Hydroponic growing has been around for decades, but with its capability to produce lots of food in a small space, it’s really caught on with the mainstream public in the last several years. As hydroponics has grown in popularity, so has its lesser-known cousin- aeroponics!
What’s the difference in aeroponics vs hydroponics? Hydroponics immerses a plant’s root system in nutrient-enriched water that eliminates the need for standard soil. In aeroponics, the plant’s roots are suspended in air and sprayed with nutrient solution. Hydroponic systems tend to be cheaper to build and easier to manage, but aeroponics uses less resources and tends to produce a better harvest.
Today, you’ll learn the key differences that set these two growing systems apart, some general cost comparisons and what to expect in terms of maintenance. By the end of the post, we hope you’ll have determined which system might be a better fit for you and some ideas on getting started.
Let’s dive in!
What are Aeroponics and Hydroponics?
First of all, it’s important to note that there are six broad categories under the larger umbrella of “hydroponics,” with aeroponics being just one of them. Here they are:
- Wick hydroponics
- Drip hydroponics
- Deep water culture (abbreviated DWC)
- Ebb and flow (also called flood and drain)
- Nutrient film technique (abbreviated NFT)
Although the exact method varies between the 6 categories, the one thing they all have in common is that they are water-based growing systems. Each technique uses water, not soil, to carry necessary nutrients to a plant’s root system.
You’ll see this in much more detail in the next section where we cover how each system works.
Aeroponics and hydroponics are fantastic alternatives to soil-based agriculture for many reasons, including these:
- You don’t have to own land for aeroponics and hydroponics. A countertop, spare room or garage works great.
- Perfect for both urban and rural settings.
- You can grow indoors with grow lights and a grow tent or outdoors in a suitable area.
- You can ensure your plants get the exact nutrients they need in the proper amounts.
- Instead of building soil fertility over years, you can set up a productive hydroponic or aeroponic system in days.
- Almost any plant can thrive in a hydroponic system. (Although some, like melons and root vegetables, are harder to care for and typically don’t produce a very impressive harvest.)
In this article, we’ll refer to the first 5 hydroponics categories on our list collectively as “hydroponics.” Then we’ll be setting up our contrast between them as a group and aeroponics specifically.
Fun fact: Even though hydroponic growing has a futuristic feel to it, it’s actually been in use for quite some time. Hieroglyphics depict ancient Egyptians farming in the waters of the Nile, Marco Polo recorded accounts of the Chinese using floating gardens, and farmers in the Aztec Empire grew crops on floating islands called chinampas.
So you can be a part of history and the future at the same time!Source: Medium
Differences in Hydroponic and Aeroponic Systems
There are 6 main differences between a hydroponic system and an aeroponic one:
- Water delivery method
- Grow media
- Oxygen exposure
- Air pump
- Starting seeds
- Vulnerability to power outages
Let’s look at each one in detail:
1. Water Delivery Method
The most crucial difference between hydroponics and aeroponics is how they deliver water and nutrients to your plants’ root system.
Hydroponic systems work by submerging the roots in water, either continuously or on an intermittent automated schedule. Here’s a graphic that shows a deep water culture set-up, which is probably the most popular hydroponic technique:
The plant’s roots are suspended in a nutrient-rich solution with an air pump/air stone combo that supplies the necessary oxygen for the plants to absorb. In this method, you’ll have to maintain a high water level to sustain your plants, and the water provides all the nutrition and oxygen the plants need.
And here is an aeroponic system:
As opposed to having their roots submerged in water, the roots in an aeroponic system are suspended in the air and sprayed continuously with nutrient solution. This constant exposure to the air allows the plants to absorb maximum oxygen, and the sprayer keeps the roots hydrated and nourished.
2. Grow Media
Hydroponic systems always use net cups filled with grow media to anchor the plants in the system, much like soil anchors plants in a traditional garden. Some of the most common hydroponic grow media include:
- Expanded clay pebbles (also known as Hydroton pebbles or Leca)
- Rice hulls
- Rockwool cubes
- Coco coir
- Peat moss
These are all inert substances, meaning that they don’t provide any nutrition for the plants (they get all the nutrients they need from the water). Instead, grow media simply provides stability during your plant’s life cycle.
In aeroponic systems, there’s a common misconception about grow media. Many people say that you can’t use grow media with an aeroponic system and instead, you must use a special foam piece that functions as a collar for your plant.
