Drip Irrigation Part 2

Drip Irrigation Installation: Irrigation supplies, Sprinkler system, Garden irrigation.

Drip Irrigation - Installation

Drip Irrigation Installation | We discuss irrigation supplies for your sprinkler system for lawn and garden irrigation.

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Most homeowners have all the tools needed at home already, such as shovels, a straight-slot screwdriver, a Phillips screwdriver, and hammers. If you are planning a large-scale installation you will want to rent a Bobcat or other small excavator to help with all the heavy lifting such as installation of beds, bringing them to correct elevation, and the installation of the mulch layer.

For more information on planting bed installation, see the section on Planting Bed Design.

Isolation ValveOne specialty tool you should get is a Poly Pipe cutter. This tool makes cutting poly pipe of all sizes very quick and clean. It's well worth the few dollars you'll spend.


Start by Designing the Drip Irrigation System

Design Step 1: Refer to the Drip Irrigation Schematic Diagram below for guidelines on putting all the parts and pieces together for a typical drip irrigation system. This diagram shows only one zone. While most yards will require additional zones, this diagram should give you the general idea.

First of all, lay out your yard to scale on graph paper or use one of the simple landscape computer programs available to do this. Google Sketchup is a great, free tool. Just follow this LINK. to access it.

Be sure to document all of your main lines, valves, and bed layouts.

Design Step 2: Next, locate your water source line and then decide where you'll place your main irrigation control panel. Lay out your live main irrigation line around the perimeter of the house or yard and locate your separate bed zones in relation to this main line.

Green Living Made Easy uses the Weathermatic SL1600 Isolation Valveand we love all the control options that it has, plus the weatherstation modules to control wind and rain sensing, which conserves a lot of water. If your needs are less than what's offered by this this 12-zone controller, Weathermatic offers smaller units for much less money for smaller drip irrigation systems.

Design Step 3: Your mainline should not exceed 400 feet in length. Adjust your layout to stay below this maximum. Remember your mainline is the line that is live and the laterals come after the zone controller.

Isolation ValveDesign Step 4: Now layout your beds. These will be fed by lateral lines that should be constructed of 1/2" or larger poly pipe. These lateral lines will lead directly to the drip irrigation piping. The zone control valve is typically installed in the lateral line to control water flow from the live main to the drip zone.

You will need to feed the wiring from each of these zone controls back to the drip irrigation controller or sprinkler timer. It is best to try to group the zone control valves together in groups of two to four valves so they can be easily accessed in a plastic valve box with an accessible cover.

Isolation ValveDesign Step 5: Each drip zone should be designed to limit the maximum length of drip pipe to about 200' from the point where the water enters the Emitter Piping. Follow the drip irrigation pipe length guidelines below for rule-of-thumb bed areas and pipe lengths you can estimate.

    Also do not design a system that uses more than 180 gph per zone because of the friction loss in the 1/2" drip tubing.
    180 gph / .6gph = 300 emitters permitted.
    18" o.c. spacing of emitters and drip lines at 18" o.c. = 2.25 sq. ft./emitter
    300 x 2.25 = 675 sq.ft. of bed area served by one drip zone. This would be a bed approximately 25'x 30' per zone.
    -or- you can install a total of 270 lineal feet of drip line/zone, which is 180 gph / .6 gph emitters. Just keep the total line length to 200'

Remember that these are just guidelines or rule-of-thumb estimates you can make for a smaller systems. Larger systems should be designed based on hydraulic calculations.

Small systems Can Be Designed Using Rule-of-Thumb

Because small area drip irrigation systems are much more forgiving than overhead spray systems you can use many "rule-of-thumb" methods in the design of your system, eliminating a lot of the engineering calculation required.

You may be over-designing to a degree, but with the minimal costs of materials that will not be an issue. If you decide on a larger scale drip irrigation system, I would recommend that you turn to a drip irrigation supplier and/or a drip irrigation contractor for design services.

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Many times they will include this service for you, if you utilize their services or buy your materials from them. Be sure to qualify this with them up front before any time is spent on your project.

Here are some drip irrigation installation guidelines you can follow:
    Use .6 gph emitters for most soil conditions. For very sandy conditions use the 1 gph emitters.
    If you use the drip piping with integral emitters (which I prefer), place your piping at 18" o.c. The emitters are spaced this distance too so you should wind up with an 18" by 18" grid-work of emitters.
    In other words, one emitter services 2.25 sq. ft. of landscape bed. This works well for ground covers and smaller plants. For larger plants and trees you will need additional emitters.

To do this, branch off the drip line with a tee and place a circle around a large bush or tree. If the tree is quite large use 2 concentric circles of drip tubing. Allow for plant or tree growth when laying your lines. We recommend allowing about 8" to 12" from the edge of the plant to the tubing circle.

Installation of Your Drip Irrigation System:

Isolation ValveInstallation Step 1 Plan on running a live main irrigation pipe around the perimeter of your home or yard. This main would be hooked up to the Back-Flow Preventer, which is hooked up directly to the water source line. This line will give you a continuous loop of water that is available at any time because there is always water flowing into it.

Isolation ValveInstallation Step 2: Your Main Shutoff Valve should also be installed right after the back-flow preventer. This will allow you to manually shut down the system for maintenance or winterizing purposes.

Note: Refer to the Drip Irrigation Schematic Diagram below to give you guidelines of how all the parts and pieces go together for a typical zone.

Isolation ValveInstallation Step 3: Now is the time to install your zones. You should follow the maximum guidelines above for bed coverage. Lay out your lines in the 18" grid and hold it to the ground with the Ground Staples.


Isolation ValveInstallation Step 4: Tie the grid-work together with the end caps, Barbed Tees, and barbed 4-way connectors. I prefer the barbed connectors to the compression fittings because I have had a lot of compression systems blow out with a pressure fluctuation.

Isolation ValveInstallation Step 5: If your live main is a 1" poly pipe you will need 1" to 1/2" tees and Stainless Steel Clamps to place the tee into the main. I would recommend using (2) hose clamps on each side of the tee on the main because of the higher pressure.

Isolation ValveInstallation Step 6: Next, hook up a piece of 1/2 lateral poly and run to your irrigation control valve for that zone. Be sure the zone controlled is placed in a Valve Box for easy access and maintenance. Try to place several Zone Control Valves in this same box or "group" them together. From the zone valve, run additional lateral ploy pipe to the actual bed, if required.

Installation Step 7: Now is the time to install a header.  You can also install a grid-work of plants, and use individual lines for larger bushes, plants and trees.

Installation Step 8: Make all of your electrical connections from the zone control valves to the irrigation controller.

Installation Step 9: Once all your piping is installed, test the system under pressure and check for leaks. If you have none, place your plants and install 4" to 6" of mulch over the drip piping. Set your irrigation controller for the days and times that you require irrigation.

The amount of landscape or garden irrigation required will vary based on USDA zone, time of year, and type of plant materials used. Keep in mind that plants typically require more water to become established for the first year.

Curious about what USDA zone you live in? Click HERE for a USDA zone map. Once there,  click your state to get additional details.

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Drip Irrigation Diagram