As the world continuously moves forward, so do consumer preferences and famers desire to achieve more with less, thus the debate arises – Aeroponics vs Hydroponics. What are the differences between these advanced irrigation systems? Which growing technique is better? Let’s get into the most exciting features of Aeroponics and Hydroponics to make educated conclusions!

Advanced irrigation: Aeroponics and Hydroponics

The common thought says that plants evolved to grow in soil and therefore that’s the way to grow plants. But when you really think about it, there is a huge variety of plants that grow in water, salty seas and fresh lakes or rivers. There are even plants that grow in unfertile sand or rocks. The adaptability and versatility of plants is quite amazing, and farmers had already noticed that in ancient times. Egyptian farmers diverted fertile river Nile waters to sandy “soil” and fed a whole civilization. Some call it the very first industrial NFT (nutrient flow technique) hydroponic system. Ancient Inca, Maya, and Aztec civilizations pioneered aquaponics with their floating lake gardens.

As science progressed in various fields, so it did in agriculture. Agronomists and plant researchers learned that plants only need light, water, and nutrients. Soil is not necessary for plants to grow properly. Thus, hydroponics was born. The plants are placed in a substrate (perlite, rockwool, coco coir, etc.) and their roots are submerged in water with dissolved fertilizer. Hydroponic growing techniques can be applied anywhere, but most often you’ll find these in greenhouses and vertical farms.

Even though plants grow better and with less resources in hydroponic systems than in soil, basic open field farming practices, the science keeps pushing forward. In early nineties NASA started exploring a new growing technique called Aeroponics. In aeroponic systems plants roots are hanging in aerosol – water nutrient mist. Yield increase surprised everyone.

What is the difference between Aeroponics and Hydroponics?

We already established Aeroponics and Hydroponics are both methods of growing food and medicine without soil. Actually, some even consider aeroponics as a branch of hydroponics as both do not use soil, both aeroponics and hydroponics use nutrient solution (fertilizer dissolved in water) to feed the plants, both use technology (often mechanisms like pumping equipment) to move fertilizer solution right up to the roots of plants.

Nevertheless, there’s a key difference between Aeroponics and Hydroponics:

Hydroponics is a plant growing method when the roots of plants are submerged in liquid solution – water and nutrient mixture. Sometimes, solid mediums such as gravel, sand, and rockwool are used as substitutes for soil to provide support for the roots. You can read more about hydroponics and its variety here.

Aeroponics is a plant growing method when the roots of plants are hanging in water and nutrient aerosol – spray, mist, fog. In most cases experts point out two main types of aeroponics: Low-pressure aeroponics (LPA) and High-pressure aeroponics (HPA). Interestingly, there’s a third type called ultrasonic aeroponics or ultrasonic fogger aeroponics, though quite often it is considered as a new growing technique and people refer to it as Fogponics. You can read more about aeroponics, fogponics and their comparison on our blog.

Hydroponics
aeroponics
Aeroponics

Aerosol vs Liquid

Like mentioned above, in hydroponic systems, roots of the plant are submerged in a liquid – water and nutrient mixture. Which is an “interesting” thing to do when you consider two facts: plants breath through roots too and oxygen solubility in water has a natural limit. Remember that soil is a porous substrate, liquids and gasses can pass through it. So, by submerging the roots, the grower faces the possibility of waterlogging and suffocating the roots. It’s the same as overwatering a plant at home. Oxygen deprived crops result in lower yields or withering.  

Aeroponics is a whole different story – roots of the plants are hanging in air and irrigated with water & nutrient aerosol. We know it sounds crazy, but that’s how orchids grow naturally in rainforest full of fog or next to waterfalls where mist is created by the falling water stream. This advanced irrigation method mimics healthy soil with moisture and gaps full of air and oxygen. More oxygen in the root zone enables faster and better metabolism, stimulating growth and preventing formation of pathogens.

Aeroponically grown plants spend majority (99.98%) of their time hanging in the air and very little (0.02 %) time in direct contact with water nutrient solution that has been converted into aerosol. The atomized water and nutrient mist makes a major contribution to the roots’ efficient oxygenation. The roots are able to absorb oxygen more effectively because of the period spent without water. For contrast, aeroponics has a throughput of 1.5 milliliters per minute, nutrition film technique (NFT) hydroponics has a throughput of 1 liter per minute.

