An Intruduction To Expanding Hydroponically
Flood & Drain- Otherwise known as Ebb & Flood, at its simplest form, there is a tray above a reservoir of nutrient solution. The tray is filled with expanding medium (clay pebbles being the most common) and planted directly, or pots of medium stand in the tray. At regular intervals, a segmen timer causes a pump to fill the upper tray with nutrient solution, after which the solution drains back down into the reservoir. This keeps the medium regularly flushed with nutrients and air. To find out more see our Flood & Drain article.
NFT – In NFT, the plants grow through light-proof plastic films placed over shallow, gently sloping channels. A steady flow of nutrient solution is maintained along the channel, and the roots grow into dense mats, with a thin film of nutrient passing over them (hence the name of the technique). To find out more please see our NFT article.
Aeroponics – In Aeroponics a fog or mist of the nutrient solution is sprayed over the root system. This has the advantage of minimizing water usage as well as giving the roots ample access to oxygen. Aeroponics is mainly used for cuttings and seeds because the system needs to be quite large for older plants. To find more please see our Aeroponics article.
Contrary to some expectations, the roots of the plants grown hydroponically are not usually totally submerged in water. As having the root totaly submerged in water would be counter-productuive, the reason for this is oxygen is a key factor to all hydroponic systems.
The idea of hydroponics might still intimidate some people, most gardeners prefer and enjoy the simple, quick and easy process of Hydroponics. It is no more complicated than traditional gardening techniques, and the same expanding principles apply to the both. Although slighty more technology is used in Hydroponics you should not be daunted by this.
Choosing the best method for you.
There is often great debate about the best method of expanding the truth is it depends on the grower, it is certainly true that advanced techniques like aeroponics and hydroponics display rapid growth rates which astonish growers who have previously worked with soil this is due to the water having the perfect amount of oxygenated nutrients contained within it.
What the grower must understand where they previously had soil acting as a buffer as well as providing nutrient, in hydro & aeroponics it is down to the grower to ensure the pH and nutrient remain stable and accurate.
Many soil growers enjoy the low cost & low maintenance of working with soil despite the traditionally slower growth rates by adding air pumps porous air rings many growers report up to 50% increase in yield along with growth rates than can only been compared to aeroponics.
In conclusion it really depends on an individuals circumstances many growers use a combination, keeping stock or mother plants in soil, Using Aeroponics for rooting cuttings enabling rapid root and vegetative growth at very early stages and flowering in N.F.T or flood and drain.
Flood and Drain
Flood & Drain or Ebb & Flow is a very popular method of expanding especially for first time growers as it is easy to gage the moisture within the cubes and making it easier for the grower to coax the roots out without over watering.
The best medium for Flood & Drain tables undoubtedly PH stable expanded clay pebbles, which can be laid directly on the bed or put in pots. You will need to cover the table to exclude light or algae will be a big problem. Flood and Drain uses two cycles to feed oxygen and Nutrients to the roots.
These are the Flood Cycle, and the Drain Cycle.
You flood the roots with nutrients, and expel all “dead air” from around the roots.
After the Flood Cycle (2 to 15 mins) the nutrients drain quickly to draw or “suck” fresh oxygen into the roots as the nutrients drain out and at the same time, leaving the roots damp with nutrient.
Sound Complicated? It’s as easy as Pump on and Pump off!
We usually would advise people to keep an eye on their plants. If the stem and leaves wilt, then increase the number of floods. If the leaves wilt with yellowing of the leaves; you may have too many floods and the roots are drowning or rotting. Immediately increase the amount of time between flooding.
Nutrient Changes should be performed regularly, if you have no electronic test equipment. Flush the expanded clay every 4-8 weeks with water, just in case any nutrients build up on the expanded clay. This can occur if the plants use a lot of water, and leave the nutrient behind. This is called salt build up. Some people get this problem, some don’t.
Clean the filter if the system is not draining quickly. Flood and Drain is a very high powered system, and will give you much higher yields than similar systems. You will have fun with Flood and Drain.
Nutrient Film Technique is uniquely simple. It involves a shallow film of nutrient solution constantly recirculating past the roots of your plants. Nutrient solution is pumped from the tank to the channel, over the plants roots and back into the tank.
It´s this recirculating film that differentiates N.F.T from other hydroponic expanding techniques. Sperader Mats are used on N.F.T systems to make sure the water spreads evenly across the channel, it also provides an easy way for the roots to grow throughout the spreader mat and hold themselves above the water alowing the root better acsess to oxygen.
The key to N.F.T is to have the root system of the plants well established. The most common fault in N.F.T is trying to apply the plants to the beds before they have established a good root structure, this causes to Rockwool cubes to instead become water logged this can cause detrimental effects upon your plants.
If you are concerned about this problem you can either put the N.F.T. pumps onto a timer so they are running periodically, or alternatively increase the slope so the plant has less access to the water.
Once you have become familiar with the basics you may wish to experiment with Aeroponics to attempt to increase your yield. However we must advise caution with this and advise any aeroponics system to be a Dual Flow system using Aeroponics & Flood and Drain or N.F.T.
As aeroponics sprayer nozzles are notorious for blockages, for this reason we also recommend aeroponics systems should be run with Liquid Oxygen to help prevent blockages.
In aeroponic systems the plants grow in an enclosed chamber and require a water pump, air pump, air stone and sprayer nozzles. The spray nozzles are placed within the grow chamber so that the roots of your plants are sprayed directly with your nutrient solution and keep them close to 100 per cent relative humidity. This allows the roots to grow in the air and get the maximum oxygen possible to grow.
The best use of an aeroponic system is for propagation. It stimulates the best growth for rooting plants and results in strong roots and good yield. One of the most popular uses of Aeroponics is in the propagation stage of the plants growth. It´s used to get the root thought the starter cubes and then plants are commonly transplanted onto the system in which is designed for more mature pants.
The rainforest is a popular propagation unit in that it has a deep growth chamber, which is half filled with the nutrient solution, thereby making it an aero-hydroponic system. A submersible pump draws water up a central tube to the top of the root chamber where the jet of water hits a curved plate, causing the solution to be sprayed horizontally onto the roots in the spray zone.
The circle of water (not a true spray) created then falls back into the reservoir to provide gas exchange. It has no extra aeration for the nutrient solution. Roots also grow in the spray zone. The spray is created by injecting nutrient solution, at relatively low water pressure through strategically placed nozzles.