The system described here is the
product of an experiment ('speriment according to irish)
to build an effective, inexpensive, high tech MJ
machine. Irish and webfish are the primary proponents,
though much of the hydroponic community has contributed
in one way or another.
The basic design is a series of 4" pvc (schedule
40) tubes that are sealed on one end and drain back into
a central reservoir on the other. Plants are held in net
pots set into the tubes. Each plant is fed by a sprayer
set in the tops of the tubes. This placement
keeps the sprayers from becoming root clogged. The
system encourages root growth into the tubes and even
back through the drain and into the reservoir. The
system combines the benefits of aeroponic, ebb and flow,
NFT and deep water culture setups.
are fed through manifolds that run parallel to the 4"
tubes and branch off through either elbowed 1/2" pvc
(Irish) or 1/2" flexible tubing (Webfish). A 1450 gph
pump feeds webby's 4 tube system (pictured below), with
2 twin manifolds which emerge from the res and supply
each sprayer site.
When designing your
aerotubes, please keep in mind the following:
You want to be able to access all of your plants
during the grow. At a bare minimum, that means being
able to crawl under the system and go up between the
The recommended spacing between net pots
is 10 inches. That can be narrowed to 6-7 inches if you
are growing a sea of green, single cola plant.
Conversely, bushy, branchy plants demand up to 11 inches
The system will easily support a
SCroG application. Simply drill holes in the tubes for
the screen supports. Again, access is critical.
By using separate reservoirs, a grower can
propagate a perpetual garden or grow profoundly
The system may be
increased or reduced by simply adding or removing tubes
and either capping or disconnecting their manifolds.
The debate about
spray particle size in aero systems can be overlooked
with this system. The benefit of using the sprayers here
is not the way they feed the roots, but rather, how all
of that spraying and splashing aerates the nutrient
solution. Irish reports that you can actually see the
plants twitch as they grow during feeding time. The
systems use an average 500 ppm nutrient mix fed in five
minute on cycles every fifteen minutes. Webby says that
he never goes over 800 ppm.
Note that the sealed ends of the 4" pvc are
elevated to promoted drainage. Also, the two outer most
4" pvc tubes are elevated above the inner 4" tubes for
the same purpose. Further, the roots tend to extend from
the net pots and down hill until finally they grow to
the reserviour. Webby warns that the plants can bust a
3" net pot. Make sure that you have some way of keeping
growrocks out of your pump!
Check out this image
of Irish's drain tubes.
Each plant site is 11" on center and
offset 5" from the plant site accross from it in the
adjoining tube. Irish devised this integrated method for
supporting plants during heavy flowering (with yields of
better than 3 oz's per plant, we can see that necessity
is truly yo mama of invention).
SPRAYER FEED LINE ALTERNATIVE
satisfied with the relative simplicity of Webby's
design, Irish devised the following method for
constructing his sprayers.
Tools used here were:
(1) 9/64" drill
(1) 10-32 threaded tap
rainbird full circle micro spray jet #360JET010
1/2" female pvc threaded cap with "nut" molded to the
(1) 1/2" pvc elbow (slip thread x 1/2" male
(1) 1/2" pvc slip cross
(1) small stick
of pvc 1/2"
(1) pvc cutter
(1) 1 1/8" hole saw
connections should be sealed with the pvc glue to
prevent leakage. The o-rings for the sprinklers can be
bought in the same irrigation aisle.
- attach fem cap to male elbow
- drill hole with the 9/64" drill bit into the cap
(here you may do two as done, or one would probably
- tap the hole(s) you just drilled with the 10-32
tap, this is the thread size of the sprinkler
- insert sprinkler
- take the hole saw and drill the 1 1/8" hole where
you have decided it should go. Web's suggestion is to
place one hole on each side of the 3" netcup holes.
- insert cap and sprinklers into the hole, should
fit snug, you can purchase an O-ring to seal the fit
better, but it should be okay
The pvc cross is used to make a
connection to the main manifold. One extension from each
side, leading to the "feeder holes"