1. Introduction to Hydroponics
What is Hydroponics ?

2. Hydroponics is the technique of growing plants without soil.
The word Hydroponics comes from the Greek “Hydro” meaning water and “Ponos” meaning labor
Hydroponic crops rely on a nutrient solution to supply all the water and mineral requirements of the plant.
Hydroponic nutrient solutions are made up of “plant Food” fertilizers dissolved into water at correct strengths- all essential nutrients required by the crop are supplied via this solution.

3. Why use Hydroponics ? The main advantages of Hydroponics are:
Optimal plant nutrition provides all the mineral elements required for maximum growth and product quality
No weeds or soil borne pests and diseases. Less watering required compared to irrigated soil cropping more efficient use of water.

4. Ideal root zone conditions of oxygenation and moisture levels
Suited to greenhouse and protected environment cropping. Hydroponics can be carried out where the soil is unsuited for cropping or where no soil exists> (i.e. roof tops, indoor and factory hydroponics)
Significantly higher yields and control over factors, such as flavor and shelf life.

5. A Brief history of Hydroponics ?
Hydroponic dates back to the hanging Gardens of Babylon built in 600B.C.
The Aztec Indians had a system of growing crops on rafts anchored in lake waters
The Intha tribe still use floating gardens to cultivate crops today.
Commercial development began in Europe in 1699 when John Woodward found that plants could be grown in a solution of soil and water. Over the next 200 years, studies into the nutrient requirements of plants allowed scientist to grow plants of solutions made of mineral salts. In 1930 the first commercial hydroponic facility was built by US scientist William Gericke and during WWII the American forces in the pacific grew vegetables hydroponically. In 1970’s the first Nutrient Film Technique NFT was developed by Dr. Allen Cooper in the United Kingdom UK.

6. Hydroponics Systems
The most common method of Hydroponic systems are:
A solution culture where the plant roots are immersed in water containing dissolved nutrients.
Solution culture systems include; Nutrient Film Technique (NFT) Aeroponics, deep flow systems Raft pond or raceway systems
The most common method of Hydroponic systems are: Solution culture where the plant roots are immersed in water containing dissolved nutrients and Media culture where a non-soli substrate is used to support the plants with water and dissolved nutrients are applied on a regular basis.

7. Hydroponics Systems Solution Culture Systems
No solid growing medium is used
Plant roots a bathed with a flowing or static nutrient solution
The nutrient solution must supply the plants requirements for water, oxygen (dissolved oxygen contained in the solution) and nutrient elements.
The most common solution culture system used in commercial crop production is NFT (Nutrient Film Technique) and pond or raft systems (also called raceway systems). Not all plants are suited for solution culture systems. Solution culture systems are most commonly used for smaller plants such as lettuce, herbs and salad greens..

8. Solution Culture Systems
The solution – is heated or chilled (depending on climate)
Boost production level
Boost uptake rate of nutrients
Nutrient solution - aerated to increase the level of dissolved oxygen required by the root system
The solution may be heated or chilled depending on climate to boost production levels and the uptake rate of nutrients. Nutrient solution are also aerated to increase the level of dissolved oxygen required by the root system

9. Nutrient Film Technique (NFT)
NFT-most widely used method of solution culture by commercial growers.
Nutrient flows in a thin film over the base of the growing channels which supports the plants.
This thin film of nutrients ensures the plant roots have access to nutrients, water and oxygen via the moist air above the nutrient solution
NFT or Nutrient Film Technique is the most popular and widely used method of solution culture by commercial growers. The principal of NFT is that the nutrient flows in a thin film ( a fraction of an inch deep) over the base of the growing channels which supports the plants. This thin film of nutrients ensures the plant roots have access to nutrients, water and oxygen via the moist air above the nutrient solution.

10. The nutrient solution circulates around the system via a pump- flowing into the growing channels at one end and out of the other, back to the main nutrient tank
The nutrient solution composition is adjusted back at the tank to maintain the correct concentration (EC) and pH for plant growth
The NFT nutrient solution circulates around the system via a pump- flowing into the growing channels at one end and out of the other, back to the main nutrient tank. The nutrient solution composition is adjusted back at the tank to maintain the correct concentration (EC) and pH for plant growth. Water and nutrients are added to the solution either manually or automatically as required.
In the early days of NFT systems before the range of plastic products we have now, the channels or gullies were constructed of either concrete or timber and painted/lined with waterproof material through which the nutrients would flow.
Modern NFT systems are now made with a range of channel sizes and shapes to suit different crops and applications.
Many NFT systems can be purchased as a complete growing system that comes with pumps, growing channels, nutrient tanks, plant support tubes/pots and all irrigation components.
Water and nutrients are added to the solution either manually or automatically

11. Advantages to using an NFT System:
NFT systems are Typically constructed on benches or at suitable working height (No back strain)
NFT recirculates the nutrient solution, hence water and fertilizer are efficiently applied if run correctly
The solution is measured and adjusted at the nutrient tank- the (EC) of the solution in the tank is exactly what the plant roots experience in the system (unlike substrate-based systems)
The solution can be chilled or warmed, depending on the climate, to boost the growth and will directly cool/warm the root system
Roots can be examined in the channels with ease.

12. Solution Culture Systems
Deep Flow Systems
Uses a deeper flow of solution than NFT
Larger plants, such as tomatoes can be grown in a deep flow system
Oxygenation of the solution is vital to the success of deep flow systems as the submerged roots are dependent on oxygen dissolved into the nutrient solution.
As much as one foot in depth depending on the crop being grown