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Drip Irrigation Basics

Drip Irrigation is the best possible method for watering trees and shrubs, especially in dry regions or areas subject to drought, because it enables you to provide the exact amount of water needed by each plant and to place the water directly on the root zone. Also, if needed, fertilizer can be added directly into the system (see Fertilizer Injectors). Drip irrigation systems can be connected to any outdoor faucet. A hose "Y" provides an outlet for a hose for other uses. Also, this is the place to put a timer on the irrigation system.

Drip irrigation works with lower pressure than most home systems supply. So the first item to consider is a Pressure Regulator. The regulator is used to reduce incoming water pressure that is too high for drip emitters and fittings. Some city water districts or rural areas supply water at very high pressure. Homeowner pumps also can deliver water at too high pressure. The regulator should be sized to match the pressure range needs of the emitters in the drip system.

 Examples of operating pressure ranges for various emitters are as follows:

         T-tape—10-12 PSI

Non Pressure compensating emitters and 1/4” soaker dripline–10-30 PSI

Mini-sprinklers and misters—20-40 PSI

 

Next, choose a filter. Filters remove sediment and other particles large enough to clog emitters. The higher the mesh number, the finer the screen. Normal screen size for a drip system is 120-150 mesh, while T-Tape and misters require 200 mesh filtering. Stainless steel screens will stand up better to frequent cleaning so they are preferred for water supplies that contain sediment. Filters can be mounted vertically or horizontally.

Tee filters are used for smaller systems (480 GPH or less) with clean water. Y filters have larger screens and higher flow capabilities and will operate longer between cleaning than Tee filters.

 

Regulators and Filters must not be used before a timer or valve. (as they may suffer damage if kept under constant pressure)


There are two basic threads used on plumbing and irrigation parts: pipe thread and hose thread. Adaptors are used where you have to connect two parts with differing threads.  Some filters and regulators on this site have pipe threads—so be sure the  water outlet, and the filter and regulator you select are compatible.

 

Mainline tubing is used throughout a drip system to deliver water to areas or garden beds. It is inexpensive and made of soft polyethylene, designed to have holes punched into it (with Punch tools)  for connecting emitters and micro tubing.

 

Tubing hold downs are convenient for keeping tubing in place.

 

Easy loc Fittings work well with the soft polyethylene mainline tubing to adapt your delivery system to your design by allowing you to turn sharp corners, split the line, connect sub-main lines or connect emitter tubing. Use easy loc fittings to connect the tubing to the regulator and to end the line

 

The following example shows the correct parts sequence in a drip system:

"T" FILTER, PRESSURE REGULATOR, EASY-LOC CONNECTOR, MAIN TUBING. The "T"filter hooks up to water outlet (or to timer & water outlet)

In the actual watering of your garden(s) you have choices of:

Tape or emitter tubing or individually placed  emitters  --or a combination of these.

Emitters are small devices that are calibrated to portion out water at a slow and know rate (usually 1/2 or 1 gallon per hour per emitter). They can be added separately into tubing, or tubing can be purchased with emitters embedded. There are many kinds of emitters to allow for differing watering needs. Drippers cover a point source and sprayers and sprinklers can be elevated on a stake to cover widers areas (which is handy for watering areas of groundcover plants). Pressure compensating emitters ensure that the rate of drip does not vary due to distance from the water source or due to changes in elevation.

If your garden is planted in rows or in raised beds, the most logical choice to use is drip tape. It is the lowest cost drip system for rows and raised beds for commercial agriculture or backyard gardening. It can be used above ground, mulched or buried.

 

Tape-loc fittings are used to connect T-tape to the mainline tubing and to end the lines, mend broken tape or to turn tape at right angles.

 

In-Line emitter tubing  is generally used in landscape beds because it can curve around and even encircle plants. The 1/2” emitter tubing is also used where there is a significant change in elevation because it is pressure compensating.

(Pressure compensating means that the water distribution is equalized throughout the whole system regardless of row length or elevation changes.)

1/4” dripline emitter tubing is often more economical than tape for bed lengths of 12’ or less due to the lower cost of fittings and longer life of the product. If beds are raised and bordered by wood for example, it’s often easier to use 1/4” tubing due to its flexibility, and the micro irrigation parts (elbows) will get it up the sides and across the top of each bed. (see micro irrigation)

 

 There are many types of emitters to choose from, depending on each plant's or area’s specific need for water. There are drippers, sprinklers and sprayers with different spray patterns and misters to select that are ideal for any particular watering requirement. The use of different types of emitters will allow watering for container plants, hanging baskets, and for plants having different water requirements all on the same irrigation line.

 

Lastly--but this should go at the beginning of your system (before the pressure regulator and filter)--you may want to install a timer. A timer can be your best investment if you are not at home to turn the water on; or if you forget to turn it off. Easy to install and program, a battery operated timer will turn your water on and off at designated times to give your plants the steady, consistant watering they need for optimum health and production. There is even a low pressure timer that works at zero pressure—to run a drip system from a ground level rain barrel.

 

A word of advice: It’s always a good idea to sketch your system out to help you plan. Working it out on paper can save costly mistakes.

 

Further considerations:

You may want to start with one of our Drip irrigation kits. A great way to get familiar with drip irrigation. They can easily be added onto. They come with complete assembly instructions.

If you have groups of plants that require different watering frequencies you may want to split up your system into multiple zones to accommodate the differing watering needs. Similarly if your total irrigation flow is more than the maximum flow rate of the mainline tubing you’d also want to use multiple zones. This can be done with manual valves or an automatic timer having multiple valves.

 

If all this seems too complicated and you want us to plan your system for you, send us a sketch of your garden layout per instructions on Create my drip irrigation kit page. We’ll be able to give you a quote for providing you with a custom designed kit complete with all needed parts and installation instructions.