# How often to irrigate?



## ahartzell (May 18, 2017)

This is a big/controversial question (I'm surprised it hasn't been asked on here before...unless I missed it).

How often do you irrigate? I've heard/read anything from daily to very infrequently (with all the philosophies of why).


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## Spammage (Apr 30, 2017)

When the grass starts to show drought stress and then I water deeply over 3 cycles of the system.


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## Mightyquinn (Jan 31, 2017)

I usually have to water every 2-3 days in heat of the Summer. I usually try to water no more than a 1/2" at a time as my soil will not hold water for much longer than that. It's just something you will have to play by ear. The longer you can go between waterings the better as it makes your grass grow deep roots looking for water.

This year I am trying to get my Rachio set up so that it will do all the thinking and I can just sit back and relax. I'm also going to reevaluate my irrigation nozzles and adjust them accordingly.


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## GrassDaddy (Mar 21, 2017)

The reason there is so much arguing.. everyone has different soil and weather. My soil is very healthy so I can do one inch once a week but with the reno I may goto twice a week in mid summer.

Now if you have sandy soil the water will leave the soil faster. if its hotter in your area it will evaporate faster.

the key is to start with the recommendation and modify from there if you see the lawn showing stress.


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## j4c11 (Apr 30, 2017)

My take on watering:

You wait until there's signs of drought stress. When there's signs of drought stress, you water until you can easily push a 6" screwdriver into the soil all the way to the handle. Rinse, repeat.

The method above has the following advantages:
- It is not dependent on weather. In 95 degree weather you get drought stress in 4-5 days, in 80 degree weather in 10 days. If it rains, it automatically resets. 
- It is not dependent on soil type. If a soil retains more water, the grass will last longer before it shows drought stress. Also, you're not watering in inches, you're watering to saturate the root zone. It could take an inch of water for some soils, half an inch of water for others. 
- It allows you to go the longest on the least amount of water, so it promotes root growth while saving money on water.


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## GrassDaddy (Mar 21, 2017)

Yeah that's a good way to put it. We have water restrictions so there are only 2 times per week I can water, so I get fixated on 1 or 2 times a week method. The irony is I'd use less water if there weren't restrictions.. Sometimes I water even if it's forcast to rain because well it might not rain, and I can't chance having to wait 3 more days if it doesn't..


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## j4c11 (Apr 30, 2017)

That's another important thing that needs to be mentioned. When you're waiting until drought stress sets in, your margin of error is thin. Unless you know for sure it's going to rain in sufficient amounts, irrigate. I've been burned many times by rain in the forecast that never comes, or comes but passes my house by a mile or two, or comes and only drops a tenth of an inch.


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## dfw_pilot (Jan 28, 2017)

A Rachio is a good option for those of us not home every day to check on the grass. Now that I think about it, it's a good option for a lot of reasons.


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## MrMeaner (Feb 21, 2017)

We only average 18" per year of rainfall here in Lubbock. I personally water from a water well and only water just enough to keep the grass nice and green. I have such a large yard with 16 zones and I am using Hunter PGP heads.

I took inventory and mapped out each zones of my irrigation system... when the installer left every single head in the lawn had 1 gpm nozzle.... well some heads were 90 degree heads, some were 120-180 degree heads and some were full 360 heads. Working within my Gallons Per minute and pressures from my water wells, I switched out nozzles on heads that sprayed more the 90 degrees. I have 2-2.5GPM nozzles in the 120-180 degree heads and 4 gallon nozzles in the 360 heads.

Once that was completed, I did the tuna can tests and based on Hunters nozzle precipitation charts I came up with estimated watering times for each station. With the Hunter controller I have you can seasonally adjust higher or lower zone watering times.... I have some zones which run for as little as 15mins in the spring and fall, twice a week. I also have other zones with run up to 1 hr , twice a week in the spring and fall. During the heat of summer those run times can vary up to 30-45mins to 1.5 -2.00hrs per zone twice a week.

I water at night when the wind is usually blowing the least, and can start the front yard at 12:00 midnight and it still be running when I wake up in the morning depending on time of year. I water the back the next night, the front the following night and the back again the following night. So I water the Front on Mondays and Wednesday and the back Tuesday and Thursday. The flower beds and tree drip Irrigation is run 2-3 times per week when I am not running irrigation for the lawn.


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## dfw_pilot (Jan 28, 2017)

Mr. Meaner brings up a great point about Season Adjust. Back when I had my manual Hunter, the seasonal adjust feature was, in my opinion, _the best part of the hunter controller_.

