If you are a new comer in hydroponics gardening, you should try out one of the many other types of hydroponic system before going into NFT systems. There passive an d active system available, and within these systems there are several sub-types. These include: Flood and Drain (or Ebb and Flow), Deep Water Culture (DWC), Drip feeding, Wick feeding, Nutrient Film Technique (NFT), and Aeroponics. This article touches on the construction of a DIY Nutrient Film Technique (NFT) system.
NFT hydroponic method
The NFT systems are said to be one of the most productive hydroponic systems. It is not a system for beginners, and you should try experimenting with the other types of systems first before you jump into building an NFT hydroponics system.
Figure 1 shows the basic components of a NFT hydroponic system. The water enriched nutrient solution is pumped up from the reservoir at the bottom to the top grow tray from one end. The tray is positioned at an angle, allowing the water to flow at approximately 1-3 mm of depth over the bottom surface of the tray. The flow is not too rapid and is slow enough to provide nutrients to the plant in a constant motion. The water is then drained out into the reservoir again on the other end of the tray and recycled. This system gives the plants a constant exchange of the water.
Figure 1. NFT Hydroponic System
Tools and Materials
- A reservoir
- Two pumps (submersible air pump and water pump)
- Air tube and air stone
- Grow tray with lid
- Growing media
- Net pots
- Trace the net pots on the lid and cut out the tracings to fit the net pots later once the whole structure is complete.
- Place the submersible air pump into the reservoir (with air tube and air stone attached). A water pump should be installed at the other end of the reservoir that will allow the nutrient solution to travel up into the grow tray on the higher end. Make sure that you purchase an air pump that will have enough pressure to do this job.
- Once the system has been set up, run it once with water to check for leakage. Also check to make sure that you obtain about 1 – 3 mm film of water running from the high end of the tray to the other lower end that drains back into the reservoir below.
- The make the drain hole, drill a 3.5 inch hole and fit PVC drain fitting (with the rubber end inside the grow tray) and direct the PVC pipe into the reservoir.
- Once you\’ve made sure that the system is safe from leaks, put the net pots with the plants onto the grow tray lid.
- You will need to constantly water the plants from the top during the initial growth stages until the roots can touch the film of water in the grow tray.
Advantage and disadvantage
One of the main advantages to the NFT system is the relatively low cost of construction materials.
While N.F.T. systems are one of the oldest hydroponic system and can provide you with very high yields of crops and vegetables, the system is very susceptible to power outages and pump failures. With the pump perpetually on to provide the plant roots with a constant flow of nutrients, it may fail over the course of its life because of such pro-longed usage. Added with the possible use of hard water where you will get precipitation of salt added into the solution, the pump will give up with the build up of salts and calcium. You may also run the risk of roots drying out rapidly when the flow of nutrient solution is interrupted due to pump failure. You can overcome pump failure by cleaning and maintaining the pump regularly.
Plants that provide a heavy yield tend to fall over in a NFT system. The roots are literally suspended in air, without giving support to the plant. You need to support the fruits or flowers with structure or collars to prevent them from toppling over. These include string, canes or scrog which is a simple netting stretched out over the growing area.
Use top-up solution in the starting solution to maintain the composition of the nutrient levels throughout the life cycle of your system. Refer to online or published resources on the levels of starting and top-up solutions for the type of plants that you are cultivating.
You will also need to periodically clean out the solution in the system (which should also be done after each harvest and grow cycle) and replace it with a fresh batch of solution.
Warning: Make sure that you spray paint reservoirs, grow tray, mainline as well as tube carrying nutrient solution black (or purchase black colored ones) as this will help prevent the growth of algae.
Hydroponic systems are very productive that will provide you with proven good yield. The NFT technique was the first technique adopted in hydroponics and is still used by many growers.
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