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DIY: Convert to Drip Irrigation

Intro: Sprinkler to drip conversion

Converting your sprinkler irrigation system to drip is easy if you know some key insights. This article is intended to give you the knowledge needed to make the DIY process efficient and successful.

Although this article is focused on retrofitting your existing sprinkler system, there is a lot of transferable knowledge that is useful no matter what kind of drip system you are setting up or maintaining.  For example, if you are looking for something basic to attach to your existing outdoor hose/lawn faucet, there are lots of simple hose drip conversion kits available.

This article was initially written for some of my neighbors who have been asking me about retrofitting their sprinkler systems… So then I figured I should share what I had with the rest of you all.

The many benefits of converting to drip

Retrofitting your sprinkler system to drip irrigation is one of the best financial decisions you can make for your yard.  The initial return on investment (ROI) is immediate and dramatic.

However, as an added bonus, many states have created rebate programs to further encourage people to convert to water efficient landscapes.  For example, in California residents can currently get $2 per square foot of grass-turf they replace for up to 3,000 square feet of turf removed (or as much as $6,000).

All of the above sounds great, but who knows how long those rebates will last.

7/25/15 Update:

Those grass replacement rebates mentioned above are gone.  As expected, it didn’t last. In the meantime, a waiting list has been created for the fall when/if more funds become available for the turf replacement rebates.  My new article provides the details and state rebate links.

However, there are still great rebates available for other water saving products.  I just wrote and updated article outlining the ways to cash in. Check out the article Water Saving Rebates: Get paid to save water

A related note, this is an interesting article covering the subject of how much Americans invest in their lawns (see below)

 

Other water saving incentives: 

As a different incentive approach, I have also read that some water utilities will exempt landscapes from drought water restrictions if their property is irrigated with drip.

Perhaps just as important to a gardener is the benefit that the more focused deep watering of a drip irrigation results in stronger, happier and healthier plants.  In addition, the spray from traditional sprinkler systems can cause mold growth on leaves and damage buildings… and this can be avoided with targeted drip irrigation.  Finally, a wonderful unintended consequence of focused drip irrigation is less weeds to battle.

Finally, many areas of the country (and parts of the world) are running out of water.  When this essential element of life is gone, there will be significant economic and social issues.  I recently saw a video interview with Thomas Friedman (NY times columnist and book author) who specifically addressed this issue. Friedman explains how a lack of water/drought has fuelled many global conflicts and wars, including the current Syrian revolution.  Here is a link to that compelling video interview of Friedman about water security and war.  On a positive note, there is technology being developed to actually extract water from the air that can be used for irrigation and consumption. This is truly an exciting technology.

California running out of water

California running out of water (image reference: http://www.bewaterwise.com)

 

Personal irrigation experience/background

When I was in college, I worked for a landscaping company to pay for school.  Between the heavy lifting, I also informally learned on the job about irrigation.  In the years since, I have broadened my knowledge from talking with friends working in commercial farming and agriculture.

More recently, I have moved to a home in Southern California that was initially watered by 12 zones of sprinkler irrigation.  The land was covered with white PVC pipes, sprinkler heads and weeds.  Because the water bill was scarier than a Stephen King novel, I made it a high priority to personally convert the sprinkler systems to drip.

I am happy to report that the cost of the irrigation conversion quickly paid for itself after the first water bill (and that was without any rebates).  My water use is now about 80% lower than it was before the drip conversion.  That’s really a huge change.  More specifically, in the summer, I spend a little over $100 a month on my water bill for a property that is over an acre in size.  Amazingly, this staggering water savings happened despite the fact that the property is now packed full of beautiful fruit trees and previously the land was covered in weeds.

I am not certified irrigation expert, although in the process of writing this article I have discovered that there is a set of certification programs out that can help contractors to further develop their credibility and expertise.  If you are looking to hire someone to install your irrigation system, I would suggest that you ask if they were certified in one of these programs.

None the less, I do have many many years of experience and this free article is jam packed with (what I consider to be) great tips and insights for the average home owner.  Even if you want to hire someone else to install your irrigation, knowing the info outlined in this article will help you to avoid getting ripped off… or at the very least it will provide you with a foundation of knowledge for an empowered conversation with a contractor.

