# Summer 2019



## g-man (Jun 15, 2017)

We had a very wet spring in most areas of the cool season zone. Most of us are still without using the irrigation system this year. As we transition into summer (higher temps are showing up), a few areas of concern do pop up. I intend to update this thread thru the summer.


*Fungus*- This will be the main problem. Wet conditions with warm temps will promote fungus. Some lawns from members show some Leaf Spot in them. Dollar Spot will start to pop up too (my model hit 50% yesterday). Please look at the Fungicide Guide and have a game plan. This could involve a preventive treatment or a curative one, but have the materials at hand. This article from UNL discusses some of the diseases that show up in wet conditions.

*Denitrification* - The heavy and constant water lodge soils could develop a few issues. The main one is called Denitrification. In simple terms, it means that the nitrogen you applied could get lost to the air. It is rare in spring, but possible. The heavy water also causes lack of oxygen in the root zone. This causes the roots to be less effective at grabbing nutrients. The main one for me is chlorosis, lack of iron. Foliar iron, FAS, is the best way to get around this.

*A drastic weather change* - We like this rainy weather and start getting comfortable with "throwing down" fertilizer. But the weather could turn dry and hot in a couple of days. The nitrogen you applied ( and worst with slow release sources), will continue to feed and be available. I suggest going with every 2 weeks applications at half rate than monthly. This gives you the chance to hit the break pedal sooner.

Ensure you do an irrigation audit - This is the time to know how much your system needs to run to get you 3/4-1in of irrigation. Whatever the system it is (hose or inground), known is important. It helps you discover problems before it is too late.

 Fertilizer - While 1lb of N/ksqft/month is the max you could do, it doesnt mean that you should. A lower rate or none, makes the lawn use less water. If the weather becomes dry, then not pushing for grow will help the lawn survive more.

 Weed - As temperature increase, so does the potential to cause damage to your lawn with herbicides. Please read the label before use to check for restrictions.

 HOC - Height of Cut - I know this one brings strong emotions. A high HOC helps survives a strong sun/heat, but also does a dense turf stand. The spring rains helped a lot of us develop a dense lawn that looks great now, but too dense is also a recipe for more fungus problems (see the first bullet point). Find a happy spot for your lawn that provides some balance.


I hope these points help you have a great lawn during this summer


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## Pete1313 (May 3, 2017)

Great and timely post!


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## Killsocket (Mar 16, 2018)

Very informative! Thanks for all you do here g-man!


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## jha4aamu (Oct 16, 2017)

great info @g-man


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## Jconnelly6b (Mar 4, 2018)

Thank you G-man, very informative and timely.

I might add doing a sharpening or the blades after all the spring growth can help reduce the browning appearance as well as susceptibility to disease pressure.


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## synergy0852 (Jun 30, 2018)

@g-man Do you have a link to your Google sheet you've shared in the past where you track all this? I checked another thread the other day, but the link was down.


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## g-man (Jun 15, 2017)

Log thread

Let me know if it is not working. You need to save a copy for you once you open it.


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## synergy0852 (Jun 30, 2018)

@g-man It works. Looks different than the other day, below is what it looks like from my phone, might be an issue on my end. Snagged it from the drive Link. Thank you very much!


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## Green (Dec 24, 2017)

Two more things to add, @g-man...

-Along the lines of denitrification. On top of that, many Northern locations had an early, sustained cold, and lack of snow the first two thirds of the Winter other than a few early storms. The effect of this was a lot of the Fall topgrowth desiccated and burned off. That consumed a lot of the Fall Nitrogen to regrow in the Spring and took longer. I noticed the first signs of Nitrogen deficiency starting this past week, and plan to get my organics applied soon, in the next couple of weeks.

-Not lawn specific, but the extra rain is likely to induce a bumper crop of mosquitoes. Control is something people should be thinking about, even if they never have in prior years. We have a great pest control forum here.


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## SNOWBOB11 (Aug 31, 2017)

Excellent post g-man. Definitely going to be monitoring fungus outbreaks this year. Already had issues with leaf spot in parts of my lawn. I was going to leave it but it started to get worse so I sprayed propiconazole two days ago. It's already starting to look better. It's early for me to be seeing fungus but with all the rain this spring I shouldn't be surprised.


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## JDgreen18 (Jun 14, 2018)

SNOWBOB11 said:


> Excellent post g-man. Definitely going to be monitoring fungus outbreaks this year. Already had issues with leaf spot in parts of my lawn. I was going to leave it but it started to get worse so I sprayed propiconazole two days ago. It's already starting to look better. It's early for me to be seeing fungus but with all the rain this spring I shouldn't be surprised.


This year being my first year with my new lawn Im not taking any chances. I have all the products I need to apply a preventative fungicide until fall. I have granular and liquids with 3 different MOA. 
Last fall I got hit with leaf spot that carried over to this spring. It really hurt parts of my reno and took until just recently to bounce back from it.


