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Thursday, December 17, 2015


This article was designed to introduce you to spray systems, and contains some of the information you will need to get started.

(For more advanced instructions on how to design and install an underground irrigation system CLICK HERE)

The reason you would use a spray system over a direct watering system, is the required watering area is bigger than or too densely planted to make it economical. With a spray system you can cover a larger area with fewer heads. Whether you go to a spray or direct watering system you can connect them to your automatic sprinkler system.


  1. Draw a plan of your landscape.
  2. Determine the area's that are to be sprayed.
  3. Determine the style or styles of watering you will use.
  4. Determine the amount of time per week you will have the system on.
Step 1

Draw a plan of your area to be watered (use the graph paper on the back page). Include all plants, trees, rocks and ponds. You want to illustrate every thing that will be watered and anything that might get in the
way of your watering on this plan.

Step 2

Take a close look at your drawing and determine the area that is to be watered. This is the time to decide if an area is to be sprayed or direct watered.

Step 3

Determine the style or styles of watering to be used. There are a range of heads each with their own specific application.

Spectrum 360 vortex spray
Sprays a 360 vortex circle. This spray has a fully adjustable cap that can be adjusted to a range of 0 to 10 foot spray, and from 0 to 20 gallons per hour.

Vari-jet shrubbler
Available in both 360 and 180 degree circle. This head provides the versatility of a dripper, bubbler or sprayer. By turning the head counter clockwise you range from a 1 GPH dripper to a 3 GPH bubbler or a finger spray with a maximum output of 10 GPH with a diameter of 2 feet.

Micro Vari-Flow jet spray
A Vari-Flow valve used with a jet nozzle. With the adjustable valve you can fit the jet nozzle to your job. From 16.3 to 28.8 GPH and 18.4 to 26.3 feet (with the 360-18 nozzle).

Step 4

Determine the amount of time per week you will have the system on. Remember that this is only a guide line. The exact duration and frequency of watering will depend upon temperature, wind conditions, soil types, plant variety and local restrictions. Mature plants have deeper roots, requiring a longer watering cycle. To double check your calculations after the system is running, dig down next to a plant to see the depth the water has reached. If the soil is dry within 12" of the surface, you are under-watering and more time will be required.

The hookup is your next step. Whether you use electric or manual valves, you will need a filter, pressure/flow regulator, and a back-flow preventer. A filter is needed because the holes in the different styles are so small that they will plug up very fast without it. A pressure/flow regulator is required because the working pressure of drip irrigation is between 10 and 20 PSI, and the flow regulator will adjust the flow to give the emitters the water they need - not more. The back-flow preventer is required by law to prevent the water in your pipes from re-entering your homes water supply.

Next look at your head layout on both your plan and site. Draw out where you think the supply line should be (you're the one who is going to be digging the trenches, so keep your layout to the minimum). You have completed the design which is the part some people find the hardest, now it's just a matter of putting it in. Take your time, and try not to get frustrated. All layouts get changed once the digging gets started. Before you back fill, run the system and see if it covers the area's and if there are any leaks (all of us have forgotten to glue a fitting or put a clamp on so do not feel bad if you do too). You are now ready to back fill your trenches. Besides checking your run time you are done for now.

Each spring you may have to update your system as you change plants or your lay outs.

One Piece Performance Chart
Recommended Operating PressureBlack .03 OrificeBlue .04 OrificeRed .075 Orifice
Spray Patternpress PSIFlow Rate GPHRadius FeetFlow Rate GPHRadius FeetFlow Rate GPHDiameter Feet
360 deg. Circle155.0
180 deg. Circle155.0
90 deg. Circle155.0
Recommended Operating Pressure 20 PSI
Vari-Jets w/Spray Cap

Spray Pattern
Desc. Pressure PSI. Flow GPH. 360°x18 Diameter Ft.180° Radius Ft. Diameter Ft.Mist Flow GPHMist Diameter Ft.
0.06 Orifice10Up to 16.3Up to 18.4Up to
15Up to 20.1Up to 22.6Up to
20Up to 23.4Up to 25.7Up to
25Up to 26.2Up to 26.7Up to
30Up to 28.8Up to 26.3Up to 10.6--
Recommended Operating Pressure 20 PSI
MI/FSFFinger Spray 3600-10GPH0-3 Ft.20 PSI
MI/FSHFinger Spray 1800-10GPH0-3 Ft.20 PSI
MI/VS360Vortex 3600-24GPH0-14 Ft.25 PSI
MI/RS12Mini Rotary (Blue)11.7 GPH19 Ft.25 PSI
MI/RS18Mini Rotary (Green)19.5 GPH21 Ft.25 PSI
Dripline Tubing
MI/DRIPIN1/4X121/4"" x 12"" Spacing1/2 GPH per ft.15 PSI33 Ft. Max. Run
MI/DRIPIN1/4X61/4"" x 6"" Spacing1 GPH per ft.15 PSI19 Ft. Max. Run