Do you want to turn your yard, back garden or even just a corner of your kitchen into a hydroponic garden? Great idea. The point is that there isn’t one hydroponic system.
Hydroponics is a vast field, with many different scientific and technological solutions, each with its peculiarities, each with its advantages and disadvantages.
This is why we need to see different types of hydroponic systems all in detail, because choosing the right one for you can make the difference between a successful garden and a happy gardener and, well, a less gratifying experience.
What are the types of hydroponics systems?
There are seven types of hydroponic systems: the Kratky method, deep water culture (DWC), wick system, ebb and flow (or flood and drain), nutrient film technique (NFT if you like acronyms), drip system and aeroponics.
These system also vary in complexity, the simplest being the Kratky method while most people regard aeroponics as the most advanced. Still, without further ado, here are all the hydroponic systems in detail.
Types of Hydroponic Systems And How They Work
1. The Kratky method Of Hydroponics
This is a very rudimentary system, so much so that it is outdated and only used by amateurs who want to dip their feet into hydroponics or just for fun.
Still, it gives the idea of the key principles of hydroponics: all you need is a jar or tank and the nutrient solution. You will put your plant or plants with the areal part out of the solution and the roots dipping into it.
It’s that simple. You will only need to make sure that the stem and leaves are out of the nutrient solution, and for this you can use a grid, a mesh pot, or even the shape itself of the container. A simple vase with a narrow neck will do the job perfectly well.
You must have seen sweet potatoes grown in vases; that’s the Kratky method for you.
Note that some people do not even use a nutrient solution, but simple water.
This System Has Some Great Advantages:
Still, It Has Some Disadvantages That Determine And Limit Its Use.
So, this is a very amateurish method; fine if you want to have a small decorative plant in a beautiful vase on your table, but not if you want a reliable source of food and even less if you want to go professional.
On this note, there is currently a trend to transfer epiphytic orchids to this method, as they are naturally suited to living without soil.
2. Deep water culture
This is the “mother of all hydroponic systems”, the most classical, even historical method we have. However, it is not a favorite with hydroponic gardeners, and we will see why in a moment. It is fairly simple and a “step up” from the Kratky method.
It is based on a tank (called a grow tank) where you have the nutrient solution and at least an air pump to provide oxygen to the roots.
This is at its simplest. Having an air pump allows you to grow more plants and more successfully with a single grow tank.
However, the basic model is seldom ever used. Usually, gardeners prefer to have two tanks and two pumps:
The Deep Water Culture (DWC) Has Some Advantages:
Still, It Is Far From Perfect:
There are two more things to say about DWC. You can improve aeration with a very porous and inert growing medium; however, because the solution is stagnant, this will tend to become an ideal home for algae and bacteria.
Finally, the Kratky method is often regarded as a rudimental deep water culture system, so some people classify within it.
While it can be used for large gardens, it does give you some control over the feeding and aeration of your plants, deep water culture is currently falling out of luck with professional gardeners because of its many disadvantages.
3. The wick system
I like this method; it is simple but ingenuous. It is not the best hydroponic system by any means, but what I like is that it solves many problems of deep water culture with a very simple and cheap solution: a wick.
With A Wick System You Will Need:
Simple. No water pump and, if you really want, you may use an air pump for extra aeration.
How does it work though?
You will simply dip the wicks into the reservoir (make sure they get to the bottom) and put the other ends into the grow tank.
Add some solution to the grow tank so that the tips of the wicks are in it; fill the tank with the growing medium and plant your beloved lettuce or flowers…
What happens next?
Nature and physics will do all the rest: because of a phenomenon called capillary action, which plants also use to move water within their bodies, the nutrient solution will slowly but regularly and constantly spread from where there is more to where there is less. Just like it does in a sponge.
This means that as the roots absorb the solution, the tips of the wicks will naturally absorb it from the reservoir.
A bit like a plant will absorb nutrient and water from the ground according to how “thirsty and hungry” it is, so will it in a wick system.
But there is another “trick” that makes this system very convenient and ingenuous… You can put the grow tank above the reservoir and place a hole in the bottom; this way, the excess solution will not stay in the grow tank, causing stagnation and possible infections, but it will be recycled very simply and efficiently back into the reservoir.
This Method Has Some Obvious Advantages:
Even This Method, Though, Is Far From Perfect:
4. Ebb and flow (or flood and drain)
By now you must have seen that the key problem that hydro ice has faced in its development has not been how to bring nutrients and water to the plants, but how to provide oxygen and aeration. The first solution came with the ebb and flow system.
The principle is to irrigate the roots regularly and for short periods of time. This way, they will not be in water continuously but have the time to breathe, without drying up completely.
To Set Up An Ebb And Flow System, You Will Need:
Of course you can also use a growing medium with ebb and flow; actually it is advisable, but your garden will still work without. We’ll see what it implies in a moment.
How does it work? Put simply, you will use your reservoir to mix in the ingredients, then, the timer will tell the pump when to send the solution to the grow tank and when to drain it.
This way the solution will be available regularly but in between the irritations the plants will “have their feet dry”.