High-pressure Aeroponics

Precision & Manipulation

In hydroponic systems the roots of plants are floating in one big pool – body of water. Any chemical change or adjustment done to the liquid media (water and nutrient mix) shall apply to all plants you like it or not. Most of physical adjustments like air bubblers submerged into the pool will not affect the whole system, those will affect only the plants close to them. So, there’s very little, almost next to no precision in hydroponic systems.

In aeroponic systems, irrigation – the spraying/misting, can be fully controlled on plant by plant basis. The fog can be supplied in precise quantity, quality, and period of time. The physical properties of the mist can also strongly affect the development of the plant. For example, fine mist that has water droplet size of 1 – 10 microns shall provoke secondary root development. So, unlike the hydroponic systems, aeroponic systems can tailor water, fertilizer and gas levels in each growing bed differently, which means that the grower can adjust every nutritional parameter according to individual plant needs and growth stages. This gives the grower the highest level of control over the plants, unlike soil or hydroponic farming.

Root Disease

Root disease is a big problem for hydroponic farmers. Oxygen deprived and liquid water environments are great for fungal and bacterial infections to thrive. The problem is amplified in hydroponics because roots of every plant in the production line are submerged in the same pool. So, if one plant in the production line gets root disease – every plant does. Root disease is deadly to the growers crops and United Nations food and agriculture organization estimates that around 20% of hydroponic crops are lost to it yearly.

That’s not the case in aeroponic technology utilizing farms and greenhouses, because aerosol is an awful carrier of disease. It has been noted by scientists that mist generators, high pressure or ultrasonic, rip apart any cellular organisms too. Also, high amount of oxygen in the aerosol environment prevents root disease since oxygen is toxic to these pathogens. Furthermore, since plant-to-plant contact is restricted in aeroponic and fogponic systems and each aerosol pulse can be sterile, aeroponics and fogponics helps reduce the spread of root disease. Also, if a single plant does get root or any other disease, it may be easily removed from the growing system without upsetting or infecting other plants.

Healthy roots on the left and Diseased roots on the right

Growth, Nutrition, Yields

Plants grow faster and bigger in aeroponic and hydroponic systems than in soil. This has been well known for almost a century now. That doesn’t mean growth is the same in aeroponics and hydroponics – the development pattern is different.

For example, research with sunflower seedlings has shown that hydroponically grown plants tend to grow faster at the beginning. The hypothesis is that hydroponic plants do not need that many roots to take nutrients for the growth at the beginning of growing cycle and aeroponic plants spend more time, nutrition, and energy to develop their roots. Despite that, after a couple of weeks, the aeroponic plants had a well-developed root system and caught up in size to the hydroponic plants. After a couple more weeks, by the time the plants were ready to be harvested, in a way “young adults”, aeroponically grown plants were ~30% bigger than hydroponically grown ones, with the height difference of 10 centimeters.

As we mentioned before, within aeroponic systems plant roots get more oxygen and interval misting of the roots result in better nutrient uptake and faster metabolism. All research shows that plants intake more nutrients in aeroponic systems than in hydroponic systems.

For example, research with lettuce – from seedling to fully grown adult – in both basic aeroponic and industrial hydroponic systems has shown that macronutrient uptake is better in aeroponic equipment. Nitrogen uptake was better in aeroponically grown plants by 1.16%. Phosphorus uptake was better in aeroponically grown plants by 0.43%. Potassium uptake was better in aeroponically grown plants by 0.65%. Calcium uptake was better in aeroponically grown plants by 0.11%. Magnesium uptake was better in aeroponically grown plants by 0.04%.

In terms of yields, there are no clear answers. The main reason being that commercial aeroponics is only in its baby stage. We cannot simply compare hydroponics and aeroponics because both techniques have sub-types of their own. Hydroponics has DWC (deep water culture), NFT (nutrient flow technique), dripping hydroponics, etc. Aeroponics has LPA (low-pressure aeroponics), HPA (high-pressure aeroponics), fogponics (ultrasonic fogger aeroponics). Each sub-type has different yields and quite often performs very differently depending on the crop. Despite all that, the common knowledge says that aeroponics are better for root vegetables and leaf vegetables. The main debate revolves around the fruit vegetables like cucumbers, tomatoes, and peppers. Still, with the rapid pace of innovation, academics believe that hydroponics is a stepping-stone technology and it will soon give way to more efficient and improved growing equipment like aeroponics. You can read more about how Baltic Freya has improved aeroponics here.

