Hydroponic Systems and how they work Part 2 - Nutrient Film Technique NFT
Gardening This system is possibly the least complicated of any hydroponic systems as it does not incorporate the use of timers to turn pumps off and on. The seeds you use need to be generated first in a propagation unit until they have an adequate root base to be placed in the system. How does it work? The equipment involves long shallow trays which come with a long lid making the system encased. There are sections in the lid in which the plants are inserted. The plant resides in a plastic pot with slits to enable the roots to grow through them. They appear like a smaller version of the inner pot employed in flood and drain systems. The trays are positioned above a water reservoir and a pump connected at one side to pump water into the trays. There has to be a good gradient so that water flows down the tray and back into the water tank. Typically the gradients used are 1:30 or 1:40 this reduces water pooling in the indents caused by uneven areas and roots. The theory is that the roots are consistently bathed in a nutrient loaded water supply and yield healthy and balanced, linear plants. The name "nutrient film" makes reference to the delicate film of roots that should ultimately develop on the bottom of the tray. It must be only a small stream of water with only the bottom of the roots underwater; this allows the rest of the root to be accessible to the air and acquire the essential oxygen essential for growth. The units come in different lengths which can hold different numbers of plants. In essence you can have any length of NFT system, however the longer the system the greater the chance that flow might be disrupted. Systems longer than 12 metres tend to get less growth in vegetation towards the end, this is attributable to the nutrients being taken up by plants closer to the reservoir. That being said this difficulty can be prevented by installing another water supply along the length of the channel. Problems I have talked about a couple of concerns already, for example pooling of water and nutrient decrease in long system models. Nevertheless there are a few more. Pump Failure As NFT systems only need a small, shallow water distribution the pumps are not very powerful. They are furthermore turned on continually meaning they get lots of activity during the process of the grow. This combined with possible salt precipitation from the diluted nutrients (particularly in hard water regions), suggests that sooner or later the pump is likely to breakdown. If you can catch this quickly then aside from the expense of a new pump, there's no real problem to the plants. Then again if this goes unnoticed it means that the roots will dehydrate in a short time and this can affect growth. Disease The plant roots are constantly soaked in water and this may lead to bacterial problems such as Pythuim. Pythuim is often known as "root rot" and can wreck your plants if it is not identified early. There are treatments available to buy that can get rid of Pythuim if you are unlucky enough to have it, however the easiest way is through prevention. This is often accomplished by replacing the water in the reservoir regularly and incorporating preventative formulations to the nutrient solution. Stability Heavy fruit producing crops can become unsteady in an NFT system. This is a result of the roots growing long and flat and not having a great deal of grip. This causes the plant to become top heavy and they drop out of the trays – not ideal! This can be overcome by bolstering the plants by using yo-yos, string or canes. This will give some stability to the plant and permit it to keep on growing and bearing fruit without toppling over. Overview Even with the issues described above these systems are great choices to demonstrate the use of hydroponics. They are an inexpensive system and a terrific choice to use as an introduction to growing your own produce at home. Sarah owns and operates her own hydroponics equipment business. This has expanded out of her love for cultivating her own fresh produce at home. For more information about this system take a look at Intelligent Hydroponics or iHydro for short
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