once I"m do the efforts to figure out exactly how much to water things in my garden I"ll often see things like, "...they will need 1-2 inches of water every week."

From what i understand, this is the very same as if there had actually been 1-2 inches of rain. My trouble is that everything for drip irrigation systems it seems to be ~ to measure in gallons or liters per hour.

How can I go about converting inches to gallons?


One us gallon is 231 cubic inches.

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One square yard is 1296 square inches.

So "1 customs of rain" is 1296/231 or about 5 and a half US gallons or 21 liters of water every square yard.

The flow rate with your drip device obviously depends on the area it is watering and also how plenty of hours the is on each day, yet that offers you a beginning point.

Note: 1 imperial (UK) gallon is 277 cubic inches which provides 4 and three 4 minutes 1 UK gallons per square garden - however commercial UK irrigation systems will certainly be stated in metric systems so the is relatively irrelevant.

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edited Jul 22 "19 at 9:17
reply Jul 22 "19 in ~ 9:09

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I simply went v the exact same thing myself when setting up mine drip watering system. It"s in reality pretty easy.

The formula is as follows:

Pr = 96.25 x full GPM of every emitters (gal/min) ------------------------------------------- full area (ft²)Where Pr is the "precipitation" rate in inches/hour.

To make it more clear, I"ll take an example from my own garden. I have actually 6 slicing tomato tree planted in around an 18" x 3" area. I have actually 2 part of drip tubing the stretch on either next of the tree which carry out a total of 29 0.9 gal/hour (GPH) emitters within the area. I likewise have an additional single 1 GPH emitter for each plant.

So, to find the total GPM of every emitters (gal/min) I do the following:

29 x 0.9 gal/hr = 26.1 gal/hr

6 x 1.0 gal/hr = 6 gal/hr

26.1 gal/hr + 6 gal/hr = 32.1 gal/hr

To get gal/min, division by 60:

32.1 gal/hr / 60 = 0.535 gal/min

So, plug that into the equation and also you get

Pr = 96.25 x 0.535 gal/min --------------------- 18 x 3So, Pr = 51.5 / 54 or .954 inches/hour

Let"s say I desire to provide them 2 inches of water per week. At 0.954 in/hr, I"d must water a total of 2.097 hours, or 126 minutes every week.

I contrasted this calculated method to an really physical check (held bath tub underneath 2 that the drip ice cream emitters for 30 minutes), and also it"s pretty much dead on.

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I highly recommend setup this up together a spreadsheet through columns because that width and length, and also then columns because that the amounts of each speed emitter girlfriend have.