# Watering in high heat for Tall Fescue



## Mireland (Jul 19, 2020)

Hi,
I have a tall fescue grass and really struggled last year around this time with keeping my lawn hydrated. I live in VA and its been hitting 90s consistently with no rain in sight. We are officially in a drought according to my lawn people. So with that said I know that you should only be watering 3-4x a week getting 1/2in per watering session. When I did that my lawn saw severe stress, I was able to get it back by water 4 days straight. Lawn Doctor says not to do that as it will cause my roots to sit close to the surface..... wanting to hear what everyone else does. In this severe heat do you still get away with only watering 3x a week or once it gets to 90s you should be watering every day?


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## Powhatan (Dec 15, 2017)

For those that irrigate, the popular recommendation is to water deeply and infrequently, targeting 1" per week either on one day or 0.5" on two separate days early in the morning before the day's heat sets in.

As for me, I don't irrigate the whole yard, sometimes I'll water a targeted area for a specific purpose.


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## tjcarpenter1 (Apr 17, 2020)

Powhatan said:


> For those that irrigate, the popular recommendation is to water deeply and infrequently, targeting 1" per week either on one day or 0.5" on two separate days early in the morning before the day's heat sets in.
> 
> As for me, I don't irrigate the whole yard, sometimes I'll water a targeted area for a specific purpose.


When you say you don't water, are you basically letting the lawn go dormant? How does that work on keeping the grass alive? I am considering something along these lines, as I don't have irrigation currently.


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## situman (Nov 3, 2020)

1 inch of water generally doesnt work unless there's rainfall. Irrigation is a supplement to rainfall. Irrigation is the life support. Rain is the cure.


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## Powhatan (Dec 15, 2017)

tjcarpenter1 said:


> Powhatan said:
> 
> 
> > For those that irrigate, the popular recommendation is to water deeply and infrequently, targeting 1" per week either on one day or 0.5" on two separate days early in the morning before the day's heat sets in.
> ...


I don't have the water resources to sprinkle thousands gallons of drinking water on the lawn every week so I do other things in trying to promote grass health that can be reasonably heat & drought tolerant that are in the lines of good cultural practices, organics, healthy soil, biodiversity. I'm basically maintaining the grass to search for water the natural way - further down in the soil using deeper roots. In July there are areas in the lawn that go brown due to heat/drought and with rains a few weeks later the grass normally comes back green. Sure some % dies off and I have to overseed.


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## Lawn Whisperer (Feb 15, 2021)

I'm also in the mid Atlantic and the weather has been very dry this spring. I parched parts of my lawn trying to water 1" a week. My mistakes were that I tried watering 1" over the same period, not using the soak and cycle method. Second, mistake is that when I started watering my lawn, it was probably less than 50% saturated, maybe even close to 0%. My third problem is that I'm still trying to fix compaction and debris issues on my lawn.

I recommend getting your soil saturation back to 100%, water your lawn to an inch using the soak and cycle method (or wait for a good amount of rain), then go back to watering 1/2" for 2-3 times a week, using the soak and cycle method. Different soils have different water absorption rates, some soils can only absorb .2" of water an hour.

I had to read over g-mans  ET and Irrigation Guide .

How long does it take you to water .2 acre?


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## BH Green (Apr 9, 2020)

@Mireland,
Lawn Whisperer has some good points above, and I also recommend reading g-man's ET and Irrigation guide-you can figure out how much moisture your root zone holds, and roughly how fast that water gets depleted. The idea is to water deeply to saturate the root zone, then allow the top 50% to dry up before watering again. You probably need to be watering more than 1/2 inch to saturate your root zone which would allow you to space irrigation a little more.

You can also use a soil probe to check on moisture levels. Lately I've been going out the night before I run an irrigation cycle to grab a couple cores to see how deep the moisture is. If it looks bone dry down to six inches you know to run at least 1" of water. If only the top 3-4 inches of soil are dry, I can get away with less irrigation the next morning. The amount of water you need will change on a daily and weekly basis based on conditions.


