# Summer 2020



## g-man (Jun 15, 2017)

We are transitioning into summer (higher temps are showing up). While some of us had good rain quantity, that water is gone from the soil. @Pete1313 shared a view of this ET0 map and shared the link for the graph. In there you will also find a weekly ET0 rate.



As you can see, a lot of areas are in the 1.5in/week rate. For a cool season lawn, you multiple that by 0.80 (crop factor), so the lawn needs 1.2 inches of water/week. We are trending up, so that number will continue to climb. Water your lawn to keep up, more so if you continue to apply nitrogen. Try to water in 0.5-0.75in applications.

Check the map https://digital.weather.gov/mobile/index.php click on the cloud thunder and pick Total Weekly FRET


*Fungus*- This will be the main problem. Wet conditions with warm temps will promote fungus. 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* - In 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. 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 in high pH soils.

*Nitrogen* - Some of us love "throwing down" fertilizer. The nitrogen you applied (and worst with slow release sources), will continue to feed the lawn. This extra feeding means that the lawn will need extra water. I suggest controlling the impulse to continue to throw more nitrogen. Try to maintain a healthy grow with less being more sometimes.

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), knowing is important. It helps you discover problems before it is too late (not enough water or missing spots). Trying to keep a moisture level and avoid drought point (grass turns gray).

 Weeds - 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. Hand pulling might be better than a blanket spraying.

 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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## SNOWBOB11 (Aug 31, 2017)

Great post. I like the part about HOC bringing strong emotions


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## Babameca (Jul 29, 2019)

@g-man hat down for every informative post of yours!


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## 1028mountain (Oct 1, 2019)

@g-man where is the fungus guide??

Here it is: https://thelawnforum.com/viewtopic.php?f=9&t=4042


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## Stuofsci02 (Sep 9, 2018)

@g-man Excellent!


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## ScottieBones (Apr 2, 2020)

Nice post. Thx


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## Pete1313 (May 3, 2017)

Good stuff @g-man!


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## MasonDixon (Jun 2, 2020)

g-man said:


> [*]*Nitrogen* - Some of us love "throwing down" fertilizer. The nitrogen you applied (and worst with slow release sources), will continue to feed the lawn. This extra feeding means that the lawn will need extra water. I suggest controlling the impulse to continue to throw more nitrogen. Try to maintain a healthy grow with less being more sometimes.


How much water would you suggest for a late-spring application of nitrogen such as urea? How much per week or day, and for how many weeks or months should that watering schedule continue? Thanks


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## g-man (Jun 15, 2017)

@MasonDixon too many variables to even guess. Use the ET0 at 100 crop factor for a month, but use your eyes. If the lawn looks like it needs water, irrigate.


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## MasonDixon (Jun 2, 2020)

g-man said:


> @MasonDixon too many variables to even guess. Use the ET0 at 100 crop factor for a month, but use your eyes. If the lawn looks like it needs water, irrigate.


Thank you


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## g-man (Jun 15, 2017)

It is very dry here in Indy. Double check your irrigation. I had a dry spot because the nozzle was not setup right (bottom of the picture).


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## Zcape35 (Sep 17, 2019)

Thanks for the timely post!!!


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## gmorf33 (Jul 30, 2019)

That explains why i've had to water so much this week to get the lawn green again after getting a little behind using the "wait for initial signs of needling before watering" method. 1.83 * .8 crop factor = 1.46". Been running three 10 minute soaks with about 40m between soaks to prevent run off (and because my control box is old and can only trigger on the hour), every 2 days. That puts me at about .55" each day over a ~3 hr period for a total of 1.9" of water for the week, which is just a tad over the FRET, which makes sense as i needed a little catch-up. I'll be using this map for the rest of my summer to help gauge when/if i should bump my daily watering total to a 4th soak. With Kansas summer's i doubt i'll be seeing it go down any time before Sept.

Cool post! Thanks!!


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## Ohio Lawn (Mar 20, 2019)

I've been wondering why my lawn is showing signs of drought stress. This makes sense. It seemed to rain a ton in May and then completely shut off in June.