Here, however, is the big point: how to set the irrigation times?
This is the key skill you will need for an ebb and flow system. You will irrigate, in fact in cycles. A cycle has two phases: an irrigation phase and a dry phase.
Usually there is one irrigation phase of 10-15 minutes every two hours of daylight. As you can see, most of the time pump will be switched off.
To be precise, the minimum irrigation phase is usually 5 minutes but for most gardens you will need longer time.
What is more, we said, “Every two hours of daylight;” this includes any time where you have light on (grow lights).
You see, plants do not need as much nutrition and water when they do not photosynthesize. If there is no light, their metabolism changes.
So, the number of cycles per day depends on the number of (day) light hours you plants get; on average, this is between 9 and 16 cycles a day.
It all depends on the climate, the temperature, atmospheric humidity, as well as on the type of crop you are growing.
“How about at night,” you may ask?
In most cases you will keep your system at rest during the night. However, if it is very hot and dry, you may need one or two nighttime irritations.
Finally, if you use a growing medium, this will hold the nutrient solution for longer and then release it slowly to the roots of your plants; so, you can have fewer irritations and at longer spans.
However, the irrigation time itself should be a bit longer (about one minute), because the growing medium takes some time to soak with the solution.
Advantages Of Ebb And Flow System
Now you know all the basics of the ebb and flow system, let’s look at its advantages:
Disadvantages Of Ebb And Flow System
On the other hand this system is not a favorite with amateurs and people who are new to hydroponics for good reasons:
On the whole, I would only suggest the flood and drain system to experts and professionals. It is not really suitable for you if you want an easy to understand and run system, a very cheap one or one you can run at a very low cost.
5. Nutrient film technique
In the effort to find a solution to the problem of aeration, researchers have developed yet another system, NFT, or nutrient film technique.
With NFT, you will only provide a thin layer (a “film”, in fact) of solution at the bottom of a fairly deep tank. By doing this, the lower part of the roots will receive nutrition and water, while the upper part will breathe.
When this technique was developed, researchers discovered that plants adapt to it by growing roots that reach the film and then spread horizontally.
So, don’t worry if your roots look a bit like a mop pressed against the floor; they are meant to be like that.
The important technical feature of this technique is that the grow tank needs to have a slight angle; it is not perfectly horizontal.
In fact, the nutrient solution will enter the grow tank on one side and flow down a gentle slope to a point where it is then collected and recycled.
It is a matter of a few degrees, as you don’t want your solution to stagnate but you don’t want it to flow away too fast either.
To Set Up A NFT System, You Will Need
The components you need are very similar to the ones you will need for DWC:
It is fairly simple. The main technical problem is the inclination of the grow tank, which is resolved quickly by buying a kit.
If you want to set up one yourself, maybe tailored to your space and needs, however, the ideal inclination is 1:100.
This means that you need to go down an inch or centimeter every 100 inches or centimeters. The angle is 0.573 degrees if you prefer this way of measuring.
But how about the growing medium? Most hydroponic gardeners prefer not to use a growing medium with nutrient film technique. There are some practical reasons for this:
This System Has Some Advantages:
There Are, However, Also Some Disadvantages:
Thus, this technique solves the problem of aeration and it is good if you want to grow leaf vegetables, if you are concerned about root health and if you want to use little water and nutrient solution; on the other hand, it is not suitable for many plants and it may have some “glitches” that can be pretty troublesome.
6. Drip system
The drip system offers an excellent solution to the “big problem”: aeration. At the same time, it also provides constant nutrition and watering with a pretty simple concept: use pipes and hoses and a growing medium.
It is very much linked to drip irrigation in soil gardening, which is becoming very popular and is now basically the norm in hot and dry countries, where you will see long pipes and hoses used to irrigate crops, saving water and preventing evaporation.
This system was developed thanks to plastic pipes and hoses; these are flexible and cheap, and they have made drip irrigation and the hydroponic drip system possible.
It is easy to understand how it works: you use pipes and hoses to fetch the nutrient solution from a reservoir and send it to each individual plant.
Then you drip it or sprinkle it on the growing medium which will release it slowly.
This also allows the homogeneous distribution of nutrient solution. The advantages, especially if you want your crop to be uniform, are evident.
But What Will You Need For A Drip System?
There are two connected areas of expertise you will need to develop: the growing medium and irrigation (cycles). Let me explain.
With this system the choice of growing medium is fundamental; each has different properties, advantages and disadvantages.
What is more, the choice of growing medium also affects how and how often you will irrigate your plants.
This of course also depends on the crop, climate and even the place where you grow you plants. However, how long the medium can hold on to the nutrient is a key factor to take into consideration.
You can range from continuous irrigation, where you will drip moderate quantities of the solution to your plants uninterruptedly to long irrigation cycles.
For example, you can use continuous irrigation if your growing medium is hydroponic expanded clay; on the other hand, with rock wool you will irrigate every 3 to 5 hours.
You will soon get the idea of how to regulate the irrigation cycles for your own system. It will need, however, some trial and error because no garden is the same.
