Drip Irrigation Considerations
this information as a PDF
Before setting up a T-tape or Emitter System figure
out how much water is available for your plan. Calculate the rate
of flow of water your well or city system provides by measuring
the time needed to fill a 1 gallon pail from your spigot. Divide
3600 by the number of seconds it takes: that will be the number
of gallons per hour. Don’t plan to use more the 80% of that
number. If it took 15 seconds to fill the pail, the rate of flow
is 240 gph and your layout should not require more than 192 gallons
Next, draw a layout of your garden or the area
you wish to irrigate:
Click the image for a larger view.
To plan your T-tape layout, draw the lines you
plan to lay and calculate the total length of line you are going
to use. Next, determine how much water this will require. The low-flow
T-tape we supply uses 20 gph per 100' at 8 psi, so a layout using
1000' of T-tape would use 200 gallons of water each hour it is running.
If your plan calls for more water than you can
supply, you can use T-connectors and shut-off valves in the mainline
to direct the water to different areas of the garden. If you are
going to divide your garden to water at different times, consider
planning your rows so that plants with similar watering requirements
are in the same section.
If your garden is on a slope, plan to lay the
mainline at the top and have the drip tape lines run downhill. Different
soil types will require different amounts of water.
Using emitters and sprinklers:
Lay out sections of mainline along your nursery rows, using the
couplers to join sections. For young plants and trees, one or two
emitters per plant are sufficient, larger trees or shrubs will require
more emitters, you can get 1/4" line and barb connectors to
lay the emitters along the drip line of the plants for better irrigation.
To assemble your drip irrigation:
Attach the vacuum breaker directly to the spigot. If you are using
a Y-spigot, attach the breaker to one of the outlets.
Attach the filter to the vacuum breaker. Attach the pressure regulator
to the filter. (The cap at the bottom of the filter is for flushing
out the filter.)
Attach a garden hose or the smart-loc hose-beginning to the pressure
Click the image for a larger view.
To use Smart-Loc fittings:
Turn the collar clockwise until it meets the body of the fitting
to open it, put the tubing over the barb and slide it as far as
it will go toward the body of the fitting, turn the collar clockwise
over the tubing until the collar is tight. Hand tight should be
sufficient. Tug to test the connection. (If the connection appears
to leak, try tightening it further with a pair of pliers.) T-tape
is fitted to its connectors in the same manner.
Lay out your T-tape along the garden beds according
to your plan. Lay the mainline out and cut to desired length, insert
the hose end with cap. Use the punch to make holes in the mainline
where the T-tape will connect. Drive the punch firmly into the mainline
until you hear a pop. It helps to hold the mainline on either side
to stiffen it and prevent it from collapsing.
Insert the barb end of the T-tape fitting into
the hole and slide the tape over the larger barb and tighten as
above. Repeat for each T-tape line. (If you’ve punched a hole
in the wrong location, use a goof plug to repair the hole and punch
a new one.)
Once the mainline is laid out and the holes punched,
you can use the U-shaped hold-downs to keep the system in place.
Before closing off the T-tape ends, run water
through the system to flush it out. Open the end of the mainline
so it will flush as well.
To close the ends of the T-tape, slide the sleeve
end over the tape so that the wider opening is toward the end of
the T-tape, fold the end of the T-tape over three times and slide
the sleeve-end over the folds. It will wedge tight and seal the
For emitters follow the steps above to install
the filter and mainline beginning. Lay the mainline along the nursery
beds and punch holes for emitters where needed. Pop in the emitters
and flush the line.
If the area you are irrigating is far from the
spigot, you might want to make the connection between the mainline
and the spigot with a garden hose or a separate piece of mainline
fitted out with hose beginnings and ends so that it can be taken
up if you want to mow or move things back and forth.
You can leave irrigation in the garden over the
winter. If you plan to do that, thoroughly purge the lines of water.
T-tape will last two-to-five years if left outside and up to seven
years if taken in at the end of each season. Mainline tubing will
last up to eight years exposed to sunlight, longer if covered.
DRIP IRRIGATION SCHEMATIC
Click the image for
a larger view.