 said:
> 
> 
> > I did some research....Azoxystrobin is $125.00 for 16oz and Propiconazole is $50.00 for 32 oz. Azoxystrobin is .77 oz per 1000 SQFT and Propiconzole is 2 oz per 1000 SQFT. I have a 13,000 SQFT lawn. Which means I need 9.75 oz of Azoxy and 26 oz of Propicon per application, per 28 days. I have a 4 gallon back pack sprayer and it typically takes about 5-6 gallons of water to complete the whole yard. Does this sound about right? I wish the labels just said ??oz per gallon of water.
> ...


After reading this, I may be spraying my lawn wrong. LOL But its all good, I am learning. How did you determine that your back pack sprayer puts out 4 gallons per 2500 SQFT?


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## j4c11 (Apr 30, 2017)

dwightevansjr71 said:


> After reading this, I may be spraying my lawn wrong. LOL But its all good, I am learning. How did you determine that your back pack sprayer puts out 4 gallons per 2500 SQFT?


Well, I've been using it for years, so I know exactly how fast to walk and how to spray to have it cover exactly the area I need.

But initially, when I bought it, I didn't know. There's two variables you need to account for, sprayer output and walking speed. If you walk faster you cover more area, and viceversa obviously. Strap the exact same backpack sprayer onto the back of a shorter person and you might get different results as well, because their gait is different.

So I did two things. First I sprayed into a measuring container for 15 seconds. I think I used an old herbicide bottle with fl oz markings. That gave me the sprayer output in fl oz per minute. Then I put the sprayer on my back and, at a speed that was comfortable to me, I sprayed my driveway with clear water, top to bottom, while timing the operation. I did cement instead of grass because it's real easy to see where you already sprayed. The two together gave me fl oz per thousand, and I remember even on my first use of the sprayer I was pretty spot on.

So let's say - I'm making these numbers up - the sprayer put out 8 fl oz in the measuring container in 15 seconds, meaning 32 fl oz per minute. Let's also say, it took 6 minutes to do 1800 sq ft of driveway. That means 3.3 minutes per thousand sq ft. Put the two together, it will take 32 fl oz * 3.3 = about 105 fl oz per thousand sq ft, just under a gallon.


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## nclawnguy (Jun 27, 2017)

Unfortunately brown patch on fescue in the south is a common problem. The good news is Heritage (azoxystrobin) work awesome as a preventative and a cure. I'll usually go back to back applications 28 days apart then alternate with something else, usually propiconazole. Its going to get hot and muggy this week, you'll start to see lots of fescue lawns start to struggle.

On the mowing height question, I keep it high in the summer, 4-4.5".


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## LeftField11 (May 24, 2020)

j4c11 said:


> Abound (22.9% azoxystrobin). Approximately 1/5th the price per thousand sq ft vs the 16oz/$125.
> https://www.keystonepestsolutions.com/abound-fungicide-1-gallon-320


This is why I browse every thread, even ones that appear to have nothing to do with my KBG lawn. That's a great find, @j4c11


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