Long hours spent under a scorching Sun, days spent in the countryside bending over a heavy hoe or a spade, grubby hands and aching bones…
That was gardening not long ago. But if you want to look at the future of gardening, and especially urban farming, you will see clean gardens and gardeners surrounded by plants on tables, in tanks and growing strong from pipes, on the floor, at chest level and even above your head.
And all this thanks to hydroponics and aeroponics. So what is the difference between aeroponics and hydroponics?
Aeroponics is a form of hydroponics; both do not use soil, but a nutrient solution to grow plants, but while hydroponics irrigates the roots of the plants with the solution, aeroponics sprays it directly onto the roots.
Growing Without Soil: Hydroponics And Aeroponics
Welcome to the future! And, let me tell you, the future is green! Picture a world where every home, every building, even every office has plants growing in it…
Picture a city where new homes are designed with in-built gardens where families can grow their own vegetables. Picture libraries where books are side by side with plants…
“But aren’t we,” you may ask, “short of land?” You are right – but we don’t need soil to grow plants, and in fact we are even growing them on the International Space Station…
But how? Simply, with hydroponics and the even more futuristic looking aeroponic gardening.
From a purely aesthetic point of view, aeroponics has that sleek look that screams out, “Innovation!” On the other hand, most people still associate hydroponics with a less refined appearance.
But even this is not accurate; there are hydroponic kits and systems that look like they come from the set of a sci-fi movie.
With names worthy of equipment you would find on USS Enterprise, however, the key concepts of these two gardening methods are very simple.
What Is The Difference Between Hydroponics And Aeroponics?
Aeroponics is actually a “sub sector” of hydroponics, but the two are often seen as two competing fields. Both have similar principles, however:
However there is one key difference between the two:
Hydroponics brings the nutrient solution (water and nutrients) to the roots of the plants, while aeroponics sprays droplets of the solution onto the roots of the plants.
The term “hydroponics” comes from two Ancient Greek words, “hydros” (water) and “ponos” (work, labor), while the word “aeroponics” from “aer” (air) and again “ponos”. So, hydroponics means “labor of water” while aeroponics “labor of air”.
How Was Aeroponics Invented?
In the early phases of the history and development of hydroponics, researchers faced an important problem to solve: roots need air, as they need to breathe as well as absorb water and nutrients. The first response was to use an air pump to oxygenate the nutrient solution.
That may look like it would do the trick, but it turned out to be an inadequate solution. An air pump may provide some aeration to the roots, but it is often insufficient and uneven.
Think about it; if you have a large grow tanks, where would you put the air stone of the pump? If you put it in the middle, the plants around the sides will get little air. If you put it on one side, the plants at the other end would get nigh on nothing at all…
So, researchers came up with new methods, like ebb and flow, to solve this problem. Among these, some started looking at spraying droplets of water onto the roots as a solution.
This met with studies already afoot where biologists where testing spraying nutrients on roots to test their growth. So, in 1957 the Dutch biologist Frits Warmolt Went coined the term “hydroponics” and by 1983 the first aeroponic kits were available on the market.
That, however, was the result of a long research effort that started in 1911, when Russian exobiologist Vladimir Artsikhovski published a study entitled “On Air Plant Cultures”. What’s exobiology? It’s the study of life on other planets… And we have come to full sci-fi circle…
Hydroponics And Aeroponics Vs. Soil Gardening
Closing the history “corner”, the big question is, how do hydroponics and aeroponics compare with soil gardening? They are far better:
So, we can easily deselect soil gardening from our friendly competition. But how about the two finalists? Which is better? Hydroponics or aeroponics?
Hydroponics And Aeroponics – Plant Growth
Plants grow bigger and faster with hydroponics and aeroponics than with soil farming. This was one of those realizations that changed the world, and it has been an established fact for almost 80 years now.
But plant growth has a differ
What does all this mean in the end? If these studies are confirmed, because the first six weeks are, for most annuals, the time where growth is faster, you will end up with bigger plants if you use aeroponics.
In terms of plant growth, aeroponics is a clear winner then!
Nutrient Absorption In Hydroponics And Aeroponics
When you eat and drink well, you feel well. The same applies to plants. All research shows that plants absorb more nutrients with aeroponics than hydroponics.
In fact, uptake of macronutrients for example, shows a clear picture in a study on lettuce:
This explains why plants grow faster with aeroponics, but it also means that you will have less nutrient waste, which, in the long run, means saving money.
Aeroponics And Hydroponics Yield Comparison
Size is not all though, and big plants do not necessarily mean bigger crops, especially if we are talking about fruit vegetables like tomatoes, peppers and cucumbers. But let’s not beat about the bush: which gives bigger yields?
But don’t jump the gun… That was a small research and they used an ultrasonic fogger, which does not come for free.
In terms of yield, at the moment we can only suspend judgment; still, aeroponic looking like it may come out as a winner some time soon.
