Beginners’ Corner: Hydroponics Systems
By Cosmo MacKenzie • 3 weeks Ago
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By Cosmo MacKenzie • 3 weeks Ago
We all started in the same place; with three simple questions about hydroponics systems. Which is the easiest? Which is the cheapest? Which is the best? Well, like so much in life, these questions are all subjective. If you take up hydroponics and foster a passion for it, you’re likely to spend much of the rest of your life debating these very questions.
This guide should act as an introduction to the basic hydroponics systems that you’re likely to come across, as well as provide you with helpful tips in general. It’s all about building a knowledge base. The best way to do that is through experience and research. There’s nothing to stop you from watering your plants by hand. Hand watering isn’t easy to get right though, and in the confines of a grow room it can be an absolute nightmare. Irrigation systems allow for a greater level of control and regulation. All hydroponics systems share one thing in common- a reservoir, or tank in which the nutrient solution is stored. Different systems are distinguished by the way in which that nutrient solution is delivered to the plants.
The Wick system is the simplest irrigation method. If you’re planning to build your own hydroponics system at home, this is the easiest kind to build (with a drip feed system not far behind). It also serves as a great jumping off point for anyone aiming to understand all the other hydroponics systems. You start with a tank or reservoir in which to put your nutrient solution. On top of the tank you construct a tray in which your plants sit. A wick, like a candle wick, is then fed from the tray, directly into the nutrient solution. In theory the wick sucks up only as much nutrient solution as the plant needs to grow. In practice it’s very hard to properly regulate the pace at which the nutrient solution is absorbed. Admittedly there are no moving parts, so the chances of a mechanical failure are nil. If you have the time, it’s well worth setting up a wick system at home for an individual plant- if for no other reason than to see how the hydroponics systems process has evolved. Then again, you could just take it as read and move on.
Low maintenance systems can breed laxity.
In a DWC system, the growth medium sits in a net pot above the nutrient solution, with the root system growing downwards, directly into the nutrient solution. Air is fed into the root system by way of a bubbler set into the bottom of the tank. This oxygen rich environment encourages large root growth. DWC systems tend to be self-contained units servicing one plant at a time, making them very popular for use with specimens and mother plants. They don’t take up much space and they don’t have too many moving parts, meaning there are fewer chances of mechanical failures and potentially less of a need for maintenance.
Low maintenance systems can breed laxity. Whichever hydroponics system you choose to go with, abiding by a regular schedule of standard checks (pH, EC, humidity, temperature) is essential and, where possible, should be done daily. pH levels can change incredible quickly. Read ‘Bill on bigger yields’ to better understand how and why plants alter the pH of their environment. In a DWC system, those changes can have a fast acting effect. The chance of stagnation is a very real threat, should your air pump fail.
The dripper system is the most accessible hydroponics system for anyone with even a passing familiarity with conventional gardening techniques. The nutrient solution is fed from the tank, via a pump, into a system of pipes and tubing. Feeding tubes, or drip lines, are tipped with stakes, which are stuck into the growth medium from above. The retention level of your chosen medium determines which type of stakes you should use, with different stakes releasing water at different speeds, or at varying volumes. There are two different classes of dripper system. The recovery system, or recirculation system, feeds the excess, or run off nutrient solution back into the reservoir, allowing it to be recycled back into the system. The non-recovery system, or run to waste system, feeds any runoff out of the system, either into a drain, or usually into a second tank. The recovery system is more economical, whilst the non-recover system sacrifices savings in costs in favour of a healthier and more manageable process. The relative savings of the recovering system needs to be weighed up against the higher potential for problems to arise. The dripper system is simple to use and adaptable. Most growth mediums can be used in a dripper system and individual plants can easily be switched in and out of the system when required. Soil based substrates retain a large amount of water; this means that if there is a problem with your system you have a relatively large window in which to fix the problem before your plants start to dry out. This is by no means true of all hydroponics systems.
The dripper system’s main advantage is also its biggest disadvantage; all of the plants in the system are fed from a single tank. Whilst this makes maintenance a whole lot easier, it does call for a consistency in your crop. Even if you’re growing a single crop of the same plant, there’s a chance that different environmental factors in the different parts of your grow room will influence individual plants to have different needs from one another. If one of your plants is showing the signs of nutrient deficiency, but another is showing signs of nutrient toxicity, you’re somewhat scuppered by the fact that both plants are serviced by the same nutrient solution. If you haven’t got the facilities to remove a particular plant and attend to it separately, then your only real option is to choose which plant you plan to save and scrap the other.