Overall, I am just trying to share what I have learned over the years because I believe water conservation and water security are critically important topics for our environment and our country.  Frankly, water availability is a matter of national security.  The more people that can be empowered to conserve water the better. I hope this article can be a useful reference tool and I also look forward to hearing about your own experiences, feedback and suggestions.

Bearss lime cultivation

Bearss lime ripe for home picking

Article outline

  1. This article will start with a general outline of a typical sprinkler irrigation system that might be set up for your home.  This is intended to provide you with some foundational knowledge and terminology.
  2. Next, you will see a short “before you begin/planning” section.
  3. Following that section, is a list of the supplies that you will need to make the conversion to a drip irrigation system.
  4. The text is then organized into 4 basic steps to completely convert to an drip irrigation system.
  5. Finally, there is a list of general water saving suggestions at the end of the text.

Throughout the article, additional useful pearls of knowledge are added in when relevant and presented in green text. Potential pitfalls and warnings are presented in dark red text.

 

1. Your existing irrigation system anatomy

Looking down into your valve box can be a bit intimidating.  Therefore, the following is intended to provide some general info to demystify the system you already have in place and provide some basic terminology.

Simply put, a proper irrigation system is designed to safely divert home water to your yard.  The components of the system are all about controlling the flow of that water.  Most irrigation systems have a similar basic layout and the following text is a general synopsis.

irrigation valves

Looking down into the inside of a valve control box.

Water is diverted from the home water source to a series of irrigation control valves (sometimes called sprinkler valves).  A group of irrigation control valves running off the same supply line is called a manifold.  Each irrigation control valve represents an irrigation zone that waters a different part of the yard.  These irrigation control valves usually have a solenoid attached to them.  The solenoid is basically a motor that acts as a valve “on-off” switch.  This solenoid is connected to and controlled by your irrigation controller/timer system via two wires.  All of your irrigation control valves should be covered and therefore protected by an irrigation valve box.

The irrigation control valve may or may not have a backflow prevention device built in to help keep external dirty irrigation water from flowing back into the home water source.   If the valve does appear to have this protective mechanism built in, this whole irrigation control valve is more specifically called an “anti-siphon valve”.  However, even if you do have an anti-siphon valve, it may still be required (and a good idea) to have additional backflow prevention measures built into the irrigation pipeline.  This is especially important if you are pushing water up a hill or slope and therefore gravity will want to suction all that water in the pipes back down towards the house when the water is turned off.

If the irrigation control valve does not have a backflow prevention device built-in, it is probably an “In-line valve.”  When using in-line valves, your irrigation pipeline will definitely need to be protected by some sort of separate backflow prevention solution such as an anti-siphon device.

Regardless of what type of irrigation control valve you have, it will control the flow of water from your home to a specific part (zone) of your yard. Water is typically directed from the irrigation control valve to a typical sprinkler system via schedule 40 PVC pipe.

The last backflow prevention mechanism that was built into my irrigation pipeline (that goes up a slope) is an atmospheric vacuum breaker.  This vacuum breaker is built at the apex of an elevated connected series of PVC pipes which is shaped like an inverted “U.”  Depending on your local codes, landscape terrain, and overall setup, this additional backflow mechanism may or may not be necessary.  But if it is already built in to your existing line, it is probably there for a reason and I wouldn’t take it out.  For the sake of the instructions in this article, we are assuming that this vacuum breaker is a part of the existing system that we are retrofitting.

The vacuum breaker has an interesting internal mechanism (Portland Water Bureau has a nice cross sectional image of the device on their site).  When the water is turned off, the pressure decrease in the pipeline causes the breaker valve to open up.  This opening breaks the suction of the water in the PVC pipes, in a way that is similar to how a hole in a drinking straw would break your ability to drink your fruit smoothie.

If you want to build the entire system from scratch, this Toro guide has a lot of good information even though it was written specifically for sprinkler installation.  The IrrigationTutorials.com website has a ridiculous amount of information about irrigation systems, including installation.

2. Before you begin/planing

Although landscape planning/design is out of the scope of this article, I wanted to add in a few thoughts to consider here.

