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Theoretically
there are six types of
hydroponics
systems. Of course
hydroponics systems come in too many variations for anybody to
be able to index them all, but essentially any of those system
variations can be defined as a combination between the primary
hydroponics systems. Let's have a look at their main features
and see what they consist of.
The Water Culture System is the simplest of all active hydroponics
systems. The platform that holds the plants is usually made of Styrofoam and
floats directly on the nutrient solution. An air pump supplies air
to the air stone that bubbles the nutrient solution and supplies
oxygen to the roots of the plants.
Water culture is the system of choice for growing leaf lettuce,
which are fast growing water loving plants, making them an ideal
choice for this type of hydroponics system. Very few plants other
than lettuce will do well in this type of system. This type of
hydroponics system is great for the classroom and is popular with
teachers.
A very inexpensive system can be made out of an old aquarium or
other water tight container. The biggest draw back of this kind of
system is that it doesn’t work well with large plants or with
long-term plants.
The Ebb and Flow System works by temporarily flooding the grow tray with
nutrient solution and then draining the solution back into the
reservoir.
This action is normally done with a submerged pump that is
connected to a timer. When the timer turns the pump on nutrient
solution is pumped into the grow tray. When the timer shuts the pump
off the nutrient solution flows back into the reservoir.
The Timer is set to come on several times a day, depending on the
size and type of plants, temperature and humidity and the type of
growing medium used. The Ebb and Flow is a versatile system that can
be used with a variety of growing mediums. The entire grow tray can
be filled with Grow Rocks, gravel or granular Rockwool.
Many people like to use individual pots filled with growing
medium, this makes it easier to move plants around or even move them
in or out of the system. The main disadvantage of this type of
system is that with some types of growing medium (Gravel, Growrocks,
Perlite), there is a vulnerability to power outages as well as pump
and timer failures.
The roots can dry out quickly when the watering cycles are
interrupted. This problem can be relieved somewhat by using growing
media that retains more water (Rockwool, Vermiculite, coconut fiber
or a good soiless mix like Pro-mix or Faffard’s)
The Wick System is by far the simplest type of hydroponics system. This is a passive system, which means there are no moving parts.
The nutrient solution is drawn into the growing medium from the
reservoir with a wick. This system can use a variety of growing
medium. Perlite, Vermiculite, Pro-Mix and Coconut Fiber are among
the most popular.
The biggest draw back of this system is that plants that are
large or use large amounts of water may use up the nutrient solution
faster than the wick(s) can supply it.
Drip Systems are probably the most widely used type of hydroponic
system in the world. Operation is simple, a timer controls a submersed pump. The timer
turns the pump on and nutrient solution is dripped onto the base of
each plant by a small drip line.
In a Recovery Drip System the excess nutrient solution that runs
off is collected back in the reservoir for re-use. The Non-Recovery
System does not collect the run off.
A recovery system uses nutrient solution a bit more efficiently,
as excess solution is reused, this also allows for the use of a more
inexpensive timer because a recovery
 system doesn’t require precise
control of the watering cycles. The non-recovery system needs to
have a more precise timer so that watering cycles can be adjusted to
insure that the plants get enough nutrient solution and the runoff
is kept to a minimum.
The non-recovery system requires less maintenance due to the fact
that the excess nutrient solution isn’t recycled back into the
reservoir, so the nutrient strength and pH of the reservoir will not
vary. This means that you can fill the reservoir with pH adjusted
nutrient solution and then forget it until you need to mix more. A
recovery system can have large shifts in the pH and nutrient
strength levels that require periodic checking and adjusting.
The Aeroponic System is probably the most high-tech type of hydroponics gardening. Like the N.F.T. system the growing
medium is primarily air. The roots hang in the air and are misted
with nutrient solution.
The mistings are usually done every few minutes. Because the
roots are exposed to the air like the N.F.T. system, the roots will
dry out rapidly if the misting cycles are interrupted.
A timer controls the nutrient pump much like other types of
hydroponic systems, except the aeroponic system needs a short cycle
timer that runs the pump for a few seconds every couple of minutes.
N.F.T. is the kind of hydroponics system most people think of when
they think about hydroponics. N.F.T. systems have a constant flow of
nutrient solution so no timer required for the submersible pump. The nutrient solution is pumped into the growing tray (usually a
tube) and flows over the roots of the plants, and then drains back
into the reservoir.
 There is usually no growing medium used other than air, which
saves the expense of replacing the growing medium after every crop.
Normally the plant is supported in a small plastic basket with the
roots dangling into the nutrient solution.
N.F.T. systems are very susceptible to power outages and pump
failures. The roots dry out very rapidly when the flow of nutrient
solution is interrupted.
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