The high level of automation in a dripper system means you can have more accurate and regular control over feeding schedules. Plants benefit greatly from consistency, and who’s to say you’re going to be free to feed your plants at six in the morning, every single morning? It’s also a great benefit if you plan to go away for a few days; just remember that leaving your hydroponics system unattended for any great length of time is a decidedly bad idea. Dripper systems are prone to salt build ups, which can cause blockages in the pipes. There’s also a chance of some of your growth medium being washed into your reservoir, which can also cause blockages.
The risks are higher, but so too are the rewards.
The NFT system is seen by some growers as the preserve of enthusiasts. Those same enthusiasts have a tendency to claim NFT isn’t really all that taxing. If you have an NFT adherent to help you along the way, then you’re onto a good thing. If you don’t then your best bet is to stick with the simpler systems to start off with. Still, it can’t hurt to build your knowledge base. NFT works by pumping nutrient solution from the tank onto a spreader mat, which lies on a sloping tray. Nutrient solution spreads as a thin film across the mat. Plants are rooted in rockwool cubes and roots spread freely across the tray. This gives the roots a large and ready supply of oxygen. NFT systems require precision and experience. All the problems you potentially face with the other hydroponics systems are manifold with an NTF system, and the pace at which those symptoms can spread is also increased. NFT systems do allow you to elicit greater control over growth conditions; everything from oxygen levels to varying the pH during the growth cycle in order to stimulate better uptake of individual elements. The risks are higher, but so too are the rewards.
Nutrient solution is pumped up from the reservoir into the bottom of a shallow tray, or growing bed, which the growth medium rests in. The tray fills to a particular level, at which point the pump switches off and the nutrient solution begins to drain back down into the tank. This process pushes stale, poorly oxygenated air out of the root zone, then sucks in highly oxygenated, fresh air as the solution drains. The ebb and flow motion has a natural washing effect on the root zone which acts to minimize excessive salt deposits and offers exceptional aeration of the roots, encouraging large, healthy levels of growth. Unfortunately, this high level of root growth can work against you, with roots clogging the pipes. Excessively high temperatures have the potential to dry out relatively exposed roots- which isn’t a state from which your plants will quickly recover. The relatively shallow depth of the tray can also be a major problem for bigger plants. It’s a problem which is easily resolved- by offering additional support to your plants- but it is a problem none the less. Algae forms when excess light, or light pollution, falls on the surface of your nutrient solution. Flood and drain systems are susceptible to algae, as indeed are most hydroponics systems to one extent or another. Wherever possible, you should cover your nutrient solution to protect it from the light. Also, like the dripper system, ebb and flow systems are susceptible to growth mediums breaking up and clogging the system.
Of course a number of different hydroponics systems exist, and more are being developed every year. If you visit your local Hydroponics store, you likely run into the following two systems;
RPS is a derivative of the flood and drain system, but instead of using the conventional tray system, it utilized a ‘brain box’ which feeds individual pots connected to a larger system. RPS has all the benefits of a flood and drain system, with the added benefits inherent to individual pots, and offers the potential for better utilisation of your available growing space
The Autopot system uses gravity and a smart valve to feed your plants. Low quantities of water are fed to each plant, which are only allowed access to more water once they have utilised that which is already available. It is a non-recovery system so the pH and EC levels are generally constant. You can expand the system to your heart’s content (increasing the size of your reservoir according to the number of pots) and the fact that it doesn’t use electricity means that it is completely noiseless. By all accounts, refilling your reservoir is about as taxing as the process gets, which is bordering on self-sufficiency.
The best way to understand any hydroponics system is to see it in operation. Your local Hydroponics shop should be more than happy to show you how a system works and give you advice on which hydroponics system will best suit your needs, and if you’re going to invest in a system they’ll be even happier. They don’t bite (well, except this one guy in Liverpool, but that’s a whole other story). Investing in a new setup can be a sizable outlay, so it’s well worth doing your research before putting any cash down. Reading this article is a good start, subscribing to Hydromag would be an even better one! Finally, if there’s one thing I wish someone had told me when I started out it’s this; it’s almost inevitable that you’re going to have failures along the way. It’s part of the process. There are hundreds of things that can go wrong; experiencing them first hand is the only way to properly learn about them. It’s when the same things keep going wrong that you need to start asking some hard questions. Questions Hydromag would be more than happy to answer for you.
If you haven’t already, you’ll need to choose a substrate to grow in with our guide to growth media.
Before you can put either to work, you’ll need to plan your indoor garden or grow room.
This article was originally published in Issue 003 of HYDROMAG (January – February 2013).
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