Typical Dirt Gardening:
All plant leaves need light, oxygen and carbon dioxide. Plant root systems require water, nutrients and oxygen. When plants are grown normally (in soil) water takes nutrients from the soil and carries them to the plant roots. The water and nutrients are taken up by the roots to feed plant growth. Soil drainage then allows water to be replaced by air in the gaps between soil grains. This supplies the roots with oxygen.
Hydroponic Gardening:
In hydroponic plant systems, you dissolve the nutrients in water. Soil is replaced with a "growing medium" - a soil substitute - that holds the roots and supplies them with water, nutrients and oxygen. You can deliver the nutrient solution a couple of ways: You can drip feed it to each plant, or you can flood the root chamber, then drain it out. These methods require a pump and timer to circulate the nutrients through the roots. You can also grow the plant roots in the air by spraying them with a fine mist of nutrient solution, or grow them by aerating the solution under each root mass with an air pump.
Actually, six basic types of hydroponic systems make up the basis of all hydroponic gardening.
Wick
Water Culture
Ebb and Flow (or Flood & Drain)
Drip
Nutrient Film Technique (N.F.T)
Aeroponic
Let's take a look at these 6 basic hydroponic plant systems:
Wick
The wick system is the simplest and easiest to build of all the systems available. It has no moving parts, and requires no electrical energy source or special attention.
The nutrient solution is drawn into the grow bed from the nutrient reservoir through the capillary action of wick material and absorbent grow media. When plants get very large, they may use nutrients faster than the wicks can supply them.
Water Culture
The water culture is another very simple hydroponic system. Plants grow with the roots suspended in the nutrient solution. The structure that holds the plants is usually made of styrofoam and floats directly on the nutrient solution. An air pump delivers the nutrient solution and oxygen to the plant roots. The main disadvantage of a water culture system is that it doesn't work well with large plants or with long-term plants.
Ebb and Flow (or Flood and Drain)
The ebb and flow hydroponic system works by temporarily flooding the grow tray with nutrient solution and then draining the solution back into a reservoir. Usually the pump is submerged and is connected to a timer.
The ebb and flow system can be used with a variety of growing media. The entire grow tray can be filled with grow rocks, gravel or granular rock wool. You can use individual pots filled with growing medium. This makes it easy to move plants around or even move them in or out of the system.
Drip Systems (Recovery and Non-Recovery)
Drip systems are probably the most widely used type of hydroponic plant system. Basically, a timer controlled pump delivers nutrient solution to drippers located at the base of each plant.
In a Recovery Drip System the excess solution runs off and returns to the tank for re-use. A Non-Recovery System does not collect the run-off which therefore goes to waste.
Nutrient Film Technique - "N.F.T."
This is another very popular hydroponic system. A constant flow of nutrient solution pumped from a tank flows over the roots of the plants in a tube or tray and then returns to the tank.
The growing medium is mostly air, plus whatever medium was used to grow the plant from a seed or cutting (usually rock wool or perlite.)
Aeroponic
The aeroponic system is probably the most high-tech type of hydroponic gardening. The growing medium is primarily air. The roots hang in the air and are misted every few minutes with nutrient solution. 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.
Many growers prefer hydroponic plant systems and believe them to be a far more efficient way to provide water and nutrients to their plants. Since food and water go directly to the roots, the plant is able to spend more energy growing above the surface, producing more vegetation, larger fruit, flowers and vegetables.
Copyright 2006 Robert Mosse