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## g-man (Jun 15, 2017)

Bumping this.

It is likely that you have fungus if it is turning brown/yellow after all this rain and now heat. Most likely, it is leaf spot. Check the fungicide guide for what to use (eg. Azoxy).


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## Ldware9 (May 27, 2018)

Thank you for all the info and knowledge shared.


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## Green (Dec 24, 2017)

Around here, I'm starting to browning in lawns from a combination of drought stress/sun beating down and fungus. Anyone else seeing brownish lawns?


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## Jconnelly6b (Mar 4, 2018)

We had a bit showing over the weekend but the cool rains Monday made a big improvement. Lawns are looking good.


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## g-man (Jun 15, 2017)

I've seen multiple post around fungus issues. Most of the Midwest had a ton of rain, high humidity and temps between 75-80F.

Most of what I'm seeing is leaf spot. Azoxy is one of the best one for this in my opinion. Encouraging the grass to dry out will help. Once sun and dry heat shows up (if it does), it should go away. I've been doing preventive for it. Pushing for nitrogen causes more leaf spot problems. I like to collect my clippings to reduce the OM (dryer soil).

Dollar spot is another one active with the early morning dew/humidity. For higher hoc, this is mostly cosmetic. Nitrogen will push for grow so you can cut of the damage off. On low mow hoc, the damage is more noticeable and impactful since it has less leaf surface to recover. There are multiple strategies from golf courses. Removing dew (dew whips), rolling the lawn, increase foliar FAS, and fungicides. The model for DS helps to determine when you need protection.

The last one is brown patch. I've seen a few post, but not many. I think once temps go higher, we will see more of it. I would start a preventive on it.


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## g-man (Jun 15, 2017)

Summer heat is here. Indy had a few days above 80F and was very dry. Alaska had a 90F day. Once it gets this hot and the soil gets hot, the plants go into survival mode.

Key points:

- avoid pushing nitrogen. Yes I know the bag of milo says 04jul, but it is counterproductive to apply 0.75lb N/ksqft into a lawn when it is this hot. It is going to further stress the plant, thus requiring more irrigation. This in turn increases the chance of more fungus.

- ET is easy into the 0.20in a day. That means that in 2-3 days, the soil will need ~0.5in of rain/irrigation.

- Pythium Blight is starting to show up with all of the high dew point. This is an aggressive fungus, so be proactive.


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## FORT (Oct 26, 2018)

@g-man Thanks for updating this post, so much good information here!


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## FuzzeWuzze (Aug 25, 2017)

g-man said:


> Summer heat is here. Indy had a few days above 80F and was very dry. Alaska had a 90F day. Once it gets this hot and the soil gets hot, the plants go into survival mode.
> 
> Key points:
> 
> ...


What's considered heat for when to stop nitrogen? We're still in the 70's every day and usually overcast at least part of the day.

I noticed some fungal issues, i believe just do to my overwatering getting some overseed to take hold, dropped some Azoxy at curative rate a week ago and probably going to hit it with Propicanizole next weekend if weather permits.


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## g-man (Jun 15, 2017)

@FuzzeWuzze Ideal soil temp for cool season is 68F. The closer to it, the better it is to fertilize. Dr. Zac Reicher said in this article Fertilizing Home Lawns from UNL: avoid fertilizer above 80F. But I tend to avoid if the high temps are above 85F.


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## GoPre (Oct 28, 2017)

g-man said:


> - ET is easy into the 0.20in a day. That means that in 2-3 days, the soil will need ~0.5in of rain/irrigation.


This is something I don't quite have a grasp on. Would you mind pointing me somewhere to read up on it? I can't really find anything. Specifically, how you came to those numbers. (You already do so much, hope I'm not a bother)


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## g-man (Jun 15, 2017)

@GoPre I recently shared some links in this  thread. I plan on writing a more in depth report in the future (maybe winter at this point).

ET stands for  Evapotranspiration. The short of it is that water in the soil either is used by the plant, moves below the root level into the subsoil (eventually into aquifers, streams, rivers) or evaporates into the atmosphere. Multiple things affect it, like the soil type, the temperature, the solar uv energy, plant type, wind, etc. When I say 0.20in, it is taking all those factors into consideration and giving an estimate. Yesterday was cooler, so it was around 0.16in.


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## GoPre (Oct 28, 2017)

g-man said:


> @GoPre I recently shared some links in this  thread. I plan on writing a more in depth report in the future (maybe winter at this point).
> 
> ET stands for  Evapotranspiration. The short of it is that water in the soil either is used by the plant, moves below the root level into the subsoil (eventually into aquifers, streams, rivers) or evaporates into the atmosphere. Multiple things affect it, like the soil type, the temperature, the solar uv energy, plant type, wind, etc. When I say 0.20in, it is taking all those factors into consideration and giving an estimate. Yesterday was cooler, so it was around 0.16in.


