How does Drip Irrigation Work?

Have you ever driven or walked by a beautiful garden with blooms aplenty, healthy greenery all around, and wondered, how do they do it? Much of the beauty of a garden or nice green yard IS indeed the work of a green thumb, but some of it is how the garden is watered, or irrigated.

The most efficient way to water a flower bed or any mulched landscape area is with drip irrigation, the brownish tubing that you can sometimes see under the mulch in a yard.

How does drip work, and why is it so great at growing plants?

This slow drip of water guarantees that water will get where it needs to go, down into the soil where it can be fully absorbed and distributed - no more wasted water!

Drip irrigation is the slow and steady release of water through the flexible piping known as dripperline, or dripline. Overhead irrigation, like rotors or sprays or old-fashioned impact sprinklers, covers plants with water, as rain does. Plants like trees, shrubs, and flowers actually prefer the targeted and controlled application of water, that brings water directly to the roots of the plants.

Because dripperline is more controlled, it is more efficient. Overhead irrigation is typically measured in gallons per minute (gpm), whereas drip irrigation is measured in gallons per hour (gph). This slow drip of water guarantees that water will get where it needs to go, down into the soil where it can be fully absorbed and distributed - no more wasted water!

The Origin of Drip Irrigation

In 1965, the Netafim group in Israel was the first company to develop drip irrigation, trying to grow crops in the Negev desert. Both farmers and innovators, the company learned that precision irrigation made the difference in successful growing. Out of that innovation, an industry was born. While Netafim continues to lead the industry with both products and sustainability, American companies Hunter Irrigation, Rain Bird, Toro, and many others have also brought new products and ideas to the drip irrigation market.

Applications

Drip irrigation can be used in a wide variety of garden and yard settings and is used in greenhouses and larger agricultural settings, too. The flexible pipe can be laid down in any number of configurations and can be custom designed and fit to your specific needs. Drip irrigation is usable with all different types of soil - clay, sand, silt or loam.

Because of the wide variety of terrains that can host irrigation lines, some types of dripperline is pressure compensated, which allows for a consistent flow rate, even going uphill, or on very long lines of plants. The non-pressure compensating drip tubing is fine for installations that are flat or have shorter runs.

Terms To Know

Dripperline - long flexible pipes with evenly space emitters & holes in them, designed to precisely deliver water. Typically, the holes, or emitters, are spaced every 6, 12, or 18 inches.  Dripline comes in both 17 mm and 12 mm sizes, and we encourage users to make sure they “stay in your lane” when ordering so that the couplers, tees, and other items are all the correct sizes. Blank tubing is also available to help convey water from one line to another.

Emitters & Drippers - There are 2 general types of emitters: “online” drip emitters known as “point source”, and “inline” drip emitters.

1. Online “Point Source” emitters: These are perfect for flow pots, trees, shrubs and native plants with wide and/or random spacing requirements. Depending on the plant’s canopy size and soil type, the number of point source emitters can be variable.
2. Inline emitters: The emitters operate in a similar fashion as online emitters, however, they come from the factory pre-installed inside the tubing. These emitters are molded/extruded inside the tubing and all that is visible from the outside is a hole for the water to come out.

Fittings - Tees, ells, and couplings will help you to install the drip line exactly where you want it.

Always double check that you are getting fittings that are the same size as the line you use. Clamps help to keep fittings in place in case of high water pressure. Staples are used to hold the tubing in place and are easy to install.

Pressure regulators - some people have the wonderful problem of having high water pressure coming into their yards. If your water pressure exceeds 50 psi, you will want to have a pressure regulator on your lines. A pressure regulator should be installed just after the water source, I.e. valve or spigot.

Filters - a filter on your main line will keep larger pieces of dirt and other contaminants from moving through your tubing and causing blockages.

Flush valves - debris, dirt, and algae can accumulate in the lines over time and should be flushed out of the lines at least once a year. These small valves are applied at the end of the line and can be opened to let everything pass.

End of Line - There are specific fittings that can be installed on the end of the dripperlines, such as a “Figure 8” - a piece that the hose fits through in loops to close off the flow of water. Lines can be crimped back and held in place with clamps.

Backflow Preventer - in certain municipalities and settings, preventing the flow of water back toward a home and the drinking water supply is very important. This type of valve prevents water that has been in contact with chemicals, animal excrement, dirt, etc. from moving backward into the main water lines.

Planning a Drip System

Planning your drip system can be fun! Draw your yard and garden on a large piece of paper and then play with the ideas presented here to come up with a plan for how to irrigate. Keep a running list of the fittings you will need. NetafimUSA.com has a calculator on their website that can help you figure out how much of which item you will need for your system. Netafim and some of the other companies also have design services that you can use, or, you can hire an experienced landscaper to help you reach your goal of a beautiful, well-irrigated yard.

One last consideration:  yard pests like voles can ruin your well laid drip line, and dogs can enjoy chewing on it! You can always make a shallow trench to put the line in and then cover it with a light layer of mulch, so that your pet cannot see the fun new toy you have installed.