Does anyone have info or a link that explains Et0 in simple terms for a less than intelligent guy like myself?


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## g-man (Jun 15, 2017)

Fyi, I uploaded an ET and Irrigation Guide . Since it applies to cool season and warm season lawns, I placed it in the Irrigation folder. Summer is here, so get your irrigation approach figured out.


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## g-man (Jun 15, 2017)

3 words:

Hot, Hot, Hot









-https://www.cpc.ncep.noaa.gov/products/forecasts/

Forecast is showing above average heat. By careful with too much nitrogen or even pgr.


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## Pete1313 (May 3, 2017)

@g-man look at that, the worst part of that map is going right thru our neck of the woods. Bring it on!!


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## SumBeach35 (Jul 11, 2019)

I checked soil moisture last evening after 3 days of no water. Ill definitely be maintaining my watering schedule and adding late afternoon syringing to the south facing front yard on the hottest days.


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## behemyth (Jun 8, 2019)

Here's my front yard, I also live in the Indy area... I do have an in ground irrigation system. The yellow spots are thin areas i have because multiple ISP's ripped up parts of my yard to bury cable, and I haven't dropped more seed. That's happening this fall.


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## SumBeach35 (Jul 11, 2019)

Nice infographic to show just how little rain we got in June for Rochester NY.


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## g-man (Jun 15, 2017)

Fungus is here. Some of us are having a high heat and high humidity weather. I've been getting daily pop thunderstorms at 3pm. That's the worst timing to get a the grass wet and then get sun/heat again.

The two main fungus to be concern are: brown patch and pythium blight.

I've been monitoring my yard and wanted to treat it 2 days ago, but the pop storms screw my plans. My front got hit with BP, but I dont know when the storms will let me treat it.


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## Justin9314 (Jan 22, 2020)

Major heat coming with little support of rain. Sounds like our only hope this year might be tropical related. I actually ran across this today and found it pretty interesting. Just wish their services weren't so expensive.

https://www.youtube.com/watch?v=QgyijhJNjEw&feature=youtu.be&fbclid=IwAR0BRVWEuqcOanyOQan2_SyysREZiBgudX2Dp2Lmsrb94UYCI5jBeSIBFEY


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## g-man (Jun 15, 2017)

Fungus continues to be a concern. We had some high temps that stressed a lot of lawns. Some leaf blades will suffer and die. It is normal. If you dont have irrigation you will have more. But a lot of us are getting a ton of rain (I'm at 2.3in this week). Dew Point is also high (72F for me). This means that the lawn will be wet and stay wet. The dead material from the summer heat, moisture and heat = petri dish.

Keep an eye for PB and BP. Have a fungicide ready to apply.


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## Old Hickory (Aug 19, 2019)

g-man said:


> Keep an eye for PB and BP. Have a fungicide ready to apply.


What if we're on a preventative program per the fungicide guide? If we see any of those can we hit it with spot spraying?


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## bernstem (Jan 16, 2018)

In St Louis here, it is raining every 1-2 days. Great for saving water, but with the heat disease is a concern. The only good news is that the end of the heat is in sight.


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## g-man (Jun 15, 2017)

@Old Hickory I'm not a huge fan of spot spraying for fungus. I can't explain it. I just think that if there is fungus breaking thru in an area, it can break thru in others. If you are in preventive and get a fungus, check that the fungicide covers it, and apply a fungicide to get you to curative rates.

The end of the heat is near. Soon we will complain of too much grow and having to mow. Then we will complain of the white stuff.


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## M32075 (May 9, 2019)

Long island NY here. Drought and unbelievable heat day after day week after week is a struggle for me. Watering every other day with high humidity is a fungus struggle that is somewhat under control but it's still only middle of July I'm thinking I better order some seed for September.


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## jingobah (May 6, 2019)

Long Island here also, the heat is just cooking the lawn, grass that was green one day ago is now turning brown in spots all over, had fungus issues all throughout the summer so far...just put down some propi and trying not to over water even though it's so hot, sprayed some Hydretain again tonight, looks like I'll be reseeding some spots again like I always have to come September...


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