The grow media itself does nothing to add nutritional value to your plant, and you could even use materials like marbles or Styrofoam chunks if you wanted. But aeroponic growers who do use grow media feel that it’s provides better plant support than a collar.
In the aeroponic graphic above, you’ll see that you have the option to use a specialized foam collar or a net cup filled with grow media to support your plant.
Here’s what a foam collar looks like in real life:
Slide the main stem of your plant into the collar through the slit, and settle the collar into the aeroponic system. The collar holds your plant securely but gently in place while it grows.
If you’re unsure which way’s best to secure your plant in an aeroponics system, here’s a look at the pros and cons to both:
- Collars are reusable for a few growth cycles if cleaned properly between uses, so they cut down on cost and waste
- Moving your plant into or out of the aeroponic system is an easy process that doesn’t disturb the root system, even for larger plants
- The collar fits snugly into the aeroponic system, almost eliminating water loss through evaporation
- May provide less plant stability than media
- Anchors plants securely in the aeroponic system
- You can start your seeds in the net cup/media, then easily transfer the whole cup into the system once the roots are long enough
- As long as your plants were healthy during their entire life cycle, you can sterilize/reuse some types of grow media
- Not every material is reusable
- Allows water to escape the system through evaporation
So it’s nice that aeroponics offers the choice, and you can even experiment with both to see which method gives you the best results.
3. Oxygen Exposure
Hydroponics suspends the plant above a water reservoir and keeps the roots mostly or completely submerged. This is simple and generally very efficient, but it can be difficult to make sure enough oxygen reaches the roots.
Many growers place an air stone to the bottom of the reservoir to create a constant stream of bubbles and oxygenate the roots. Also, some growers regularly add low-strength hydrogen peroxide to their reservoirs to help increase the amount of dissolved oxygen in the water.
In aeroponics, the plants are suspended above a mostly-empty chamber instead of a large water reservoir. The plants get their nutrition from the nutrient water spray, but they’re primarily surrounded by air.
This continual air exposure gives the plants ample opportunity to absorb oxygen freely, which leads to faster growth and better yields.
4. Air Pump
Even though an air pump in both hydroponics and aeroponics does the same basic thing (pumps air), the way you use the pump is quite different:
Hydroponics uses an air pump to push air through an air stone to release oxygen-rich bubbles into the nutrient-solution reservoir. If you’ve ever seen a fish tank with a bubbler sending up a shower of tiny bubbles, you’ve seen what an air pump in a hydroponic system does.
This is a simpler setup than that of aeroponics, and if the pump fails, the plants won’t be immediately affected because their roots are already in water.
Plus, if you use a passive hydroponic technique, like wick hydroponics or the Kratky method, you don’t need an air pump at all.
Aeroponics uses an air pump to generate and spray a nutrient-rich mist through nozzles and onto your plants’ roots. The stronger the air pump, the finer the spray, and the better the system works.
Some types of aeroponic systems require very precise PSI from the air pump, requiring some troubleshooting and frequent monitoring on the grower’s part.
The entire aeroponic system essentially hangs on the use of an air pump. And one risk of growing aeroponically is that if your pump fails, the water won’t reach the roots of the plants, and they will quickly wither and die without outside intervention.
5. Starting Seeds
Starting seeds in a hydroponic system is an easy process, but you’ll have to use a two-step method to start seeds for aeroponics.
With hydroponics, you can start seeds directly in the net cups your plants will spend their entire lives in. Growers can easily keep the media in the net pot moist, either with a drip system or by manually watering the seedlings.
Once the seedling has rootlets long enough to reach the water in the reservoir below, the hydroponic system takes over.
Generally, aeroponics growers will start their seeds in a separate, dedicated area, and then transplant them into the aeroponic frame once they have developed some roots.
While this is not a difficult process, it does require you to have a separate area set up for starting new seeds.
6. Vulnerability to Power Outages
Losing power is a problem for hydroponic growers, but it quickly becomes a nightmare for those with an aeroponic system.
Hydroponics have your plants’ roots at least partially in the water, so your plants won’t dry out and suffer damage immediately. While long-term loss of electricity will harm your plants, an outage that lasts a few hours will probably not cause any problems.