Well Then, Let’s Look At The Advantages:
Even This System Has Some Small Disadvantages Though:
Before moving to the next system, I would like to mention a variation of the drip system: the Dutch bucket system.
With this system you grow plants in individual buckets, most often with a lid and of dark color, as this prevents algae growth.
The hoses go to each bucket and you can have “individual gardens” and, what is more important, microclimates for each plant. This is by far the best solution for large plants, like fruit trees.
Just by changing the growing medium (mix) you can obtain different patterns of nutrient solution release, for example, and suit them to your individual plants.
Similarly, you can change the irrigation with the size of the hoses, with sprinklers and droppers etc.
If I may give you my personal opinion, the drip system is my favorite by far. It is simple, cheap, flexible and fairly simple to manage.
What is more, it gives perfect aeration and full control on the irrigation of each plant.
Given the small disadvantages it has, if I were asked which system I would generally suggest above all, it would be the drip system.
Aeroponics is possibly the hydroponic method that looks most advanced, high-tech and futuristic.
However, this too has been around for quite some time, as the term was coined by F. W. Went in 1957. What is more, it too was developed to solve the “big question”: how to aerate the roots of plants effectively.
While it looks like something out for a science fiction movie, the concept is quite simple: use a system of pipes to send pressurized nutrient solution to the plants.
When this passes through the nozzles it is sprayed to the roots in the form of droplets.
This means that the roots will receive moisture and nutrients but also be able to breathe freely.
However, as a consequence of this, you will need to keep the roots of the plant in an enclosed space, which is called an aeroponics chamber, and you will insert them into it through holes with flexible rubber collars. These are just technical solutions to a simple but effective concept.
With aeroponics, you will irrigate for very short times and very frequently. The exact frequency of a cycle will depend on the type of crop and on the climate, but it will also depend on how much pressure you use in your system.
In fact, there are two pressure systems used in aeroponics: LPA (low pressure system) and HPA (high pressure system).
With HPA, you have irrigation cycles that can be as short as 5 seconds every 5 minutes. This should give you an idea of the difference with ebb and flow or drip irrigation hydroponics.
Of course, you will also need to use a good pump, but what is more, you will need to refer not just to the capacity of the pump (how many gallons per hour it can shift, or GPH), but to its pressure power, which is measured in pounds per square inch (PSI).
Finally, you cannot use a growing medium with aeroponics; this is out of the question.
The reason is simple: you can’t comfortably spray the roots of your plant with the nutrient solution if you have solid matter between the nozzle and the roots…
Having said this, research and experience have shown that even deep root vegetables grow well with aeroponics.
Aeroponics gardens can be of different shapes, but a very popular one is that of a triangular prism with the two triangles as sides and one of the rectangles as the base.
Here you will find that the nozzles are usually on two levels along the two rectangular sides, a set higher up and then a lower row. This allows you to irrigate the roots from different angles.
Things You Need To Setup Your Own Aeroponics System
Most people will order to buy an aeroponics kit, but if you want to build your own, here is what you need:
Note that you will not need an air pump; the roots are perfectly aerated and even the droplets aerate when sprayed.
Aeroponics Has Quite A Few Advantages:
Having Said This, Not Even Aeroponics Is Perfect:
Aeroponics, on the other hand, is very promising from the point of view of innovation.
We now talk about “fogponics” for example; this is a development of aeroponics where the nutrient solution is turned into a very thin mist and sprayed.
Aeroponics is certainly very appealing if you like cutting edge technology; it has the great advantage over other hydroponic methods of having low water and nutrient consumption and high yield at the same time.
On the other hand, it is only suitable for indoor or greenhouse gardens and it heavily depends on the power supply.
So many types of hydroponics… A difficult choice
As you can see, there are a lot of different hydroponic systems, each with its “identity and personality”; we go from the simple Kratky method that would look great in an art gallery or museum, to the ingenious but very natural wick system to aeroponics, to the one you would expect to find on a space ship…
It goes from the jug with a sweet potato school children grow on the window sill of their classroom as a science experiment to the labs and gardens of the International Space Station.
What is more, each type has branched off into a series of variants; so, the Dutch bucket system is a “sub sector” of the drip method, for example, and fogponics is “misty” form of aeroponics…
If on the one hand this may look daunting at first, now you know all the details of each system, as well as the pros and cons, you can look at it from another perspective…
You can now look at these many methods as different options and solutions, as a series of possibilities and systems that you can choose from.
So, now, start with what you need;think about your space, what crops you want, how technologically inclined you are, if you have a lot of time or you prefer an “easy life” etc…
Then, go through the different methods again, and I am sure that you will find the one that makes for you!
After many years as an academic in London, Adriano Bulla became a writer, publishing books like A History of Gardening, Organic Gardening and Elements of Garden Design; he then decided to become a gardener, following his childhood dream, and has been following his dream writing and gardening professionally in Southern Europe, where he has specialized in new and innovative organic gardening fields and techniques, like permaculture, regenerative agriculture, food forests and hydroponics.