What is Hydroponics?
Hydroponics is the method of growing plants without soil (i.e., soil less cultivation.) In this technique the root absorbs balanced nutrient which is dissolved in the water that meets all the plant development requirements. There are many aggregates and medias which support the plant to grow.
Why grow hydroponically?
Carbon dioxide + Water = Glucose + Oxygen
6CO2 + 6H2O= C6H12O6 + 6CO2
We can get many times greater yields than the conventional method. With smaller roots we can grow more plants in the same area and greater yields. Many pests are carried in soil, so doing without it generally gives you a more hygienic growing system with fewer problems of disease.
Nutrient Film Technique (NFT)
This is a method that has probably been around longer than any other hydroponics methods. You will hear sales people at the grow stores, say it is the “Old School Method.” This method is also popular among commercial growers because of its versatility and aggressiveness. NFT consists of a long grow chamber such as PVC pipe or channel. At evenly spaced intervals along the pipe, there are holes containing either collars, baskets, or in some cases, grow media in which plants are held. The roots of the plant hang down in the hole and a shallow stream, or “film” of water is run across the root tips.
In a simple NFT hydroponic system the nutrient is stored in a tank (A) and then pumped along narrow tube by a submerged flow pump (B). The systems is sized to deliver typically 2-3 litres per minute of nutrient 24 hours per day into the growing channel (C). This creates a thin film of nutrient along the bottom of the angled grow channel which can then be absorbed by the plant roots. Excess nutrient is then collected and returned to the nutrient tank (E).
NFT relies on a continuously running pump to deliver a low but continuous flow of nutrient over the plant roots. The pump used must be designed for continuous operation.
As with all re-circulating systems, the nutrient concentration will fall over time as the plants absorb the dissolved minerals. The Electrical Conductivity (EC) of the solution will need to be maintained by adding additional nutrients and the whole solution will also need to be changed periodically.
Advantage of NFT
- Lower water and nutrient consumption.
- Avoids the supply, disposal and cost problems associated with media based systems.
- The absence of medium makes it easy to inspect roots for signs of disease, feed adequacy, etc.
- Environmentally friendly – minimal potential for localised groundwater contamination.
- Relatively easy to disinfect roots and hardware compared to other system types.
- Regular feeding (and associated flushing) prevents localised salt build-up in the root zone and maintains uniform root zone pH and conductivity.
- Constant water movement keeps water from going stagnant.
- The cost of building a NFT system is low.
Deep Water Culture (DWC)
Deep water culture (DWC) is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich oxygenated water. This system is typically comprised of a main reservoir that hold the bulk of the nutrient solution, and an attached system of buckets through which the nutrient solution circulates. Each attached bucket will be topped with a new pot lid, through which plant roots will grow, and show contain an air stone to ensure proper root oxygenation.
Advantage of DWC
- Great for water loving, rapid growing plants.
- Allows for large root mass.
- Flexible plant site sizes.
- Fewer plants with larger yield.
- Reuses water.
- Cost effective to build the DWC system.