Tuesday, June 20, 2017

Trickle Irrigation

Putting trickle irrigation into the "serious" orchard has been on my bucket list.
$40 for 500 feet of poly tubing.
An additional $60 bucks for assorted doo-dads.
$25 of the sixty dollars went into the filter and hardware to adapt it to incoming garden hose (left side) and two 1/2" poly outlets (right side).
Then it was a matter of stretching poly pipe, putting flushable end-pieces on the dead ends and pressing in emitters.  I found it easier to insert the emitters when the line was under pressure. 
This is what the flow out of a two gallon-per-hour emitter looks like.   Now, instead holding a hose over each tree for a minute, I can hook the hose to the filter and run it for three hours which will free me up to do other things.
These are a "pressure compensating design".  Presumably, the white disk acts like the diaphragm in a pressure regulator and interacts with the labyrinth molded into the bottom of the red cap to modulate flow from 10psi-to-45psi.

Second vertical line is 15psi.  Sixth vertical line is 45psi.  Data from HERE
It took me about 90 minutes to run 450 feet of poly pipe, assemble hardware and to insert fifty emitters.  The hose from the house runs about 300 gallons per hour when there is no back-pressure.  Fifty emitters should pull about 100 gallons per hour.  I will add a few more as I fill in "holes" in the planting.

I am pretty happy about how it went.  I still have 40 emitters left and am thinking about doing the same for the pears planted out front.  I will be able to save about $20 if I move the filter assembly to whichever area I am irrigating.

Bill of Material
500 feet, 1/2" black poly irrigation tubing (about $40)
90, Rainbird, 2 gallon/hour emitters (3 packages of 30 at $7.11 each)
One Rainbird emitter installation tool (about $5)
One package of two, 1/2" compression Tee fittings ($3.99 for two)
One 3/4" "hose" female to 3/4" NPF female fitting, brass ($8)
One 200 mesh filter, 3/4" NPF male both ends ($10)
One 3/4" NPF female-to-3/4" "hose" male fitting ($1.55)
One 3/4" "hose" female, to two 1/2" female compression fittings ($5)
Four Universal 1/2" flush caps ($3.59 each)


  1. Depending on soil, 2g/hr. will only wet a small area. Did you put 3 emitters per tree? You can use short lengths of spaghetti tubing from the emitters to the other side of the tree. I don't use self flushing caps as I like to get the pipe really clean once in awhile - especially after installation. I usually just bend the end of the pipe over itself and either tape it tight or slip a sleeve (a 4" section of 1 1/2" pvc pipe over the bend. Works well.

    1. The soil is nominally Marlette Loam (https://soilseries.sc.egov.usda.gov/OSD_Docs/M/MARLETTE.html).

      My biggest concern, at this point, is sizing up my smaller trees and growing their canopies to fill their allotted space. I positioned the single emitter about 12 inches from the trunk.

      The current literature seems to favor frequent waterings and to not use the buffering capacity of the soil. I don't understand why.

      I agree that the moistened area will be narrow and deep. Since it will not move, the trees (supposedly) will fill the volume with many feeder roots.

      Thanks for writing.