Back in the 70s, the idea of a NFT system was put into practice. In Great Britain, the original idea was developed by Allen Cooper. This technique involved tubes that promoted a gentle, consistent flow of the nutrient solution in order to feed the roots of plants. The solution that was drained from the plant’s root area was then collected into a reservoir. This solution was then recirculatedto the roots of the plants, once more.  

 In more recent years, this technique has gained a certain amount of popularity for modern-day cultivation. Basically, the same principle is used. In order to ensure the correct amount of solution flow, the tubing that is used needs to have a fall of about one percent. When using a tunnel construction, you want to make sure that your flow rate is about one litre per minute. You will also want to ensure that the root mass of the tunnel’s bottom doesn’t clog things by being too dense.

 Should this happen, you run the risk of having the solution flow only over the root’s outer layers. This means that the nutrient solution won’t reach the insides of the root mass. This will lead to poor plant feeding and plant wilting.

You can prevent this by making sure that the tubes being used aren’t over nine meters long and have at least a 30 cm. diameter. You can detect if there is a problem by observing the plants at the lowest point (the flow’s end). Here, you can observe nutrient deficiencies before they become critical. In this case, all you need to do is to increase your nutrient solution flow rate. You can also increase the strength (EC) of your nutrient solution.

Another issue that needs to be observed is an oxygen shortage. This, too, can usually be seen in the plants located at the flow’s end. One sure sign of oxygen shortage is that the plant’s roots will begin to turn brown. The plants will also demonstrate a decrease in their nutrient solution uptake. Oxygen shortage problems can be the most devastating during the phase when the plant’s fruit is forming.

One can also use enzymes than encourage root decomposition, which will lead to having fewer dead roots and, thus, the plants will be healthier. Since there will always be some dead roots, as long as you have sufficient healthy (white) roots, there’s no need for concern.

In 1982, aeroponics was initially introduced in Israel. This was just a short time after NFT systems came into existence. This type of system utilises misters which spray the roots with tiny droplets of nutrient solution. When the drops are tiny, there is a better degree of contact between the roots and the solution. This facilitates better nutrient solution uptake.

With this type of system, the roots are, for all practical purposes, growing in air. This ensures that there is always a sufficient amount of oxygen provided. This, in turn, can promote larger yields.

However, the greatest disadvantage of an aeroponics growing system is the amount of initial monetary investment involved. Not only this, but this type of system is also subject to malfunctioning. Because of this, it’s usually best to leave a small layer of water in the misting room’s bottom. This will make sure that the plants won’t lack for water, in the event of a system malfunction.

With an ebb and flood system, the plants reside in a container (box) which is periodically filled with nutrient solution. When this occurs, the substrate will soak up the solution and afterwards, the solution is pumped out. This pattern of periodically filling the box will serve to push out the older air and allow fresher air to flow in, along with the solution.

Root level oxygen shortage is prevented by not allowing the medium to remain saturated for an extended period of time. The medium must also have sufficient oxygen after the solution has been drained. This can be assured by having the pumping/draining cycle limited to 30 minutes.

The flooding frequency will mostly depend on the type of substrate used, along with the root volume of the plants. For example, clay pebbles will need more frequent flooding, since they retain smaller amounts of water. Rock wool systems will hold greater amounts of water.

The most common hydroponic system is usually the drip system. The advantage here is that a drip system is the most simplistic. In it, a clock is utilised in order to control a pump that controls the nutrient solution tank. When the clock designates it, a mechanism allows the nutrient solution to drip over each plant’s base. A nutrient solution reservoir collects the excess solution, which is then reused or drained out.

This system involves keeping the plants in a substrate that is inert. Just like the ebb and flood method, watering frequencies will vary.

These are some of the more popular recirculating systems that are in use today. Determining which one to use can depend on your gardening space and budget.