Greenhouse Irrigation System Calculator

Size a drip or overhead irrigation system for greenhouse benches including emitter count, flow rate, and water usage.

Inputs

Number of Benches

Bench Length

Irrigation Type

Emitter Spacing

Emitter Flow Rate

GPH

Waterings per Day

Minutes per Watering

min

Tab to move between fields

Results

Total Emitters

540

Daily Water Usage

90 gal

≈ 4 wheelbarrows

Emitters per Bench90

System Flow Rate4.5 GPM

Gallons per Watering45 gal

Monthly Water Usage2,700 gal

Tubing Needed540 ft

How to Use This Calculator

Enter the number of benches and bench length in feet, then select drip irrigation (for containers) or overhead sprinkler (for flats and plugs).
Enter emitter spacing in inches and flow rate in GPH per emitter, plus waterings per day and minutes per watering cycle.
Review Total Emitters, System Flow Rate (GPM), and Gallons per Watering to size your supply line and header pipe.
Note Daily Water Usage (gal) and Monthly Water Usage (gal) to budget water costs and verify your water supply capacity.
Use Tubing Needed (ft) to calculate your material order for the main and lateral distribution lines.

How the result changes with Bench Length

Bench Length	Total Emitters	Daily Water Usage
24	144	24 gal
73	438	73 gal
131	786	131 gal
180	1,080	180 gal

What each input means

Number of Benches: Total benches to irrigate.
Bench Length: Length of each bench.
Irrigation Type: Drip for containers, overhead for flats and plugs.
Emitter Spacing: Distance between drip emitters or nozzles.
Emitter Flow Rate: Gallons per hour per emitter.
Waterings per Day: Number of irrigation cycles daily.
Minutes per Watering: Duration of each irrigation event.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Number of Benches = 6, Bench Length = 90, Irrigation Type = 1, Emitter Spacing = 12 = 7 input(s) provided
Calculate Total Emitters
Total Emitters
540 = 540
Calculate Daily Water Usage
Daily Water Usage
90 = 90
Calculate Emitters per Bench
Emitters per Bench
90 = 90
Calculate System Flow Rate
System Flow Rate
4.5 = 4.5

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