Use the tuna can method or some of these short rain gauges to find out how long each zone in your system needs to run to get one inch.

Set the seasonal adjust to 100% and then set each zone's run time to the amount of time needed to get one inch of water, i.e. Front Yard: 0:45 minutes, Back Yard: 0:55 minutes, Side Yard: 0:24 minutes, etc.

In the heat of summer, most lawns need ~ 1 inch per week. If you get 1/4" of rain, you simply set the seasonal adjust to 75%; if you get 1/2" of rain, set your season adjust to 50%. Dead easy. Also, each 10% is then 1/10" of water. Simple. It makes keeping track of run times and water usage much easier. _So, don't overlook the power of the seasonal adjust._


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## Ware (Jan 28, 2017)

dfw_pilot said:


> ...In the heat of summer, most lawns need ~ 1 inch per week. If you get 1/4" of rain, you simply set the seasonal adjust to 75%; if you get 1/2" of rain, set your season adjust to 50%. Dead easy. Also, each 10% is then 1/10" of water. Simple. It makes keeping track of run times and water usage much easier. _So, don't overlook the power of the seasonal adjust._


I like it. :thumbup:


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## Ware (Jan 28, 2017)

GrassDaddy said:


> Yeah that's a good way to put it. We have water restrictions so there are only 2 times per week I can water, so I get fixated on 1 or 2 times a week method. The irony is I'd use less water if there weren't restrictions.. Sometimes I water even if it's forcast to rain because well it might not rain, and I can't chance having to wait 3 more days if it doesn't..


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## MrMeaner (Feb 21, 2017)

dfw_pilot said:


> Mr. Meaner brings up a great point about Season Adjust. Back when I had my manual Hunter, the seasonal adjust feature was, in my opinion, _the best part of the hunter controller_.
> 
> Use the tuna can method or some of these short rain gauges to find out how long each zone in your system needs to run to get one inch.
> 
> ...


Keep in mind different heads have totally different precipitation rates.. You really need to do an irrigation system audit of each zone to know how much your irrigation system is really putting out over a given about of time. Rotors typically take must longer other types of heads. I know here in my city, with little yearly rainfall, high winds and evapo - transpiration rates I have to water more than 1" per week on certain zones out in the middle of the yard that gets no shade and full sun. I usually just check to see if the grass is stuggling any and crank up the seasonal adjust some, I know I mine I can go over 100% to like maybe 150% of standard time.. and would assume most contollers would do the same.


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## J_nick (Jan 28, 2017)

During the heat of summer with no rain I start getting localized dry spots around day 4 so I then water with .6" of irrigation.


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## dfw_pilot (Jan 28, 2017)

MrMeaner said:


> Keep in mind different heads have totally different precipitation rates.


Precisely. That's why each zone must be audited to find out how long it will take to get an inch (or whatever depth you like). Rotor zoned run much longer than sprays, usually.


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## GrassDaddy (Mar 21, 2017)

Ware said:


>


Pretty much. Unless you are a business on the *main road* through town, then you can water twice per day for over an hour at a time...



dfw_pilot said:


> ...In the heat of summer, most lawns need ~ 1 inch per week. If you get 1/4" of rain, you simply set the seasonal adjust to 75%; if you get 1/2" of rain, set your season adjust to 50%. Dead easy. Also, each 10% is then 1/10" of water. Simple. It makes keeping track of run times and water usage much easier. _So, don't overlook the power of the seasonal adjust._


Doh!! I forgot about that feature. I had been adjusting the times to each zone lol


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## ahartzell (May 18, 2017)

Didn't feel like making new thread or derailing someone else's...but for those of you who have irrigation systems: what kind of heads/nozzles do you have and how long are you typically running a zone? I've seen people on here saying they're running irrigation for a long time (or so it seems to me).

The other day, I threw one of my wife's measuring cups (which is about an inch deep) into the very center of the yard. The main lawn is it's own zone and is covered by 6 rotating nozzles. After 10min, it was only a third full. That means I should run that zone for 30min...which seem like a LONG time to run a zone.

Also, some people on here were talking about measuring each head and calibrating each one to put out the same amount of water. I'm definitely new to this, but I don't think I can turn on one head at a time to measure how much it's putting out. One zone sure, but then I can only measure what the zone is doing...


