Garden drip irrigation systems must be installed properly

typical garden drip irrigation system layoutIrrigation systems for landscaping are often installed improperly or don’t even exist. This observation is from my many years remodeling the landscapes of homeowner’s properties. Fixing an improperly installed drip irrigation system is a very common need for most landscape remodeling projects. Here is how to set up a proper garden drip irrigation system.

Proper Planting Design

An irrigation system is designed based on the layout of the plants. Proper irrigation design is best when the planting design is done with the irrigation system in mind. Plantings are not only selected for their form, shape and structure, but for their sun/shade requirements. The concept of planting zones will dictate the way the irrigation system is set up.

Create Irrigation Zones Based on the Plantings

Zones allow for the garden drip irrigation system to deliver water at different durations and frequency. Thus an irrigation station or individual valve is dedicated to a particular zone.  Examples of zones would be front lawn, rear lawn, trees, front shrubs, north shrubs, Xeriscape area, food garden, containers, etc. Note that each of these zones requires different amounts of water. Some require daily watering, others only once per week.

Determine Valve Control Box Location

Once you have a layout of which zones are to be irrigated, you then figure out where the valves should be located. The control valves will need a source of water, so where that point of connection is will affect the location of the control box.

On newer homes, the mainline feeding the house may have a pressure reducer and a line going into the house exposed on the outside of the house. Sometimes, they will install a stub out tee fitting for connection to the garden drip irrigation system, if not, you will have to tie into that mainline and run a line to your valves.

Locate the Irrigation Controller

The valves should be automated and controlled by an irrigation controller. The controller should have as many available stations as you have valves. The controller may be located indoors or outdoors and in either case, connected to a source of electricity. Control wire will run from the controller location to each of the valves so it’s not critical to locate the valves close to the controller.

Install the Lateral Lines and Emitters

Once you set up the mainline connection, your valves and controller, you can run your “lateral” lines that feed each of the zones. For a typical drip system, the lateral will be a ½” tube with separate ¼” tubing for each individual plant. The emitters can be anywhere from ½ GPH (gallons per hour) to 5 GPH.

Keep in mind that if you have one plant with a 1 GPH emitter and another with a 5 GPH on the same zone, one plant will be getting five times more water. Perhaps these plants were not properly chosen nor the irrigation system designed in conjunction with the planting design or installation.

The emitter output should be consistent among all emitters on each zone. This is determined at the time the plants are selected and designed. Since you can’t be perfect with this, some plants that are otherwise considered to have the same watering needs may require different amounts due to variations in soil moisture and sun exposure.

Does Your Planting Design Match the Irrigation System Design?

A proper garden drip irrigation system starts with the design of the planting plan. Unfortunately, too many landscapes are installed in a hodgepodge manner with no plan and consequently, the irrigation system is installed inefficiently resulting in higher maintenance and over watering. Unless you follow these guidelines, consult a professional for your next project to fix your existing system. Your plants will thrive being given the right amount of water.

For another post on drip irrigation systems, see my post called the top 10 drip irrigation mistakes and how to avoid them.


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