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## Fraust (Apr 4, 2021)

Lawn Whisperer said:


> I recommend getting your soil saturation back to 100%, water your lawn to an inch using the soak and cycle method (or wait for a good amount of rain), then go back to watering 1/2" for 2-3 times a week, using the soak and cycle method. Different soils have different water absorption rates, some soils can only absorb .2" of water an hour.


Piggybacking off this, how do you account for the rate of rainfall into ET calculations? For instance, my soil is a pretty heavy clay and even when I'm only irrigating 0.5" I break it up into 2 cycles (watering 1 zone to about 0.25", then hitting another zone before returning to the first again) to avoid runoff and pooling. Earlier today, the rain gauge says we got nearly 2.5" of rain, but it all came down in less than 3 hours. So, do I count it as likely being back to 100%? Am I overthinking this whole thing?


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## Lawn Whisperer (Feb 15, 2021)

Fraust said:


> ... Earlier today, the rain gauge says we got nearly 2.5" of rain, but it all came down in less than 3 hours. So, do I count it as likely being back to 100%? Am I overthinking this whole thing?


It depends on how much water your soil can absorb. If your soil is mostly clay for example, it can only absorb .2" an hour, then your soil will absorb about .6" in three hours and remainder of the water will drain off, if it's on any type of slope. These are just estimates, as recommended as recommended by BHGreen, soil probe is the best way to determine soil saturation.

Here's a K-State article I've read lately.
https://www.johnson.k-state.edu/lawn-garden/agent-articles/lawns/watering-the-lawn.html


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## Lawndress (Jul 9, 2020)

Given how well my lawn absorbs water, it doesn't get sad for a good week after a big rain. So I don't really care how fast it falls.


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## g-man (Jun 15, 2017)

Powhatan said:


> tjcarpenter1 said:
> 
> 
> > Powhatan said:
> ...


I like powhatan approach and to add to this. If you had a large area to maintain, watering can get really expensive. But just manage your expectations. Think of the HOA common areas or the highway exits. Most are never irrigated. They get a prem (maybe) and some fert and rain. They definitely don't get overseed ever. The grass survives the summer and does just fine from a distance. Is it perfect? Nope. As long as the grass gets around 1in every 3 weeks, it will survive a dormant period. Maybe do an area of the front lawn and close to the house that is irrigated.


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## Lawndress (Jul 9, 2020)

Powhatan said:


> tjcarpenter1 said:
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> > Powhatan said:
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I'm on well and also there are zero people I'm affecting negatively by watering as much as I please. I can all but spit into the ocean where I am, so the groundwater is just about to go out to sea. Not everyone has a dearth of water!

But I obviously don't care to water my septic field all that much. So I am much lower water input in the backyard. I stay under 1" per week when it's not rainy.


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## Delmarva Keith (May 12, 2018)

Powhatan said:


> tjcarpenter1 said:
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> > Powhatan said:
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I think you are a wise man. Right plant / right place. Plants need supplemental water to get established without high mortality rates. After that, if a plant can't get by on its own, maybe it just doesn't belong there. I have these thoughts more often lately (usually after many hours working outside in uncomfortable heat lol).


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## Jackson (Sep 18, 2019)

What's your height of cut?


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## Powhatan (Dec 15, 2017)

Jackson said:


> What's your height of cut?


OP or me?

Mine is currently 3.25".


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## spaceman_spiff (Feb 5, 2021)

Fraust said:


> Piggybacking off this, how do you account for the rate of rainfall into ET calculations? For instance, my soil is a pretty heavy clay and even when I'm only irrigating 0.5" I break it up into 2 cycles (watering 1 zone to about 0.25", then hitting another zone before returning to the first again) to avoid runoff and pooling. Earlier today, the rain gauge says we got nearly 2.5" of rain, but it all came down in less than 3 hours. So, do I count it as likely being back to 100%? Am I overthinking this whole thing?