I design my landscape so that fruit trees are easy to get to. I want to make their care and harvesting as easy as possible. Therefore, I usually plan/create walking paths first and then plant the fruit trees accordingly. Areas that are more difficult to get to (because of a steep slope or rocky terrain, etc) get drought tolerant plants that will take care of themselves.   I try to group plants together with similar watering needs so they can be fed by the same irrigation zone. However, as geographic conditions dictate, I will sometimes have irrigation zones cross over each other to water the different plants appropriately.

Pearl of knowledge:  Some parts of a particular property may have different municipal easements for sewer or water. These are usually areas where you can only plant shrub type of growth. This zoning information should be part of the informational packet you got when you bought your home. If you cant find this paperwork, the water authority will come out and stake your area for you if you have any questions or want to be exact about things.

Important Warning: Cable and power lines may also be underground where you want to plant a tree, etc.  Therefore, before you start digging, it is always a good idea to call the phone number 811 (their moto is “Call Before You Dig”).  They are more than happy to come out to show you where those lines are buried on your property so that you don’t get into trouble.

Drawing out a property map plan ahead of time is really useful.  This helps you to see how the different zones interact and overlap with each other.  It also allows you to see how what supplies you need to get the job done. Google maps is a great resource for this planning.

Important Warning:  Water within irrigation pipes/tubes can easily become contaminated with microbes, toxins and other contaminants.  As a result, water within any irrigation line is considered non-potable or dirty water.   Under normal conditions, this is not a big deal for your plants, but it can be very harmful to people. 

Therefore, any irrigation system should have a robust backflow prevention system builtin to keep contaminated irrigation water out of your house water (or well water).   Any backflow prevention device is designed to allow water to flow in one direction but not back in the reverse direction.  Note; a simple valve by itself is not adequate to prevent backflow.

To me, this backflow prevention safeguard is the most important component of an irrigation system. Local water authorities have specific codes about how backflow prevention mechanisms should be set up.  If your initial sprinkler system was setup correctly, then you should be set.   However, I have heard of examples where installers have missed the mark on this safeguard.  Therefore, it is better to be safe and check with a professional.  I dont want you getting sick. 

As a result, before turning on your irrigation line, please confirm that your completed drip system is set up to meet or exceed your local water authority code.  One that note, one option is to give your local water authority a call and ask them to come by your place to check out your setup.  In my opinion, you already pay them a significant amount of money, and therefore you earned this service.  Sorry about the phone calls water authority guys, this is the right thing to do.  Home water safety should be well within your water authority’s scope of roles and responsibility.   Alternatively, you can hire a certified irrigation specialist to set things up and confirm it is all safe.

For additional reading, I recently found this rather complete website page that outlines different backflow prevention options.  Wikipedia also has a general overview article on the topic of  “Backflow Prevention Device.” 

 

3. Supplies you will need to convert to drip irrigation

Optional supplies:

 

4. Steps to convert to a drip irrigation system

 

Step A.    Build the drip irrigation apparatus.

The drip irrigation apparatus is composed of a few basic parts.

  1. PVC Reducing adapter (with a slip side that connects to the PVC pipe and the threaded side that connects to the filter).
  2. Screen filter
  3. Pressure regulator
  4. Compression adapter
  5. Depending on what components you get, additional pipe adapters may be needed to connect some of these parts.

New development: There is a new product available that combines the filter and pressure regulator into one unified device. I have seen this called a “Pressure Regulating Filter” or a “filter/pressure regulator”

drip irrigation filter options

On left side a blue circle surrounds a “Pressure Regulating Filter” which does the same job as the separate filter and regulator inside the red circle on the right side.

I connect the four parts in the order listed above (and shown in the picture below). Although there are differences in opinion, I believe the pressure regulator should be in-line/downstream after the filter. This orientation allows the filter to protect the pressure regulator from getting clogged up.  The filter and pressure regulator should have an arrow on the side of them that indicates the direction of water flow. This arrow guides you to connect these parts in the right orientation.

Important note: Read the manufacturer instructions which will take president over any information presented in this article. 

how to set up drip irrigation

Drip irrigation set up (without labels)

 

DIY drip irrigation

Drip irrigation set up ( same picture with labels). you can click on image to enlarge.

