Hydroponic Systems

There are different ways to bring water to the plants. The main types of hydroponic growing systems are:
• Drip Irrigation System
• Wick System
• Water Culture System
• Ebb and Flow System
• Nutrient Film Technique System
• Aeroponic System
• Aquaponics 
• Ultraponic (Fogponic) System 

Drip System

This is very widely used hydroponic system due to its simple setup, high efficiency and low cost. It is popular solution for everything from backyard or garage vegetable gardens to large-scale industrial farms that want to save money and resources.

The basic premise is that nutrient solution is periodically pumped out of the reservoir by a tubing, usually 1 inch, which is divided into ½ inch lateral lines that run directly alongside the plants. These lateral lines contain a dripper for each plant, which is placed directly at the plant base and provides a controlled flow of nutrient solution directly to the roots. Then the solution is collected back in the reservoir to be reused again. A timer controls a submersed pump. The cycle repeats usually 4 to 6 times (every 3, 4 hours in the light period and once at the middle of the dark period) a day for about 15 minutes.

There are a lot of different types of drip irrigated hydroponic system depending of the number of plants, space available, but the principle is always the same – reservoir – tubing – dripper – roots – reservoir and… repeat. The using of timer reduces the man work to a minimum, which is periodical check and adjust (if needed) the PH level of the solution and also the solution should be changed every 2-3 weeks or when the plant enters the next phase of his life and need a different solution mixture.

Wick system

The wick system is very simple form of hydroponic kits. This is a passive system – once set it works by itself. The nutrient solution does not move and riches the roots from the reservoir through wicks. The growing media used in the wick system is usually a mixture of various growing media like rockwool, perlite, coconut fiber – in order to increase to the utmost their capillary capacity and keep the plants up-right and sturdy. Wick systems use woven nylon rope to draw water up to the planting medium. The water is drawn up automatically as it is needed to maintain a certain moisture level. Most planting mixes maintain a moisture level sufficient for plant roots to draw upon. The soil should not get soggy because it maintains air space between the particles, allowing for proper drainage.

It’s a very easy to set and very compact system and is very usefull in small home gardens for growing in small spaces. The upside is that you can’t overwater a plant in a wick system, protecting new growers from the most common newbie mistake. They also will water plants when the grower forgets- as long as the res is kept full.
This system’s biggest disadvantage comes with large plants which need large amounts of water which the wicks are unable to supply. Another downside is that wicks don’t move as much oxygenated nute solution across the rootmass as a recirculating system does and as such can’t be as productive nor as fast as a recirculating hydro system. That’s why the air pump is a good idea.

Deep Water Culture System (DWC)

DWC is a system of growing plants in aerated water.

The plants are suspended on a floating platform (usually styrofoam) and the root system of a plant is immersed in water (nutrient solution) with a bubbling aerator keeping the roots oxygenated. Aquarium or another trasparent container can be used, which make the system very popular for classrooms because the roots of the plants are visible hanging below the floating platform.
   

  Deep Water System is a good choice for growing herbs (parsley, coriander, basil, etc), lettuce and leafy vegetables.

The biggest disadvantage of this kind of system is that it doesn’t work well with large plants or with long-term plants.

Ebb and Flow System

...also known as Flood and Drain System

E&F is may be the most popular hydroponic system due to its simplicity and versatility. The plant is grown in the medium where it develops its roots, and, at intervals nutrient solution is pumped in from a reservoir, flooding the table or bucket; when the pump turns off, the nutrient solution is drained back in the reservoir.

A timer is attached to the pump and is used to set the frequency of the flood and drain periods, which is 3 to 5 times a day (depending of the medium used, the size and type of plants, temperature and humidity) for about 5-10 minutes each . Between the periodic flooding, the roots are exposed to more oxygen. This increased exposure to oxygen increases the plant’s use of the available nutrients, and therefore, promotes faster growth.