You should consider a Rachio 3 irrigation controller. It literally does all of these calculations for you behind the scenes. Uses forecasts to estimate ET, cycle and soaks based on soil and sprinkler nozzle type and precipitation rate, skips based on X" of predicted/actual rainfall, wind skip over X mph, adjusts irrigation lengths based on season/weather, etc. It's a really fantastic controller and lets you min/max your irrigation as much or as little as you want. I find having all these knobs make me mess with it even more now


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## Fraust (Apr 4, 2021)

spaceman_spiff said:


> Fraust said:
> 
> 
> > Piggybacking off this, how do you account for the rate of rainfall into ET calculations? For instance, my soil is a pretty heavy clay and even when I'm only irrigating 0.5" I break it up into 2 cycles (watering 1 zone to about 0.25", then hitting another zone before returning to the first again) to avoid runoff and pooling. Earlier today, the rain gauge says we got nearly 2.5" of rain, but it all came down in less than 3 hours. So, do I count it as likely being back to 100%? Am I overthinking this whole thing?
> ...


I don't have in-ground irrigation. I run two 2-spigot Orbit programmable timers, with 4 hoses and basic oscillating sprinklers. Definitely not ideal, but does the job for now. Slowly trying to convince my wife to let me install irrigation. All that control sounds great though. Some day 🤞


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## Jackson (Sep 18, 2019)

Powhatan said:


> Jackson said:
> 
> 
> > What's your height of cut?
> ...


3.25 is alright for now, but if you are not going to irrigate you need to get it around or over 4" in the heat of summer. Pete from GCI on YouTube 'HAD' a tall fescue lawn in the Carolinas without irrigation that looked amazing throughout the summer because of cultural practices.

You have to let it get long to shade the soil and collect atmospheric moisture, you have to be willing to not mow and let it get shaggy when its hot and dry to reduce stress, and you have to properly fertilize so that your lawn has the nutrients to handle the heat.


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## Virginiagal (Apr 24, 2017)

Jackson, Powhatan is not having problems with his grass even though he irrigates only targeted areas. It's Mireland who is concerned about watering. You are recommending 4" for height of cut. I have done that in the past and think it doesn't allow enough air flow and the blades don't dry out fast enough. Damp blades in warm, humid conditions lead to fungus like brown patch. I'm doing 2.5 inches and am happy with that. I may raise it to 3 inches in July. Mireland, I suggest watering in the early morning when you do water so the grass blades will dry out. Watering in the afternoon or evening prolongs the dampness through the night. Don't fertilize now, wait until early fall. Use a preventative fungicide program. Brown patch can cause considerable loss.


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## Virginiagal (Apr 24, 2017)

Jackson, Powhatan is not having problems with his grass even though he irrigates only targeted areas. It's Mireland who is concerned about watering. You are recommending 4" for height of cut. I have done that in the past and think it doesn't allow enough air flow and the blades don't dry out fast enough. Damp blades in warm, humid conditions lead to fungus like brown patch. I'm doing 2.5 inches and am happy with that. I may raise it to 3 inches in July. Mireland, I suggest watering in the early morning when you do water so the grass blades will dry out. Watering in the afternoon or evening prolongs the dampness through the night. Don't fertilize now, wait until early fall. Use a preventative fungicide program. Brown patch can cause considerable loss.


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## Lawndress (Jul 9, 2020)

Powhatan said:


> Jackson said:
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> 
> > What's your height of cut?
> ...


My lawn tractor cuts at 2.25" when it's set at 3. Very annoying. I would like to cut as high as possible.


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## LawnSolo (Jul 17, 2018)

There is a little trick I learned last year from Pete from GCI on YouTube.

And it seemed to have worked very well.

He explained that when irrigating in the heat of the summer, we should run the zones twice. In my situation it will take about 32 minutes to get .5" of water per zone. So instead of running 32 minutes per zone, I'm running each zone for 16 minutes then run it again after all the zones cycle is completed.

The explanation is that if you run the zones when it's hot and dry then you will be wasting runoff water. By splitting the irrigation in 2 per each zone, you are allowing the soil to soften with the first pass and absorb more when the second pass comes in place.

I'm doing this ever since and it's day and night difference. I even do this when watering my vegetables garden


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