Got it. I saved a copy of your Google sheet and use it every day. (Thank you) I have always kept an eye on the ET graph and columns, and had a rough idea of its purpose. Taking action and actually using the numbers is going to take a little education, yet.

Thanks again g-man.


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## Scagfreedom48z+ (Oct 6, 2018)

I was having the beginning stages or red thread, brown patch and leaf spot.

It wasn't a cheap app by any means but I hit my turf with:

Clearys 
Strobe 
Prop

Within a week and cut or 2, the lawn has rebounded and looks great. No sign of fungus. My plan was to knock out all possibilities of fungus that I had and it worked. I'm going to now stage it and apply 1 of those 3 options as directed after the 28 days of curative/preventative protection are up.


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## Suburban Jungle Life (Mar 1, 2018)

Scagfreedom48z+ said:


> I was having the beginning stages or red thread, brown patch and leaf spot.
> 
> It wasn't a cheap app by any means but I hit my turf with:
> 
> ...


Holy moly! Sweet mix!


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## Scagfreedom48z+ (Oct 6, 2018)

Suburban Jungle Life said:


> Scagfreedom48z+ said:
> 
> 
> > I was having the beginning stages or red thread, brown patch and leaf spot.
> ...


June and beginning of July are always when the fungus crushes my lawn. I did this to cure but also as a preemptive attack


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## g-man (Jun 15, 2017)

Let talk about the heat wave. Based on the numbers it is a high temperature but also high humidity. The humidity has my concern. The low temp tonight is going to be 80F. This is the perfect storm for fungus to grow at night.

Things I think you should not do:

- do not water 0.5in every day. That's just crazy. It is going to keep the soil saturated since at most the ET Is 0.30in daily. 0.5in every 2 days sounds better.

- don't water at night. A wet lawn all night is a bad idea.

- the high temp stress the lawn. Yes break the 1/3 guideline and avoid mowing. If you have to mow, do it late evening will help reduce stress

- do a walk-through in the am. Look for mycelium from fungus. Be quick to react.


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## Green (Dec 24, 2017)

g-man said:


> Let talk about the heat wave. Based on the numbers it is a high temperature but also high humidity. The humidity has my concern. The low temp tonight is going to be 80F. This is the perfect storm for fungus to grow at night.
> ...
> - don't water at night. A wet lawn all night is a bad idea.


Lol, my neighbor mowed this evening, and then watered at 9:30PM, wetting the first few feet of mine past the border, too. Thank goodness I sprayed Propiconazole on my new grass areas last week.



g-man said:


> - do not water 0.5in every day. That's just crazy. It is going to keep the soil saturated since at most the ET Is 0.30in daily. 0.5in every 2 days sounds better.


Totally agree. 0.5 inch every two days (e.g. Saturday, Monday), because ET is going to be 0.25 to 0.3 inches per day or so. I'm extremely lucky...I won't have to water most areas at all during the heat wave, because two nights ago I got over one inch rain.



g-man said:


> - the high temp stress the lawn. Yes break the 1/3 guideline and avoid mowing. If you have to mow, do it late evening will help reduce stress


Don't be like my neighbor, who mowed and watered tonight! I actually raised my HOC the other day, up by 0.25 inch (to 4" maximum) in the front, and up by 0.125 inch or so in the back. I left some areas unmowed totally this week because they don't grow. I won't be mowing again until early next week when it's cooler.



g-man said:


> - do a walk-through in the am. Look for mycelium from fungus. Be quick to react.


Good tip!


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## Budstl (Apr 19, 2017)

This has been the hottest stretch this summer. I haven't mowed since last sunday. It needs it, but I'll wait until temps break on monday. Only supposed to in the low 80s. Who else is going to get a break in temps? Anybody syringing?


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## Green (Dec 24, 2017)

Budstl said:


> Anybody syringing?


Nope, too much humidity so not needed (and possibly detrimental).

Only light watering if really needed due to heat stress.


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## g-man (Jun 15, 2017)

@pennstater2005 is your lawn fan running?


__ https://twitter.com/i/web/status/1152602439423369218


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## pennstater2005 (Jul 17, 2017)

g-man said:


> @pennstater2005 is your lawn fan running?
> 
> 
> __ https://twitter.com/i/web/status/1152602439423369218


I'm not an insane person so....no it's not :lol:

A 9 minute video on a fan blowing on the grass. Please tell me you didn't watch that.


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## Green (Dec 24, 2017)

We had wind today toward the PM. It also helped the guy who was hand watering and spraying.


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## social port (Jun 19, 2017)

Budstl said:


> Who else is going to get a break in temps?


mid 80s for a high are forecasted here for several days next week. I'll believe it when I feel it. Lows in the upper 60s are possible.
If it happens, I'm going to risk spot spraying with triclopyr. I have some wild violet that is driving me nuts.

I've been enjoying sporadic rainfall this week. Not great for disease, but it is still a relief from the heat.


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