We are still missing some overview topic for beginners to get basic information about hydroponic systems available on today’s market. I’ve improved this original article by Tim Walker with some new photos.
Picking the Best System to Grow
By: Tim Walker, Originally Published in Maximum Yield Magazine
For most people, a simple method that is easy to maintain and not overly complicated is probably the best. Also, the most forgiving method might prove to be the best way to grow because there are fewer things that can go wrong. Choosing the best system may depend on how much time you want to devote to this venture. The problem with good old-fashioned soil (dirt) is that often it is not sterilized and contains pathogens, weed seeds or it may be highly lacking in nutrients. During this discussion we will be talking about “soil-less” methods, which means using a pre packaged growing mix such as SunshineT or ProMixT or a clean, sterilized, inert medium. A medium could be any one of many suitable products and may include; clean sand, pumice, vermiculite, perlite, clay, sawdust etc. All have been used to some degree of success and can be considered an artificial medium. A “soil-less” medium usually means a peat moss type mixture.
Should I use an NFT system, an Aeroponic system or just grow in soil? The answers again will lie in what you hope to achieve. If you are growing for profit or for maximum production then you may want to consider a faster method. If higher yields are what you had in mind, then maybe a different method is the best choice. Let’s explore all the common methods and see which is best for you.
Hydroponics in it’s truest form (not how the papers easily use this term) is a method where plants are grown in an artificial medium ranging from peat moss, sawdust, sand, gravel, rockwool. perlite etc. and are fed a strict diet of nutrient-rich water on a constant basis, so that they are never lacking in any mineral or nutrient for the entire life of the crop. Most all of these systems are great if you are an expert on nutrition and on monitoring the nutritional levels and have a good working pump system and plan to be there 24-7. If you leave or the power goes off and the pump shuts down then you have a problem. Believe it when the power for the lights or the water pump shut down for any length of time you will remember the term “Houston we have a problem!” Most people simply do not have the time or expertise to devote to true hydroponics growing.
Why then do people choose hydroponics or similar versions of this system? Simply because the yields can be much greater than traditional garden yields. A study once showed that an acre of field tomatoes could produce on average x number of kilograms or lbs per acre per year. Growing in a greenhouse for 11 months of the year using hydroponic methods under ideal conditions, demonstrated that the yield difference could be as much as 11 times (11x kg/lb per acre) greater than in the field. For one thing, the field crop could only produce a single crop per year in a moderate climate, whereas the indoor garden could produce two to three times per year depending on the cycle. On the other hand the outdoor crop was not monitored as closely and the amount of fertilizer applications, pruning, and general maintenance was much less. Growing outdoors the danger was being at the mercy of the weather, be it ideal condition or horrible conditions. The trick is achieving the best of both worlds and choosing the correct methods can do it. Growing indoors under ideal climate conditions but using modern growing methods is ultimately the best route to take.
Let’s look at some of the techniques or cultural options open to growers.
The NFT System
The NFT or Nutrient Film Technique is a system where the roots of the plants are held in a trough or plastic film and a continuous light river of water runs over the roots constantly. The water is then recirculated back into a main reservoir or tank and then sent out to the same plants over and over. The advantages are increased aeration that supplies plenty of oxygen as well as nutrition. Every couple of days the water is tested and remixed with the correct ratio of nutrients added to the tank and the water topped up again. There have been several modified and updated versions of this, such as the hydro canal system, and NFT is still used to some degree today, mostly in the UK.
Capillary Matting System
This system uses a similar technique where the plant roots are grown on large fiber mats made of a water wicking substance. The problem with these was that often the roots only fed at the bottom level or the materials, were too porous, encouraged algae growth and were usually expensive. Not many crops are produced today except where bottom feeding (i.e. African violets for example) is needed.
Aeroponics is growing in a 4-6" PVC pipe or tube with holes cut in it for the plants to sit in. Usually a small mesh basket is placed in the hole with the roots sitting in the basket filled with clay pellets or coir (coconut fiber). Inside the pipe a small micro jet mister, something like you see spraying in the produce section of the store, is used. This mister supplies a high level of oxygen plus nutrition to the roots of the plants. The water then runs down the pipe that is usually slanted a few degrees toward the main pipe or return tank. The water is then remixed and returned out under pressure to again be mist fed at the root zone of the plants This method was popular in the 1990s and saw some remarkable growth, incredible root systems and often an increase in the crop cycle time. Peppers, basil and other crops produced in record time with remarkable growth. Unfortunately the drawbacks were the reduced size of the plant you can produce and possible algae growth. Another drawback is in the event of power loss or if the pump shuts down you have a very short time span in which to repair it or find alternate power before you begin to loose your entire crop.