Closed And Open Environments In Hydroponics And Aeroponics
Now I’ll let you in on a very important debate in the futuristic world of hydroculture (hydroponics, aeroponics and aquaponics); is it better to keep the roots of plants in a closed or open environment (e.g. a grow tank)?
So far, data show that closed environments are better:
Not all hydroponic systems have closed grow tanks, while aeroponics only works if the aeroponic chamber is closed. This works as a “vapor room” (they are droplets technically) where the roots can feed.
You will place your plants in holes with flexible rubber collars leaving the roots to dangle inside the aeroponic chamber and absorb the nutrients sprinkled in there.
Still, growth and yield are not everything when you need to choose which system to set up, especially if you want to do it professionally or in any case you are aware of costs.
Both are more efficient than soil gardening, but one method is more efficient than the other when it comes to best use of resources. And, you guessed, it is once again aquaponics. In fact, compared to soil gardening:
In terms of irrigation water savings, hydroponics saves you between 80% and 90% of water compared to soil gardening (depending on the system you use). But aeroponics saves you 95%!
When it comes to saving on fertilizer, hydroponics ranges between 55% and 85% (again depending on the system) and aeroponics is steady at the very top of this range: 85%.
If you want a productivity increase comparison, a study on tomato crops shows that hydroponics produces between 100% and 250% more than soil farming (still between twice and more than three times as much) but aeroponics comes out punching the air (little pun) with 300% more.
Therefore, in terms of running costs, aeroponics is in the long run cheaper than hydroponics.
Having said this, the main cost of aeroponics may be the electricity used by the pump; because there are many pumps, and some gardeners may get carried away with the quality and power of the pump, the running cost may grow fast if you go down the “techie” route.
Differences In Setting Up Costs
Here, I am sorry, is where aeroponics becomes less attractive. Hydroponics on the whole appeals if you don’t want to have high starting costs when setting up the garden. Why?
There are many hydroponic methods, and some are as cheap as the old jug your aunt gave as a Christmas present which you left in the cupboard to gather dust.
You can easily build a hydroponic garden yourself; with basic plumbing skills and cheap and easy to buy pumps and a few meters (pH, thermometer, EC gauge) you can have a small garden up and running in a good afternoon spent playing your kids.
It is much harder to DIY an aeroponic garden; most people will need to rely on a ready-made kit.
There are fairly cheap aeroponic kits on the market though; but if, for example, you have a greenhouse and you have decided to turn it into a farm, that will have a considerable impact in your pockets.
If you want to stay on the cheap, you can instead buy some pipes, tanks, pumps etc. and build a hydroponic garden tailored for your space.
In this all-decisive category, hydroponics is the clear winner. Maybe even more than a winner, it may be the only affordable solution for many of us…
A Big Difference Between Hydroponics And Aeroponics: The Pump
Coming to a technical point, there is a difference in what you want from the pump of you choose with hydroponics rather than aeroponics. Let me explain…
With hydroponics, what matters is that you get enough nutrient solution to the roots of your plants.
On the other hand, with aeroponics you have to add a factor: you need to spray the nutrient solution, and this is why you need a pump with the right pressure.
This means that:
With hydroponics, you need to check that the GPH (gallons per hour) capacity of your pump is enough to fill your grow tank or provide enough nutrient solution.
With aeroponics, you need to make sure that your pump has adequate PSI (pounds per square inch); that is the pressure of the pump on the nutrient solution.
You may think that this is quickly sorted; just get the right PSI for your garden and everything will be fine.
In a way, that’s true if you buy a kit, but if you want to set up a professional garden, things become a bit more complicated.
The Many Variables Of PSI In Pumps For Aeroponics
If you aware just deciding which kit to buy to have a fresh salad on your table, you may skip this and jump to the next section.
But if you are looking around for information because you want to have a big, professional aeroponic garden, this section will come in handy.
The point is that the PSI of the pump does not necessarily translate into the PSI you get from your nozzles.
Why? Put simply, it is pressure, and there are factors that will change it from the moment it leaves the pump to when it reaches your plants’ roots.
Blow out a candle a few inches from your nose and one on the other side of the room…
The concept is the same. Or blow air through a straw and then try again without it; did you notice that it goes out stronger with the straw?
In fact, the pressure you get at the nozzles will depend on:
The elevation differential: whether the pipe goes up, down, or stays at the same level and how much.
Even the material of your pipe does make a difference.
This is not to put you off. Even for a fair size garden, you will only need to tweak the system a bit, maybe getting smaller pipes or better nozzles to get good results.
However, if you have a big, professional garden in mind, you will need to calculate these factors.
Luckily, there are PSI calculators online that you can use, so, you won’t need to take your old physics textbook out and try to apply one of those alien looking formulas that gave us nightmares at school.
Can I Use A Growing Medium With Aeroponics?
Using a growing medium like coconut coir, expanded clay or vermiculite has marked a major step in hydroponics; it has allowed us to have a constant supply of nutrients while not having the roots in the solution all the time. But if you were thinking about using it with aeroponics, think again… Using a growing medium with aeroponics means putting an obstacle between the roots and the source of nutrients.
Just picture it: you spray a liquid onto a mesh pot with lots of pebbles; what happens to the solution? It can only permeate the outer pebbles and it will find it hard to reach the roots.
In a way, though, this is another saving, if a small one…
Differences In Irrigation Cycles
If you come to this article with some knowledge of hydroponics, you will know that some systems (ebb and flow, even the drip system in many cases) have an irrigation cycle; you send the nutrients to the plants at regular intervals.
This is to feed and water the plants while allowing them plenty of time to oxygenate the roots as well.
Not all hydroponic systems use cycles, deep water culture, wick system and Kratky don’t use it. Nor do all aeroponic systems.
In fact there are two main aeroponic systems:
Low pressure aeroponics (LPA) sends droplets of water under low pressure to the roots. This system runs continuously in most cases.
High pressure aeroponics (HPA), instead, manages to send droplets to the roots at string bit intermittent bursts.
HPA is more efficient than LPA, but also more complex; you will need to regulate the cycles according to the weather and temperature, the crops and even the air humidity.
In ebb and flow hydroponics, irrigation varies too, but it is between 5 and 15 minutes every 2 hours during the day and once or twice at night (if it is very hot and dry).
Here again, it depends on the heat, crop and even if you use a growing medium, which takes slightly longer to absorb the nutrients than bare roots.
In HPA, on the other hand, these cycles are shorter and more frequent. This too depends on the crop, on the life phase of your plants, temperature etc. However, the average is 5 seconds every 5 minutes.
Don’t worry though; in both cases, you will not get a sore wrist switching on and off the pump all the time, all you need to do is set a timer…
Which System Is Better For Your Plans’ Health? Hydroponics Or Aeroponics?
With many hydroponic systems, plants share the water and nutrient source; unless you have plants in individual grow tanks (like with the Dutch bucket system), this means that the nutrient solution may spread disease from plant to plant. Conversely, with aeroponics, the droplets go straight from the nozzles to the individual plants; this reduces the risk of spreading disease.
Both methods, though, give much healthier plants than soil gardening.
How About Maintenance?
Your path to the green urban world of the future is now at a road fork; on the one hand, you have an easy but still rewarding life, on the other a harder but more productive one…
Aeroponics needs continuous checks and constant monitoring; hydroponics is far less demanding from this point of view.
All aeroponic systems are fully dependent on electricity; not all hydroponic systems are.
Not only, but because the cycles of HPA are fast and short, any electrical failure, even if short, may have serious consequences.
Many aeroponic experts say that keeping the humidity and heat conditions steady in the aeroponic chamber can be a challenge.
The problem is worse with small chambers, while bigger ones have steadier conditions.
Thus, on the whole, if you want an easy life, hydroponics is a much better option.
Indoors And Outdoors
Unfortunately, here you have no choice. Hydroponic systems can be adapted to outdoor spaces, while aeroponics is mostly suitable for indoor spaces.
If you don’t have space in your home, a garage, or even a greenhouse, hydroponics is your only option.
Back To The Future
Hydroponics is a well established field, there may be new developments, but if they come, they will do so mainly from the invention of new systems.
We have seen new solutions come in the past decades: first it was the deep water culture, then the wick system, then we went ebbing and flowing, then dripping nutrients…
Then… Aeroponics came along… And here we found that varying the pressure, the cycles, even the shape of the aeroponic chamber, we achieved major improvements, just by “tweaking a bit” with the basic model.
Now there are ultrasonic foggers, high pressure systems, we can even envisage the use of magnetized water easily applied to aeroponics…
On balance, we can see aeroponics developing fast and easily in the years to come, and this will shape our future, that of our families, and that of the whole world, even reshaping the economy perhaps, and bringing sustainability into every urban household.
The Future Is Here, But Which Is Better, Hydroponics Or Aeroponics?
Both aeroponics and hydroponics give better results and yield than soil gardening and are suitable for indoor and urban spaces, but aeroponics gives bigger yields, healthier plants, has lower running costs and looks set for future developments, while hydroponics is easier to set up and manage and is suitable for most people and crops, both indoors and outdoors, while aeroponics is mainly suitable for indoor gardening.
“But which one is actually better,” you may ask? On the whole, aeroponics is better if you want a high-tech system and you wish to specialize in forward-looking gardening methods, but also if you have a good budget to start with and you have time and know-how for its maintenance.
If, on the other hand, you want an easier and cheaper to set up system, which is low maintenance and with many tried and tested techniques that suit a wide range of crops, then hydroponics is what’s best for you.
Fast forward a few years now… and look around you… Your home is full of plants, strawberries, lettuce, basil plants with their fragrance fill your living room; even that corner of your bathroom that was annoyingly empty for many years now has a tower with green leaves on it…
Your children have taken up a new hobby that takes them back to our collective past: growing plants to be self sufficient.
And, whether you choose hydroponics or aeroponics, you will be able to look at your children in the eyes and say, “You know, sunshine, I was one of the pioneers of all this green new world…”
Wasn’t it all worth it?
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.