Pearl of knowledge:  Make sure you know the diameter of the PVC pipe that you are going to be cutting and plugging into.  The diameter of the PVC pipe is normally printed on the outside of the PVC pipe.  This outside diameter is the size that you want the female slip part of “Reducing Female Adapter” to be (this is part #1 listed above).  Most of the time, the standard threaded part (that attaches to the filter) will be 3/4 inch.  The smooth slip part of the adapter (that attaches to the pipe you cut) is often 1 inch, but not always.  If these are the sizes for your system, the complete name for this for this part should be listed as (Reducing Female Adapter 3/4″ x 1″ ).  But again, just check your PVC pipe measurements to be sure. 

Convert sprinkler irrigation to drip irrigation

Some of the more common diameters of PVC pipe available. Pipe diameter sizes are labeled on the outside of the pipe (see red arrows drawn on the picture). Sizes from the top to bottom of the picture: 1-1/4″, 1″, 3/4″, and 1/2″. (You can click on the image to enlarge)

 

Setting up drip line

Left image: PVC pipe going into the slip side of the adapter. Right image: Female threaded side of same adapter going into the filter. Note: glue on left and tape on right still needs to be added.

Pearl of knowledge:  Before hand tightening the threaded parts together, you need to carefully wrap a few layers of Teflon tape sealer on the male pipe threads.  This will prevent leaks at the threaded points of connection.

Potential Pitfall:  The parts of the drip conversion system apparatus are connected to each other by threaded pipes. The diameter of the pipe is usually a standard 3/4 inch. However, confusingly these threaded pipes are available in two different types of threading. 

You may find either “pipe thread” or the wider spaced “hose thread” (pipe thread is the way to go in this situation).  It is important to be mindful of the different options when getting your supplies because pipe thread and hose thread don’t connect to each other.  In addition, the different components are often found right next to each other on store shelves and the parts can wonder into the wrong box.   Therefore, you need to be vary diligent to make sure you pick the right parts.  In this article, I have only created links to the desired parts for this project.  None the less, if you buy the wrong stuff at your local store and loose your receipt or something, you can also get conversion coupling that will allow you to connect differently threaded parts. 

Step B:    Cut and paste:

First, locate the first sprinkler head in your existing sprinkler pipeline (this should be the sprinkler head that is closest to the irrigation control valve in the pipeline).

From that first sprinkler head, follow the pipeline back to its irrigation control valve.   When you follow the pipeline back, you should be looking for some sort of backflow prevention device.  You want to make sure that you install the drip conversion apparatus downstream of the last backflow prevention device in your existing system.  For me this location is just a few feet before the first sprinkler head.

By example, my existing sprinkler irrigation pipeline was already set up with two separate backflow prevention devices built into the system that takes water up a slope.  At the start of the line, each of my irrigation control valves has a backflow prevention device built in, and therefore it is more specifically called an “anti-siphon valve.”   In the pipeline just after the valve and before the first sprinkler head, I also have an atmospheric vacuum breaker built in.  This vacuum breaker device is located at the apex of an elevated connected series of PVC pipes which is shaped like an inverted “U.”   Note a vacuum breaker should be installed and secured to be level.

I install the drip conversion apparatus on the far/downstream/down flowing arm of this inverted “U” shaped vacuum breaker apparatus (see picture).

Converting sprinkler irrigation to drip

Cutting the PVC pipe downstream of the last backflow prevention device. In this case it is a vacuum breaker (partially seen in the top left hand side of the picture)

Once you have found the optimal location to install the drip conversion device, cut the PVC pipe with your PVC pipe cutting tool.  Discard the far end of the pipe that you just cut (the part which has all of the sprinkler heads on it).

Pearl of knowledge:  Using a saw is not the way to cut PVC because it may break the PVC pipe and will result in the formation of multiple small shaving that can clog your irrigation system emitters.  Besides, it is also really easy to cut PVC pipe with the specially made PVC pipe cutting tool.  As an added bonus, I have found that these PVC pipe cutting tools are great to cut open raw macadamia nuts. Yum.

Drip irrigation conversiontools

I also use the PVC pipe cutting tool for the off label function of opening macadamia nut shells. Just make sure the cutting tool is clean of chemicals before you use.

Potential pitfall:  I have seen where the screen filter in some setups has been oriented in such a way that it barely fits into a tight location (such as between PVC pipes).  In this suboptimal position, the filter cover can’t be unscrewed and therefore the internal filter cannot be cleaned or checked for holes.  Therefore, make sure that you connect the filter in a way that they can be easily unscrewed for cleaning.  

Warning/Important Safety Note:  As was mentioned earlier, backflow prevention is a big deal. Dont navigate the poly tube so that it is at an elevation above the last backflow prevention device in the line.  Most codes indicate irrigation line should be 6 inched to a foot below the last backflow prevention device. Please confirm that your system meets or exceeds your local water authority code.  

 

PVC Glue:

Read and follow the instructions and warnings on the glue and primer bottles.

At this point, you have already installed a slip/threaded pipe coupling to the top of your drip conversion apparatus. Take a look at where the recently cut PVC pipe will fit into the slip pipe coupling.  Prime both the cut PVC pipe end and the slip side of the coupling where they will connect to each other. Do this by painting on the primer with a brush applicator provided in the primer jar.  Then paint on the PVC glue to the same area in the same way.  Quickly connect the PVC pipe and the slip end of the coupling by pushing them together all the way and giving a 1/4 turn at the same time.

Pearl of knowledge:  This glue dries quickly so you have to work fast.

Warning/Safety Note:  This glue and primer smells really toxic so try not to breathe it in.  The best option for me has been to hold my breath, work fast, and then walk away.  Having everything organized and ready to go before you open the primer bottle and glue bottle is key to minimize inhalational exposure.  Some people will use a mask as well, but don’t bother with dust masks because they won’t block these volatile fumes. The larger more complex professional masks may help but I can’t confirm that.

Warning/Safety Note:  Also try to keep this stuff off of your skin. Some types of gloves may help, but the glue and primer can melt plastic gloves. I learned this the hard way and yes it is painful. Fabric/leather gardening gloves may be an option but they may make it difficult to work and may not completely protect your skin from a big spill.   The best bet is to be very careful and organized during the primer/glue stage of this project.

Now that you have glued the parts together, you can walk away and let the glue harden (and let the fumes dissipate).

Pearl of knowledge:  Painting PVC pipe will help to protect it from damaging UV rays.  If you use flat camouflage paint, it will also help the pipes blend into the landscape. You will likely need to prime the pipe first to make sure the paint sticks. I also like to label my pipes with vinyl number stickers so it is easier to keep track of a particular zone. 

Drip conversion set up

Complete installed drip conversion apparatus (bottom right) and vacuum breaker (top left). PVC pipes have also been painted with flat camouflage paint.

Step C:    Poly tube:

The drip mainline tubing is called poly tube (short for polyurethane tube).  This black tubing is also sometimes simply called “drip line” or “drip tubing.”  This tubing is what carries water from the drip conversion apparatus to all of your plants.

Poly tube is easily cut with regular scissors or even hand garden trimmers.  Connecting the poly tube is pretty easy too. You basically push and wiggle the cut end of the poly tube into the connector (aka fitting). I prefer the compression type connector over the barb type connector.

Convert to drip line

A bag of barbed poly tube connectors

irrigation splitter

Poly tube compression connector “T” Splitter.

You can use different types of compression connectors to help to navigate the poly tube to where you would like it to go.  From the drip conversion apparatus, I usually add in a 90 deg elbow connector at ground level to get the line started without a kink.   With “T” or “X” types of connectors, you can easily split the line to go in multiple different directions.  However, the overall length of a single irrigation zone should be limited to a total of 200 feet.

Pearl of knowledge:  Some have suggested that connecting the poly tube and coupling is easier if you first dip the poly tube end in hot water to soften it up.  However, I would highly recommend against this practice because it can cause the tubing to warp to a smaller size leading to an unstable fitting connection that can leak or blow apart.

After you plan out your watering needs, just roll out the poly tube to where you want it to go (but make sure it does not kink). If you are navigating the poly tube to take a sharp turn and it wants to kink, just add in the appropriate compression connector.

Pearl of knowledge:  This black poly tube will expand and contract as a result of daily changes in temperature.  This will cause the poly tube to wander if it is not secured in place.  In addition, unsecured poly tube can be a tripping hazard and eyesore.   Heavy duty metal garden landscape staples are the best way help keep the poly tube where you want it.  An interesting thing about these metal staples is that they tend to develop a ball of adherent rust and soil at the ends which acts like an anchor keeping the staples in place.  Alternatively, there are also curved plastic stakes that you can purchase to hold the poly tube in place.  However, in my experience, these plastic stakes don’t seem to hold the tubing in the ground as well.  If you want to save some bucks, you can cut up wire coat hangers and bend them to the shape of a garden landscape staple to do the same job.  Rocks can keep the poly tube in place too, but if they are too big they may flatten the poly tube making it ineffective.

Pearl of knowledge:  I have heard that some thirsty coyotes (and other animals) may develop a taste for poly tube. Basically they have discovered that chewing on water filled poly tube can provide a thirst quenching treat.  Therefore, keeping the poly tube out of site helps to reduce that gnawing risk.  On the other hand, I have also seen where gophers have eaten into poly tube that is buried underground.  So now what do you do?

There may not be a perfect solution, but I have split the difference in my poly tube placement approach. With a small hand pick, I dig a very shallow trench for the poly tube to sit in, staple the poly tube down, and then cover it with mulch.  This also helps to extend the life of the poly tube because the mulch protects it from the degradative effects of UV sunlight.  When properly staked down, this technique also keeps the poly tube out of the way as a tripping hazard.

When you navigate the poly tube to a tree you have a few options.  For me, the easiest method is to make a simple loop of poly tube around the root zone of each tree.  Alternatively, you could just have the poly tube go straight by a tree and then add emitters and spaghetti tube extensions to reach the rest of the root zone.  This straight option will save you a bit of poly tube but it will will likely take more time and supplies to set up in the end.  I have also seen where some people use lots of poly tube fittings to make a fancy poly tube square around a tree… but I strongly believe that this last option is a total waste of time and money in extra supplies.

Setting up a drip line

Loop of poly tube positioned for an expected future planting

 

Pearl of knowledge:  Because of gravity, the parts of an irrigation line that are lower in elevation will collect/hold more water when the system is turned off.  Therefore, those plants supplied by the lower parts of the poly tube will end up getting more water as it continues to drain out through the emitters after the water is turned off.  Planning irrigation zones/lines to run horizontal to a slope will help prevent this problem. Placing slower flow emitters at the lowest point of a line can also help adjust for this effect. Snaking the poly tube to look like a sine-wave will also help to distribute the areas where water collects in lower portions of a line.  

Warning:  Poly tube should not be placed/run at an elevation higher that the highest backflow prevention device in that line. Most local codes dictate that the irrigation line needs to be a specified elevation below the highest backflow prevention device. This elevation buffer is usually on the order of 6 inches to 1 foot (depending on the local code). 

Poly tube end clamp:

You will need to somehow stop the flow of water at the cut end of the poly tube.  There are several solutions available to do this, however, the most reliable and cheapest option I have found is a simple plastic figure-8 end closure.  Just insert the figure-8 into the end of the poly tube, fold over the tube and secure with the other side of the figure-8 loop.

This setup also makes it really easy to unfold the end of the poly tube to flush out the system.  On that note, the line should be flushed after the initial setup in order to clear the irrigation line of any debris.  It is also recommended that each line gets flushed annually to keep things clean.

Just for completeness here, there are other ways to cap the cut end of the poly tube. On the slightly more expensive side, there are products called “compression end caps” “hose end plugs” or “end caps” that will unscrew after installation to allow you to flush the system.    On the cheap side, some people have used duck tape and/or zip ties to hold the folded end of the poly tube in place.  However, theses cheaper solutions will eventually wear out, and when they do, you will have a big flood after they unexpectedly fail. In addition these initially cheap duck tape/zip tie options will require you to destroy the solution each time you flush the line.

Drip irrigation

The poly tube is shut with a figure-8 end clamp on the left and it is opened on the right.

 

Poly tube sizes:

There are several different sizes of poly tube available on the market.  Confusingly, in the US, the sizes are listed in Metric and English measurements and the stated conversion between the two measurement systems is not always that accurate. In addition, the different size tubes may look very similar but they are definitely not cross compatible.  The fittings that you use for these different types of poly tube are also different/specific to the size of the tubing available.   Using the wrong sized fittings can result in an unexpected blowout/disconnection in the line.

The most commonly available sizes of poly tube that I have seen are outlined below.  Measurements are for the outside diameter of the poly tube.  Sizes are listed in millimeters and (inches”).

The two most common sizes I have seen are:

16mm (0.620″ or more accurately 0.629.”)  Confusingly, depending on the manufacturer, this is sometimes also labeled as 1/2″ or 5/8″

18mm (0.720″ or more accurately 0.709.”)  Confusingly, depending on the manufacturer, this is sometimes also labeled as 0.700”, 0.710, 1/2″ or 5/8”

Other sizes you might see:

12 mm (0.455″ or more accurately 0.472.”) Sometimes also called 3/8”

24mm (0.940″ or more accurately 0.945.”) Sometimes also called 3/4″

I know this is a total pain in the butt.   My suggestion is to go with one of the most common sizes of poly tube available and stick with it.

Poly Tube drip irrigation

Poly tube

Step D:    Emitters:

Emitters are what allow you to control the amount of water that flows out of the poly tube to your plants.  There are lots of different styles and types of emitters.  Each emitter has a different flow rating that should be labeled in either liters per hour (LPH) or gallons per hour (GPH). Basically, the higher the number the more water they will put out in a given time.  These emitters are also color coded based on their flow rates.  However, just to confuse you, different manufacturers use different color codes.

If you have hard water, your emitters may clog up at some point.  This is basically the same type of thing that happens to your shower head or sink faucet.  Even without hard water, emitters can clog with dirt and debris.   However, the filter you installed earlier should help with most of this.  Some emitters are easy to fix when they clog up, others have built in cleaning mechanisms and others can’t be fixed.  The flag emitters and bubblier emitters can be pulled apart and cleaned fairly easily.  If you have an emitter that gets clogged and it can’t be cleaned easily, you can just pop in another emitter next to it or pull it out and add in a goof plug.

Note:  There are different styles of goof plugs available. I highly recommend getting the ones that have different size diameters on each end (see link and picture below for reference).  If you pull out an emitter, you will have to use the fatter side of the goof plug. In contrast, if you just want to stop up a hole you only made with a punch tool then you can use the smaller side of the goof plug.

Fix a broken emitter

This is a series of pictures taken while fixing an emitter that broke off at the emitter barb neck. I have found that once an emitter has been pushed into a hole, you have to use the wider side of the goof plug to make a complete seal.  In the last picture to the right, you can see the leak that happens when you use the smaller side of the goof plug to fix a punch hole that an emitter has previously lived in. (You can click on the pic to enlarge)

 

I prefer the flag type emitters for small plants because they are easy to clean if they get clogged up.  I have also personally had a lot of button type of emitters break apart which results in an unwanted and unexpected torrent of water flow (see above series of pictures).  The bubblier type of adjustable emitters are great for larger plants/trees because they put out a lot more water per unit time.

emitters for tree irrigation

Bubbler emitter

 

Potential pitfall:  There are also micro-spray emitters (aka micro-sprinkler emitters) that can look almost identical to the bubbler emitters. These micro-spray emitters distribute the water in a mist and this is typically not what you want if you are trying to irrigate a tree.  Therefore, you need to diligently look at the label when you are buying these types of emitters so you get the right one.

Emitter tubing:

There is also this stuff called emitter tubing (aka 1/4 inch tubing or spaghetti tubing) that can help with the positioning of your emitters.  Basically emitter tubing allows you to put an emitter further from the main poly tube line. You connect emitter tubing to the poly tube via an emitter barb connector.  Emitter tubing is necessary to use with some types of emitters that have a stake built in to them (note: these stake emitters usually have the necessary barb connector added into the unit).

Emitter tubing can be a great solution for other types of emitters as well, but the longer the tubing is, the more likely it will become a problem.  For example, the emitter tubing can easily be tripped over and pulled out.  I have also sliced a bunch of them up when weed whacking around a tree.  Emitter tubing is typically available in black and brown colors.

Emitter tubing

Two different colors of emitter tubing heald in my hand

 

Irrigation emitter setup

Some emitter setup options. The elbow style barb can help to keep the tubing at a lower level/profile and out of the way.

Punch tool:

You will need some sort of punch tool to get the emitters connected to the poly tube.  The business end of a punch tool is pretty simple.  It is basically just a small circular cutting blade that is designed to create a small hole in the poly tube that is the right size for the emitter barb to go into. There are lots of different styles of punch tools.  They mainly differ in the way the handle is set up.

If you punch a hole into the poly tube and change your mind it is not a big deal.  Simple goof plugs will allow you to fix a misplaced punch hole.

emitter punch

Emitter punch tool just made a hole in polytube for another emitter

Potential pitfall:  The more emitters you put in a given poly tube line, the more water they will pull from the line.  Therefore, if you have too many emitters per zone, you will lose water pressure in the poly tube line and therefore the other emitters in the line will not have enough pressure to work at their rated capacity. As a result, you will have trouble watering your plants in that line.  Too many emitters in a particular line is a common error.  This emitter threshold depends on several factors such as the baseline water pressure/flow of the line, the pressure regulator you installed, and the combined rate of flow from all the emitters in the system.

Emitter placement:

The best place to put emitters is about midway in the trees root zone (The root zone is a circle around the trunk of a tree that is about as wide as the trees branches).

If you are irrigating plants on a slope, position the poly tube and emitters on the ground above the level of the plant so the water will absorb into the soil with gravity and then soak tangentially into the main root zone.  Creating a hole or basin for the water to collect (located above a plant on a slope) can help prevent the water from running down the slope like a stream.  Using slow flow emitters that are left on for a longer time will also help the water to soak in on problematic slope areas.

Potential pitfall:  Don’t put emitters too close to trunk of tree.  Watering the trunk of a tree can result in fungal infection and rot that will kill a plant.

Potential pitfall:  Don’t bury emitters under the ground. This will clog up an emitter and that buried emitter may also pull dirt into the mainline which will then clog other emitters downstream.

5. Final thoughts on making the most of your water:

  • The most efficient time of day to run your irrigation system is in the early morning.  This gives the water time to soak in before the sun starts to evaporate the water on the surface soil.
  • Survey your entire system (when it is on) regularly to look for broken or faulty parts.
  • On a similar note, many water authorities offer an “irrigation audit.”  This audit may be free or provided at a minimal cost.  This is basically a complete review of your irrigation system to see if there are parts that need to be fixed. They may also show you how you can optimize things like your watering schedule.
  • Adjust your irrigation timer/controller for the season and/or weather patterns.  To make things easier, buy a Weather Based Irrigation Controller.  Local water authorities may give rebates for the purchase of these water saving devices.  An electronic rain sensor that detects actual rainfall can be added to most irrigation systems and further help to automate the process for you.
  • Enriching the soil with composted organic matter at the time of planting will help to reduce your plants water needs. For a more complete outline of the best planting tips, check out my recent article on the subject.
  • Install water saving appliances.
  • Shower with someone to save water.
  • Check out some of the rebate offers mentioned at the beginning of this article. Even if those rebates arent available for your location, the featured products are still pretty great.
Maintaining a drip irrigation system

A broken emitter misses the tree and wastes water.

About Thomas Osborne, MD

Dr. Osborne is a Harvard trained Radiologist and Neuroradiologist who loves to share his insight about medicine and gardening.

2 comments

  1. Just wanted to thank you for putting this all together. I have been attempting to use drip irrigation and convert existing sprinkler systems to drip for some years now (at 2 different houses, with various methods of conversion), and have never read such a clear explanation of what all the different parts are, and what their purpose is. NOW I understand and am ready to tackle my project! Thank you!

    • Thomas Osborne, MD

      Thank you for the great feedback.
      Great to hear.
      As a side, my water bill was cut in half the first year I started the conversion.
      The next year, after more conversion, the bill was cut in half again.
      Plants are happy.

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