I. Aeroponically grown II. Hydroponically grown III. soil grown

Resource Efficiency

Plant growth, nutrition uptake and yields aren’t the only things that matter when you are considering what technology to use for your farm, especially if you are thinking about an industrial farm.

As we already established, hydroponics and aeroponics are a lot more efficient than soil farming. If you would take a look at water consumption: compared to soil farming, hydroponics uses around 80 to 90 percent less water. That seems quite amazing until you see that aeroponics uses around 95% less water than soil farming. When we take a look at fertilizer usage, hydroponics uses from 55 to 85 percent less fertilizer than soil farming and aeroponics outperforms that with at least 85 percent lower fertilizer usage. The third and in some eyes the most important criteria is energy consumption. Hydroponic systems can operate on simple pumps and most of the time do not require a lot of energy. Aeroponic systems tend to rely on more high-tech pumps, ultrasonic aeroponic or fogponic systems require ultrasonic foggers that use a lot of energy. So, energy consumption has to be compared on a very specific basis. Nevertheless, the general thought says that hydroponic systems are more energy efficient than aeroponic ones. Which is why Baltic Freya is working on improving that, you can read more here.

Setup & Maintenance

As you can already guess, the setup costs vary drastically, no matter if you’re going for hydro or aero. But in general, hydroponic systems are a lot cheaper to set up than aeroponic. The main reason for this is that most popular aeroponic systems are the high pressure aeroponics. That means that the grower shall need an enormous amount of high-pressure nozzles that are really expensive. High-pressure pumps required by these systems must be durable, sturdy and lighten your pockets considerably. No pumps are needed if you chose ultrasonic aeroponics or fogponics, which makes it more attractive. Furthermore, no nozzles are needed in these systems and the foggers are relatively cheap. Before you pick a winner, please read about the maintenance problems of these technologies.

High-pressure aeroponics brings the best yield results to the table compared to other two, but this methodology has some serious drawbacks. The biggest issue of HPA systems is clogging. HPA uses high pressure nozzles that have extremely narrow and small spraying holes for water nutrient solution spraying. Naturally, that means – nozzles clog up easily. When they clog up, your crops do not receive water and nutrients that they need. Without moisture the roots will dry up rather quickly and the result shall be death of your plant. If multiple nozzles clog up… Imagine this happening when it‘s almost time for harvesting, your long and hard work could go to waste immediately. Maintenance of these nozzles is a difficult and expensive feat. Also, HPA systems are the most expensive out of the three that we are discussing here.

Fogponic systems have some similar problems to HPA. Fertilizer salt build up clogs ultrasonic misters that fogponics use. Yet again cleaning and maintenance becomes a serious issue. The most important part of the ultrasonic foggers is piezoceramic disk or membrane. These piezoceramics crack over time, and that happens more often than not, then the equipment stops working, doesn’t generate fog and your crops die. Another technical flaw of these foggers is energy inefficiency – 90% of the electricity used is converted into heat, not vibrations. This heat transfers into your nutrient water mix and badly affects plant roots. Moreover, the extremely small size of the water droplets results in high surface tension of the water droplet which makes it hard for the droplet to stick to the roots. Sometimes this fine or dry fog provokes the plant to develop an abnormal amount of secondary roots. So instead of growing it’s leaves, the plant is desperately trying to survive and develops a bunch of useless roots.

Clogged nozzle on the left and New nozzle on the right

Aeroponics vs Hydroponics. Which is better?

Both aeroponics and hydroponics have proven themselves as superior to soil farming in terms of resource efficiency, plant growth and yields. Nevertheless, they come with a fair share of unique flaws, price tags and technical issues.

So, the short answer to which is better is Baltic Freya Fogponics 2.0

Baltic Freya has developed Fogponics 2.0 fog generator that doesn‘t clog. Our mist generators look like nozzles, but require no high pressure. The water and nutrient delivery hole within our fog generators is millimeters wide and it vibrates. We tried to purposely clog it by adding sand, by adding glass shards to the water nutrient solution and we failed to clog it.

Baltic Freya Fogponics 2.0 fog generators do not crack either. Even though our technology is ultrasound based, it doesn’t use piezoceramic plates or membranes that could crack or break. Our mist generators efficient energy design doesn‘t overheat the nutrient solution too. Baltic Freya Fogponics 2.0 fog generators can and do deliver the correct water droplet size of 20-30 microns. But if you wish for a different one – Baltic Freya fog generators are tunable, they can generate water droplets varying from 5 to 60 microns.

Baltic Freya Fogponics 2.0

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