Equation for determing watering duration?

[Stuttering Stan]

Does anyone have an equation that can determine the exact amount of water to apply on turf and shrub beds?

I have a new customer that I am trying to impress. $2 mil house with landscaping out the yang. I-20 on turf, 1800 sprays on beds. Right now the system is set to run rotars 3x/week for 15 min each and sprays 3x/week for 10 min each.
I am trying to figure out how to set the watering duration so each zone is getting the absolute correct amount of water.
For example, zone 3 (4 I-20's with 4 gal nozzles) output is 16 gal/min multiplied by 96.3 divided by 1050sq ft= 1.4 in/hr PR. How do I translate this into watering minutes per day/week?
I know the July ET for this area is 6.3 in/day.
Thanks for opening your book of knowledge to a piker like me

[FIMCO-MEISTER]

Does anyone have an equation that can determine the exact amount of water to apply on turf and shrub beds?

I have a new customer that I am trying to impress. $2 mil house with landscaping out the yang. I-20 on turf, 1800 sprays on beds. Right now the system is set to run rotars 3x/week for 15 min each and sprays 3x/week for 10 min each.
I am trying to figure out how to set the watering duration so each zone is getting the absolute correct amount of water.
For example, zone 3 (4 I-20's with 4 gal nozzles) output is 16 gal/min multiplied by 96.3 divided by 1050sq ft= 1.4 in/hr PR. How do I translate this into watering minutes per day/week?
I know the July ET for this area is 6.3 in/day.
Thanks for opening your book of knowledge to a piker like me

Did you get my PM? That VaTECH site has a calculator.

[Stuttering Stan]

Dang it, you're right. Went right over my head. I'll got here right now.

[irritation]

determine the exact amount of water to apply on turf and shrub beds?


I am trying to figure out how to set the watering duration so each zone is getting the absolute correct amount of water.


Never going to happen, irrigation is not an exact science and never will be.
There are way too many variables even on one small zone. Unless you are a full time caretaker of the landscape you will spend way too much time working on it.
Just use your best judgment and adjust accordingly throughout the season.

[Kiril]

I'll posted a nut load of information with regard to this, try searching for WUCOLS.

Second, ETo is NOT equal to actually ET, that is unless we are talking about the reference crop (usually cool season grass).

[Tony Clifton]

ET is 6.3" per day?

[Stuttering Stan]

ET is 6.3" per day?

My mistake- per month.
Kiril- thanks for the wucols site. I confused PET for ET.

[Armadillolawncare]

You would also need to know the specific plants and turf type and their indvidual watering requirements. For instance Bermuda grass and St. Augustine are both turf grasses but have different watering requirements, thus they would not need equal amounts of water.

[EagleLandscape]

You would also need to know the specific plants and turf type and their indvidual watering requirements. For instance Bermuda grass and St. Augustine are both turf grasses but have different watering requirements, thus they would not need equal amounts of water.

BS. They are not exact, but not far off. This junk about San Antonio banning St. Augustine is a crock. Water St. Augustine with the water requirement of Bermuda and it will look fine. Bermuda in residential lawns in Texas looks horrible.

[Armadillolawncare]

I am not sure about San Antonio banning St Augustine grass as I do not live or work there but I am sure that Bermuda grass is more drought tolerant then St Augustine and requires less water. There is a good article written by Richard L. Duble, Turfgrass Specialist that talks about differences in watering requirements for turf grasses. You can look under "Watering Schedules" about 3/4 of the way down the page for the drought tolerences of various turf grasses.
http://plantanswers.tamu.edu/turf/publications/water.html

You can also refer to table 3.6 & 3.7 "Drought Tolerences of Popular Turfgrasses" in the seventh edition text book of "Turfgrass Management" by A.J. Turgeon, Professor of Turfgrass Management at Penn State. These tables show Bermuda grass as having medium to high heat and drought tolerences while St. Augustine grass has low tolerences to both heat and drought. Translated this means Bermuda is more drought tolerant (requiring less water) then St. Augistine grass.

[hoskm01]

BS. They are not exact, but not far off.

Who said they were exact? He said they were different in fact.
Bermuda in residential lawns in Texas looks horrible.

Mayhaps with proper management...


http://www.lawnlogistics.com/Storage/frontgrass.jpg

[FIMCO-MEISTER]

The big problem with bermuda I think for maintenance guys who want primo lawns is that bermuda imo needs to be mowed every 3-5 days. Mowing it once a week it always looks scalped. The other issue is that every non-bermuda plant sticks out like a sore thumb. Especially nutsedge. When you have water restrictions is when bermuda really shines over St. Aug. You will lose a St. Aug lawn if you don't get water on it for a month in July but a bermuda lawn will bounce back. I'd still choose St. Aug over bermuda though.

[AI Inc]

Wheres the pin? Dont putting greens have pins?

[FIMCO-MEISTER]

Wheres the pin? Dont putting greens have pins?

That's the dog poop area.

[hoskm01]

That's the dog poop area.
Just think how ecent the actual green is!:)

[Kiril]

What a waste of water and other resources!

[hoskm01]

What a waste of water and other resources!
Go tell it on the mountain!

Ill have my 300 ft of lush if I want it!

[Kiril]

Go tell it on the mountain!

Heading there now. :laugh: