Drip Irrigation and How to Hide Your Manifolds: Bonus How to Find Your Drip Manifolds After Someone Hid Them

Ordinary irrigation uses spray heads to simulate rain over a garden. Water goes to plants, weeds, sidewalks, and walls. Errant irrigation spray discolors and potentially damages walls. I observed many sidewalks being watered, yet I have never seen them grow. Drip irrigation only waters desirable plants using strategically placed drips. Plants prefer the water on the roots not the leaves. Drip reduces water use, limits weeds growth, and keeps sidewalks and walls dry. Many jurisdictions encourage drip irrigation by excluding them from drought restrictions.

To reduce our water use we recently converted one zone of our irrigation from spray to drip. The sixty-foot rock garden was decorated with flowering plants, cactus, and palm trees. The previous owners had installed spray heads, which at the time was the economic choice.

While scoping the job, I quickly realized that to maintain this system I needed some new techniques I had not seen before. First, because each sprinkler head was to be replaced with a multi-port drip manifold servicing several plants, I need to some way to find which line serviced each plant. Second, I learned in my previous experiments that drip emitters tend to clog. Finally, because we wanted the natural look, the manifolds would be hidden. Hidden is nice, unless you need to adjust or fix something. I need a way to find the hidden manifolds.

Having experience in large networking and control system the solution to the first problem was obvious, use wire markers on each end of the drip lines, and on the distribution hub. If there were a problem with a plant’s water supply, I could quickly determine the controlling port on the distributor.

The solution to the second problem also came from networking experience. To improve reliability many large networks feed from two directions. To reduce clogging problems I would feed the drips from two directions with a loop around each plant. Further, I could place this loop at the plant’s drip line. The easiest way to identify the drip line is to observe the plant’s shadow at noon. 

The phrase drip line is used for both the irrigation tubing and plants. To reduce confusion, I will specify plant’s drip line as the circle around the plant, otherwise I am referring to the irrigation tube.

The final problem required some out of the prox thinking. I have extensive experience with proximity cards, readers, and systems.  Typically, you give badges to employees, fix the readers at entrances and use the number read from the tag to release a door. The badges are very tough, sealed, and powered by the reader. So why not fix the badges to the drip manifold and move the reader? Bonus: Because the reader technology we are using is being phased out, we can save e-waste by upcycling the readers from old corporate installations.

Some people might enjoy a simple drip irrigation without electronics. Please feel free to omit the steps marked Geo-Location (Steps 5, 6, and 7) to exclude the reader part of this project. These can be added later.

Retrofitting older sprinkler heads you will need a number of drip manifolds, ½ inch plumbing nipples, ¼ inch microline, ¼ inch drip-line, ¼ inch TEE junctions, 4 inch sewer pipe (thin wall not schedule 40), a number of ½ inch pipe caps, and a number of 4 inch pipe caps. For tools you will need sturdy scissors, box cutter, optional irrigation multi-tool, X-acto saw, a hacksaw, a plastic hand shovel, and a cup of hot water, preferably in a thermos style travel cup. 

Note: when I use the phrase “a number of” that is the sprinkler head count.

For the Geo-location you will need an HID Prox reader, an old USB charger cable, a USB power pack, a number of HID Prox cards and a tube of E6000. I used one of the older Thinline II readers and matching 26 bit clamshell cards. Use the older 125 KHz prox cards as they have a longer read range. I have found the HID brand has the longest read range. Be sure the cards match the readers.

To help you, I have attached PartsList.pdf which list the parts and supplier links.

DON’T ORDER YOUR PARTS UNTIL COMPLETING STEP 1.

1)     Find your water cutoff and know how to use it – very important do not skip.

2)     Find your irrigation controller, turn on the zone you want to retrofit.

3)     Find all the sprinkler heads for that zone and mark them.

4)     Use the included ManifoldRecord.pdf as a guide make a list of the sprinkler heads. Give each head a temporary number or name for now, leave space for recording a five digit card number. Also note which plants to be served from that manifold. Below is an example record for a single manifold.

5)     Turn the irrigation controller off.

6)     Carefully dig around the sprinkler heads down to the supply pipe, expose the elbow or tee fitting. Your hole needs to be at least 6 to 8 inches in diameter. Be careful not to damage the pipes. I used a plastic garden trowel.

7)     Measure the depth of the supply pipe from the surface for each sprinkler and record.

8)     Carefully remove one sprinkler head and measure the supply pipe diameter, it should be ½ inch.

9)     Verify the riser for the sprinkler head is threaded and not glued into the elbow or tee fitting.

10)  Replace the sprinkler head.

11)  Using your list, subtract 2 ½ inches from the depth and record. That is the length of the nipple or riser you will need so that it can be buried.

12)  Using your list, add up all the depths of the supply line. That is how much 4” sewer pipe you will need. They come in ten-foot sticks.

13)  If your irrigation system doesn’t have a screen filter, strongly consider installing one.

14)  Now order your parts.

1)     Turn off the irrigation controller.

2)     Using your list of sprinkler heads, mark the 4-inch sewer pipe with the first length and label it with the sprinkler head number. This is your manifold shield.

3)     Use the hacksaw to cut the first pipe to length.

4)     Use the X-acto saw to cut notches in one end for the drip lines. They should be at least 3/8 inch wide and ½ to 1 inch deep. Use the box cutter to join the two saw cuts with a score. Break the tab off by flexing in and out.

5)     Remove the old sprinkler head and fit the appropriate riser (or nipple) to the elbow or tee fitting. Be sure to keep any dirt out of the pipe.

6)     Turn the irrigation controller on and turn the zone on to clear the pipe of debris.

7)     Turn the controller off after the water flows from the riser pipe.

8)     Cap the riser pipe with the ½ inch pipe cap.

9)     Test fit the manifold shield.

10)  Repeat from step 2 for all the sprinkler heads.

1)     Fill the tumbler with HOT water.

2)     Unroll a length of ¼ inch tube from the first plant supplied from the first drip manifold, add about 18 inches and cut with scissors.

3)     Mark BOTH ends with the next wire number.

4)     On your list, at plant for the manifold, make a note of the wire number.

5)     Dip the plant end of the tube into the tumbler for about 10 seconds to soften. See the video above for an example.

6)     Insert a TEE fitting into the tube. The multi-tool may help. Make sure to fully seat the tube past the barb and to the shoulder of the fitting. You may re-dip the pipe into the hot water. This softens the plastic again and will help fully seat the tube.

7)     Cut a length of the drip line long enough to encircle the plant’s drip line. Cut the line halfway between the drip holes.

8)     Dip one end of the drip line into the tumbler for about 10 seconds to soften.

9)     Push the drip line onto one of the other barbs on the TEE.

10)  Circle the plant with the drip line.

11)  Dip the free end into the tumbler for 10 seconds.

12)  Push the drip line onto the vacant barb on the TEE.

13)  Final product should look like this picture.

14)  Repeat for all the plants from step 2.

1)     Fill the tumbler with HOT water.

2)     Dip the manifold end of the ¼ inch tube into the tumbler for about 10 seconds to soften.

3)     Push the tube onto the manifold barb.

4)     Mark the top of the manifold with the wire number above the barb. Also note on your list the plant's tube number.

5)     Repeat from step 2 for all the plants served by this manifold.

6)     Turn off the manifold ports you won’t be using. 

7)     With all the plant tubes connected, wrap the tubes three or four times around the riser pipe, counterclockwise. This will unwind as you attach the manifold, then wind clockwise around riser pipe as you tighten. Winding and unwinding is one reason for the manifold shields.

8)     Remove the 1/2 inch pipe cap from the riser.

9)     Screw the manifold onto the riser. Try to keep the tubes tucked below the manifold valves.

10)  Repeat from step 2 for all the other manifolds.

1)     Glue one prox card into each pipe caps with the E6000. Make sure the numbers are visible.

2)     The clamshell cards just fit into the 4 inch pipe caps.

3)     Allow to dry overnight.

1)     Remove the pad from the extendable handle scrubber.

2)     Poke a hole in the middle of the pad and pass the reader wire through it.

3)     Pass the reader wire through the handle hole.

4)     Reattach the pad to the handle, pulling the slack from the reader wire.

5)     Secure the reader by tie-wrapping the reader wire to the handle.

1)     Carefully expose about two inches of the wires by carefully cutting the sheath away with the box cutter.

2)     Find the red wire from the reader. Please note some readers come with a red wire and a red wire with a stripe. Make sure you have the plain red wire. 

3)     Find the black wire from the reader.

4)     Remove end of the USB cable that does not fit the USB powerpak.

5)     Carefully expose about two inches of the wires by carefully cutting the sheath away with the box cutter.

6)     Find the red and black wires.

7)     Remove ½ inch of insulation from the red and black wires, four total counting the USB and reader.

8)     Twist the red wires together, twist the black wires together. Secure with tape.

9)     Plug the USB cable into the power supply, you should hear the reader do its sign-on salute.

10)  Wave a card past the reader, it should beep.

1)     Turn on the irrigation system. 

2)     Turn on the newly completed drip zone.

3)     Look at all the manifolds, make sure they are not leaking.

4)     Make sure the plant loops are dripping.

5)     Replace the manifold shield covers, making note of which card number is attached to which manifold.

6)     If all is good, then fill the space outside the manifold shield with dirt.

7)     Bury or hide the tubes from the manifolds to the plants.

8) Hide the manifold covers, I used a large rock to hide mine.

8)     Enjoy your new system knowing if you need to fix a drip loop, you will know where to start.