The aeroponic system is probably the most high-tech type of
hydroponic gardening. Like the N.F.T. system above 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.
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 Wick system is by far the simplest type of hydroponicsystem. This is a passive system, which means there are no moving parts. Thenutrient solution is drawn into the growing medium from the reservoir with awick. Free plans for a simple wick system are available (click here for plans).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 arelarge or use large amounts of water may use up the nutrient solution fasterthan the wick(s) can supply it.WATER CULTUREThe water culture system is the simplest of all activehydroponic systems. The platform that holds the plants is usually made ofStyrofoam and floats directly on the nutrient solution. An air pump suppliesair to the air stone that bubbles the nutrient solution and supplies oxygen tothe 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 forthis type of hydroponic system. Very few plants other than lettuce will do wellin this type of system.This type of hydroponic system is great for the classroom and ispopular with teachers. A very inexpensive system can be made out of an oldaquarium or other water tight container. The biggest draw back of this kind ofsystem is that it doesn't work well with large plants or with long-term plants.