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## g-man (Jun 15, 2017)

You calibrate the zones. You design the outputs of the heads using nozzles that output a set gpm. The idea is to balance a zone so that zone gets the same rate of irrigation. That's what folks described. It would be hard to measure each head and the info is provided by the vendor for each nozzle type.

I use Hunter mp nozzles. If designed correctly, they output a rate of 0.4in/hr. It takes 2.5hrs per zone to get an inch. So running your zone 30min is not long at all.

Don't use just one cup in a zone. Place at least 5 (center and near the corners). You want to see if the zone is balanced. Tuna cans work pretty good or anything with straight walls.


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## ahartzell (May 18, 2017)

g-man said:


> You calibrate the zones. You design the outputs of the heads using nozzles that output a set gpm. The idea is to balance a zone so that zone gets the same rate of irrigation. That's what folks described. It would be hard to measure each head and the info is provided by the vendor for each nozzle type.
> 
> I use Hunter mp nozzles. If designed correctly, they output a rate of 0.4in/hr. It takes 2.5hrs per zone to get an inch. So running your zone 30min is not long at all.
> 
> Don't use just one cup in a zone. Place at least 5 (center and near the corners). You want to see if the zone is balanced. Tuna cans work pretty good or anything with straight walls.


If my nozzles are the same, then last year I was watering at like 0.1in 3x week 😳

And yet lawn looked...ok lol


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## g-man (Jun 15, 2017)

The lawn might look ok, but you are encouraging shallow roots, which means watering more often. Calibrate your system and give it a try.


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## ahartzell (May 18, 2017)

g-man said:


> The lawn might look ok, but you are encouraging shallow roots, which means watering more often. Calibrate your system and give it a try.


That's on the agenda for today or tomorrow 😜


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## southernguy311 (Mar 17, 2017)

ahartzell said:


> g-man said:
> 
> 
> > You calibrate the zones. You design the outputs of the heads using nozzles that output a set gpm. The idea is to balance a zone so that zone gets the same rate of irrigation. That's what folks described. It would be hard to measure each head and the info is provided by the vendor for each nozzle type.
> ...


That may have worked fine before, but you are venturing into reel mower territory and the margins are finer as the grass gets shorter.


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## ahartzell (May 18, 2017)

Is there any reason to irrigate extra mid-day in heat of summer (110 deg) or just stick to ~1" weekly? Think I've seen some irrigate mid-day to cool canopy but idk if it's worth it with Bermuda.


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## Ware (Jan 28, 2017)

ahartzell said:


> Is there any reason to irrigate extra mid-day in heat of summer (110 deg) or just stick to ~1" weekly? Think I've seen some irrigate mid-day to cool canopy but idk if it's worth it with Bermuda.


I have never irrigated mid-day to cool the canopy. Back when I was using hose-end sprinklers, I did water some mid-day, but that was merely out of necessity.


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## ahartzell (May 18, 2017)

Ware said:


> ahartzell said:
> 
> 
> > Is there any reason to irrigate extra mid-day in heat of summer (110 deg) or just stick to ~1" weekly? Think I've seen some irrigate mid-day to cool canopy but idk if it's worth it with Bermuda.
> ...


Yea the ones I've seen doing it didn't have irrigation systems. I guess it was out of necessity to get enough water per week or whatever. I didn't think so but for some reason when it's blazing hot outside I have an urge to give the lawn a drink lol


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## Mightyquinn (Jan 31, 2017)

ahartzell said:


> Ware said:
> 
> 
> > ahartzell said:
> ...


When the temps start getting in the 95+ degree range, I always start giving the lawn a little extra water as the 1" per week is just a guideline.


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## J_nick (Jan 28, 2017)

+1 MQ, when it starts getting hot like it is now I normally water .6" every 4 days or so. With a full inch I need water within 4 days and with .6" it needs water in 4 days. I think that's just the holding capacity of my sandy soil.

Although they might be localized dry spots. The whole yard never looks wilted only a few spots but with the irrigation being on a well, water is relatively cheap so the whole lawn gets water.


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## g-man (Jun 15, 2017)

ahartzell said:


> Is there any reason to irrigate extra mid-day in heat of summer (110 deg) or just stick to ~1" weekly? Think I've seen some irrigate mid-day to cool canopy but idk if it's worth it with Bermuda.


This one:

http://thelawnforum.com/viewtopic.php?f=5&t=594


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## ahartzell (May 18, 2017)

Yea I was considering doing like 0.75" every 4-5 days (so more than 1" per week) bc it's so dang hot


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