Hydroponic Systems - Continuous Flow

In comparison to aggregate culture systems, continuous flow hydroponic systems are more varied. A complete discussion of all the different systems will consume much time and digital paper space, so at this time we will only review two continuous flow systems.

One basic idea for a continuous flow system is to build a culture tank with an angled bottom to facilitate flow and drainage. Though pumps are used often, it is still best to build your tanks with an incline. Plants grown using these systems may be held aloft by grow baskets or similar devices.

Nutrient Film Technique - Easy To Build, Hard To Master

The nutrient film technique (or NFT) is a system where water constantly passes by and over the roots. There is no growing medium used. Capillary matting or air stones are used to keep the roots from drowning, and also provide aeration. However, the submersible pumps must be running 24/7. That means that this system uses a closed loop to use and reuse nutritive fluid, until tests show that the water should be changed. Plants are usually suspended using grow baskets or support collars.

The NFT technique is highly effective, but it is not easy to fine-tune for beginners, and can be especially unforgiving. If too much of the roots are submerged or are in contact with the nutritive fluid, they may rot or not get enough oxygen. Without an absorbent growing medium to serve as a buffer for moisture and nutrition,

plant damage and death can be quick. This is the technique that is most often associated with the “continuous flow” moniker.

Continuous Drip System - Tops In Control

Another hydroponic system that can be used is the continuous drip system. This system is a little more complicated to set up, but can be very effective. The idea is that your system feeds each plant individually using hoses with drip emitters at the end. These drip emitters are adjustable, so you can fine-tune the amount of nutritive fluid each plant gets.

At regular intervals, the plants get a drop of nutritive fluid. These plants are grown with a growing medium, and the adjustability of the drip emitters leaves one free to choose any growing medium.

The drip system may be powered by a pump or simply by gravity if your operation is not very large. You may build in a fluid recovery system, with drip trays under the plants leading to a reservoir.

The continuous drip system does require a lot of fine-tuning, especially considering the individualized nature of the feed system. Any widespread changes will have to be done one plant at a time.

Of course, the initial setup is also more complicated, with additional planning and laying out of the individual feed hoses. Allowing the drip emitters to water the roots too often also has the effect of drowning the roots, so be careful against that.

Comparing Drips to a Stream

When comparing these two systems, one can see major differences in execution, as well as strengths and advantages. Where an NFT system makes scaling up very easy, a continuous drip system will make adding plants hard because of the hoses. On the other hand, a continuous drip system works very well for scientific investigation because it allows a very fine level of control.

Another obvious difference is that the continuous drip system may not require electrical pumps. With large enough drip-catch and feed reservoirs, one can use gravity for feeding and manual work to transfer runoff back into the feed reservoir. This can mean major savings in electricity, and also a more reliable system that can survive long power outages easily.

On the other hand, NFT systems make full use of automation, making it very easy to run once everything is fine-tuned. This is perfect for those who cannot afford to pay constant attention to their plants, further increasing the value of the NFT system in large-scale applications.

It is also very apparent that continuous drip systems tend to be more costly (in terms of resources and time) to build than NFT systems. This should also enter your consideration.