Maximum Yield Australia/New Zealand May/June 2019 | Page 57

Ebb and Flow Systems
Grow Tray
Reservoir
Nutrient Solution
Nutrient Pump
Air Pump
Air Stone
A Nutrient Film Technique system utilises a constant gentle flow
of nutrient solution over the bottom of the plant root systems. This
allows roots to breathe air and take in nutrients at the same time.
Ample oxygenation of the nutrient solution is neccessary to ensure
successful root respiration.
Bell Syphon
Grow Tray
Reservoir
Timer
Nutrient Solution
Nutrient Pump
Air Pump
Air Stone
An Ebb and Flow system involves a timed flooding of the grow tray
with nutrient solution in cycles. A Bell Syphon allows the grow tray to
drain automatically once full. This allows roots to breathe air and take
in nutrients in turn, while minimising energy input. Oxygenation of the
solution is not neccessary but can be beneficial.
These PVC canals are then mounted on a wood frame which
positions them a few feet off the ground, and at a slight
angle. After that, place a rectangular shaped reservoir
(that mirrors the garden size) underneath the PVC/wood
frame. The water pump will pump the nutrient-rich water
solution through the PVC pipe and through the root zone of
the plants, which will then filter back to the reservoir by the
angled PVC and gravity. While the water can directly drain
from the PVC into the reservoir in a sort of waterfall, many
prefer to rig a hose that uses gravity to feed it back to the
holding tank. Finally, the air pump and air stone are used
to aerate the recirculating reservoir water.
Ebb and flow hydroponic systems are defined by the large,
rectangular “hydro tables” seen in many indoor grows.
For small-scale, home-based growing, these systems are
a safe bet as they have less parts than NFT. To illustrate,
ebb and flow systems house all the plants on a single table
(or several tables) in a grid formation, essentially sharing
the water and garden space. This method is characterised
by the periodic flooding of the hydro table in which grow
mediums and plants rest. Ebb and flow is set apart from
NFT by the fact that with this process, the grow medium
and plant roots are almost entirely submerged in nutrient
water in static flooding cycles, unlike the continuous film
flow seen with NFT. For purposes here, we will be looking
into rearticulating ebb and flow systems.
To design an ebb and flow system of your own, many of
the NFT system principles are still at play, with some larger
emphases on efficient timing and accurate flooding. With this
notion in mind, the constituent part of an ebb and flow system
generally mirrors those of an NFT system, with a hydro table
replacing the canals, plus reservoir, air pump, tubing, air
stone, water pump, timer, table, and grow medium.
The most basic, as well as affordable, infrastructure for
a DIY ebb and flow garden begins with two symmetrical
plastic containers, with one being a good deal deeper than
the other. The crux of the setup is the deeper container will
act as the reservoir while simultaneously supporting the
upper shallow container, which houses the grow medium
and plants. Using a drill, two holes should be drilled into
the bottom of the shallow container — one will receive
nutrient-rich water and one will expel it. Moving forward,
you will connect the water pump to a plastic hose that
penetrates the water entry portal to fill the shallow grow
container. This will be your intake irrigation hose. Next,
another plastic hose will be set to penetrate the bottom
of the shallow container as the water outtake portal. This
water expulsion tube should be lined with a screen and
penetrate about two-inches into the grow medium off the
base of the flood container; this will act as an overflow when
irrigation water gets to the ideal point. Interestingly, when
the pump and water shut off, excess water is sucked back
into the main holding reservoir with a siphoning effect,
effectively letting the grow medium and root zone dry out.
The water outtake system should ensure that medium is
adequately drained after each flood, otherwise there will be
a plethora of overwatering issues. Timing is essential with
ebb and flow systems, and an accurate timer must be imple-
mented to allow for precision in flooding, as most plants like
their root systems to at least partially dry out between irri-
gation intervals. This rhythm can only be achieved by trial
and error, so a watchful eye will be helpful in getting your
ebb and flow setup off the ground.
Homemade hydroponic systems are not only affordable,
they can be quite educational. As many experienced
horticulturists know, the only way to truly master a grow
technique is to understand every facet of the system. While
DIY hydro systems are likely not dependable enough to
employ on a commercial scale, they can be extremely
helpful for the novice grower interested in understanding
the ins and outs of hydroponics. Whether it be with NFT or
ebb and flow, building your own hydroponic system is a fun
and practical way to begin amassing a knowledge base on
modern gardening techniques.
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