In the Flood and Drain technique the plants are placed in a large container called grow bed, which contains the growing medium (rockwool cubes, perlite,  hydroton or some other medium). The container should have two holes – inlet – where the water tubes bring the solution, and outlet, which flows the water back in the reservoir. The outlet has an overflow set at a predefined hight, which will allow the water level to reach a level that will cover the entire roots of the plants.

Nutrient Film (The Jetfilm) Technique System (NFT)

N.F.T. systems have a constant flow of nutrient solution. It was developed as a way of giving plants’ roots constant access to water, nutrients and the all-important oxygen! The nutrient solution is pumped into the growing tray (usually a tube) in a very shallow stream and flows over the roots of the plants, and then goes back into the reservoir. There’s little or no growing media used in NFT systems.

Anything can be grown with this technique – from leafy vegetables and herbs to bigger plants like tomatoes and cucumbers.
The main disadvantage ot the NFT is an eventual pump failures or power outages, because as no growing medium is used the roots dry out very rapidly when the flow of nutrient solution is interrupted.


Aeroponic System

Aeroponics is one of the most high tech growing systems. It is very expensive and complicated technique and is usually used by professional growers. Requires heavy maintenance and great attention to detail, close monitoring and have a total reliance on constant electricity. There’s no growing media used. The roots hang in the air and are periodically sprayed with a nutrient solution, usually every few minutes. The timer that controls the pump should run for a few seconds every 2-3 minutes.

Air cultures optimize access to air for successful plant growth. Aeroponics is a technological leap forward from traditional hydroponics. It uses both water and air to produce more colorful, better tasting, better smelling, and incredibly nutritious fruits and vegetables.

Aquaponics 

Aquaponics is the method of growing crops and fish together in a re-circulating system. It is a system that combines conventional aquaculture, (raising aquatic animals in tanks), with hydroponics in a symbiotic environment. The waste produced by farmed fish or other aquatic creatures supplies the nutrients for the plants.

Plants are grown as in hydroponics systems, with their roots immersed in the nutrient-rich effluent water. This enables them to filter out the ammonia that is toxic to the aquatic animals, or its metabolites. After the water has passed through the hydroponic subsystem, it is cleaned and oxygenated, and can return to the aquaculture vessels. This cycle is continuous.

The hydroponic techniques usually used is Deep Water Culture or Nutrient Film Technique, but all the hydroponic systems are suitable in Aquaponics. 

Most green leaf vegetables grow well in the aquaponic system - varieties of chinese cabbage, lettuce, basil, roses, tomatoes, bell peppers are most common. Other vegetables that grow well in an aquaponic system include beans, peas, watercress, radishes, strawberries, melons, onions, and herbs.

Freshwater fish are the most common aquatic animal raised using aquaponics, although freshwater crayfish and prawns are also sometimes used.  Tilapia are the most popular fish for home and commercial projects that are intended to raise edible fish. Silver Perch, catfish, Jade perch and Barramundi are also used. Goldfish  can be used if do not want to have edible fish.

Aquaponic systems do not discharge or exchange water. The systems rely on the natural relationship between the aquatic animals and the plants to maintain the environment. Water is only added to replace water loss from absorption by the plants or evaporation into the air.

Ultraponic (Fogponic) System

Ultraponics or Fogponics is one of the most recent techniques. It is an advanced form of aeroponics (the same system as aeroponics except fogponics utilize a 5-30 µm mist within the rooting chamber, while Aeroponics uses a 50-80 micron droplet size) which uses water in a vaporised form to transfer nutrients and oxygen to the plant roots.

  The nutrient solution is vaporized on the roots with an ultrasonic atomizer. The ultrasonic atomizer is an electrical device which transforms the the water  into a mist of very fine droplets (about 5 microns).  Plants best absorb particles from the 1-25 µm range, the smaller particulate size means faster absorption. These droplets are so fine that they can be absorbed immediately through the pores of the roots. The mist circulates in the container in which the roots are housed using a fan and is ideal for plants, adding healthy moisture to any dry environment.

The Mist maker unit uses no chemicals, no dry ice and no heat.- it’s a cool safe mist that just uses normal water.

 This technique is particularly suitable for the horticultural industry.