Essentially the bucket system uses five gal (20 litre) black or white plastic buckets with a hole cut in the lid to support a three to four inch plastic pot or mesh (net) pot filled with clay or gravel. The plant goes into the mesh pot that sits ¾ of the way below the lid and the roots drop through the media and search for the nutrient rich water, which is circulating in the lower portion of the bucket. A 5/8"-3/4" inch thru-hull marine type fitting goes on the bottom of each bucket. In one central bucket or tank (often made using a RubbermaidT type plastic container) is the reservoir tank that holds the return nutrient water. A small pump is used to send the nutrient “back out” to the buckets through PVC pipe and fed into each pot by black spaghetti tubing. The incoming and freshly oxygenated water is dripped on to the top of the mesh pots providing new water, nutrient and oxygen for the plants. These systems can be constructed easily at home and usually have 6-10 bucket sites per pod. Each pod is usually set out in a star or circle formation and the thru hulls are connected with rubber watering hose of the same size 5/8" or ¾"that returns the water back to the main reservoir. Bucket systems work well but again the drawback is forgiveness. If the water and nutrient are changed regularly and the pump is never shut off plants will grow at an accelerated speed, but if the power ever shuts down or the pump goes you can be in trouble in a short amount of time.
For example of Bucket (bubbler) system see this topic:
Chamber or Wheel system
One of the best examples of this is system Omega Garden. Although these systems achieve speedy growth and unbelievable root systems they are by all accounts not very practical and high in maintenance. These systems are designed to provide extremely high light (phototropic periods) and increase the plants ability to grow and mature at an accelerated speed in a high-density area. Again the positive is high-speed growth potential and the negative is the unforgiving factor should something go astray or the power shut down.
Flood Tables (a.k.a Ebb&Flow)
The flood table system uses a plastic table with raised sides capable of handling about 2 ½" of water and uses an ebb and flood type practice. Ebb and Flood system is essentially a fill the tub and drain the tub concept all done in a matter of minutes. Usually plants are grown in stone wool (rockwool) blocks or in small mesh or net pots. The pots are filled with a media that will not stay saturated for long, but allow the roots to wick up nutrient water, dry out again very quickly and yet allow for good oxygenation. Usually a timer is set to turn on the pump and the bench “floods” for a time period that raises the water level up to about 1/3 to 1/2 the level of the pot or block. After this flood period the timer shuts the pump off and the filling subsides and the water begins to drain back into the tank or reservoir. By allowing for a dry out period of several hours the roots can uptake the necessary nutrients and still not drown. The lighting would be on to coincide with the time period of the ebb and flood.
Container gardening is where plants are grown in a container made from either plastic, ceramic clay or fiber. The containers usually are a round pot, pail or a plastic growing bag shaped on the bottom like a paper bag. The chosen container is then filled with a sterilized and artificial mixture. These mixes are predominantly made from peat moss with the addition of perlite, pumice, vermiculite, sand, sawdust or other amendment.
Some mixes contain added wetting agents or moisture holding agents and some contain a charge of nutrient to initiate good plant growth. Other mixtures may include coir (coconut fiber) or loose rockwool instead of peat moss. The size of the container will often dictate the size of the plant growth desired.
The idea is to plant the plants in these containers in a controlled environment with nutrient being added either by means of an automatic drip or sprinkling system or by hand watering. The disadvantage is sometimes the growth is less accelerated than with some of the high tech methods and hand watering is laborious. Also, hauling in and out large bags of “dirt” is cumbersome, but often the old or used dirt can be spread on the outdoor garden or lawn as a great addition to the garden. The big plus to container gardening is that it is so much more forgiving than many of the other methods.
First of all an organic-based material, such as dirt, often assimilates organic matter more easily than in a water culture method. Secondly, if a day of watering is missed or a pump shuts down the plant will usually have residual moisture left over from the last watering session.
Controlled Environments vs. Uncontrolled
One has to think why we have indoor farmers that produce high tech crops such as our hothouse peppers or tomatoes and why we have field grown crops such as tree fruits, cereal grains and field vegetables. The rationale is simple economics. A lot more can be produced outside at a slower, less controlled rate cheaply and a lot higher quality fruit can be produced in a high density controlled indoor environment. The difference is cost, time and error. If the indoor farmer forgets to water, it is a catastrophe, whereas the outdoor farmer often just hopes for rain on an un-irrigated field. For a grape grower producing a field crop but using a drip irrigation system, it is sort of the optimum of both worlds. He cannot control the weather, but he can work in harmony with it only adding water and nutrient when he sees the need. Both of these types of growers can also choose to produce organically as well, if they so choose.
As in all systems, learning the little subtle tricks of growing in any particular culture is important. All of these systems mentioned have been used to a high degree of success. The most difficult part is creating a system that works well and is both low maintenance and forgiving. The more recent trend has been to go back to container growing with an artificial soil less mix type medium or an organic mix. Either hand watering or automated irrigation is usually the chosen method, with automated being the more prudent from a time and labor point of view. When deciding which system works best speak with your sales rep or store manager and weigh the options and choices against what you want to accomplish. If you’re serious and passionate about this, then maybe a more complex method will be fine. If you are looking for a more relaxed and simple system, then another may be right for you,
As with any growing method you must supply ample air supply and circulation by using good quality fans and placing them properly. You must also provide optimum light, whether using artificial HID lighting systems indoors or providing natural light in a greenhouse or cold frame. Using a high quality nutrient and mixing it with clean PH neutral water is also critical. If you’re not on regular city type potable (drinkable) water then you need to look at your water source and have your water tested. The best system in the word will not work properly if your fertilizer is poor or your water is bad. Choosing high quality fans, lights and fertilizers will complete the circle of success. Don’t use this as a place to cut corners and “save” money.