On the other hand, plants in an aeroponic system rely fully on the nutrient spray for life-giving moisture and nutrition. When that gets disrupted by a power outage, your plants will feel the effects right away.
If you live in an area that’s prone to losing electricity, this is something to consider.
Comparing the Yield in Aeroponics and Hydroponics
According to research firm Markets to Markets, hydroponic growing methods as a group typically produce a harvest that’s 20% to 25% greater than plants grown in a comparable area of soil. And they also accomplish that feat with approximately 80% less water consumption, as Trees.com reports.
So it’s pretty evident that hydroponics/aeroponics are superior in their efficiency compared to growing in soil.
But is there a significant difference between aeroponic vs hydroponic yields? Let’s find out:
How Oxygen Exposure Can Lead to Increased Yields
We’ve already established that oxygenation is an essential part of plant health because it’s part of the process of cell exchange.
But what does oxygen actually do for your plants? Why is it so critical? Because one of the key roles of oxygen for a plant is to facilitate nutrient absorption.
Even if you’ve filled your hydroponic system with the perfect blend of nutrients to meet your plant’s every need, the roots won’t be able to absorb these nutrients without the help of oxygen.
And that’s really the basic premise of aeroponics:
- More oxygen exposure = More oxygen absorption
- More oxygen absorption = Better plant health and production
A recent study published in the American Scientific Research Journal for Engineering, Technology and Sciences states that the high oxygen exposure in aeroponics results in plants that are stronger and may be higher in nutrition.
Also, because each plant is sprayed individually rather than immersed in the same reservoir, aeroponics has less chance of disease spreading between plants. And as any grower knows, plant disease is a surefire way to lose some or all of your crop.
While the actual harvest you get may or may not be much different in hydroponics vs aeroponics, aeroponics does win the match-up in terms of plant health, nutritional content and disease resistance.
How Much Does It Cost to Set Up Aeroponics Vs Hydroponics
If aeroponics is more productive than hydroponics, why doesn’t everyone do it?
Basically, aeroponic systems are more expensive and more work than hydroponics.
Let’s look at the expense issue here (we’ll cover the maintenance in the next section):
Basic Hydroponic and Aeroponic Components
You can set up a simple but highly productive hydroponic system with:
- An air pump: roughly $15-$50
- A handful of aquarium air stones: roughly $10-$20
- Plastic tubing: roughly $10-$20
- A few food grade 5-gallon buckets: roughly $8-$15 per bucket (you may be able to get these for less money or free from food service establishments)
On the other hand, aeroponic setups are much more involved. You’ll need:
- High- or low-pressure air pump: roughly $25-$100+
- Plastic tubing: roughly $10-$20
- Reservoir: price varies widely based on size
- Fine-spray mister heads: roughly $10-$20
- Cycle timer: roughly $15-$30
- Solenoid valves (Wikipedia has a good definition of what these are): roughly $15-$30
So it’s not hard to see that the initial costs of setting up an aeroponic system are higher than those for a basic hydroponic one.
Estimated Actual Hydroponics and Aeroponics Building Costs
To give you an idea of the actual monetary value here, we asked Brody Hall, a certified horticulturalist and co-founder of The Indoor Nursery for his cost estimates. Here’s what he had to say:
- Commercially: 7-12K per unit
- DIY: $100-500
- Commercially: $300-1000 per unit
- DIY: $100-200
So for either system, plan to spend at least $100 for your DIY build.
But keep in mind that your $100 will cover a very basic aeroponic set-up while that same amount will produce a pretty solid hydroponic one. So the value you’re getting for your investment is definitely something to consider.
However, building a system yourself isn’t your only option. There are pre-made aeroponic systems on the market in a variety of sizes.
Aerogarden is a popular brand that uses low-pressure aeroponics to nourish your plants, and Click and Grow uses a passive hydroponics system. (Use our special promo code “SEEDS10” if purchasing anything on the Click & Grow site to get 10% off your purchase!) Both systems also come with attached grow lights, so you can place your garden anywhere you like!
Long-Term Hydroponic and Aeroponic System Costs
Plus, for both systems, there are some long-term overhead costs to factor in:
- Nutrient concentrates
- Water testing supplies
- Replacement parts
- Cleaning supplies
Many people start by creating a simple hydroponic system at home and use their experience to determine if they want to try aeroponics. Also, your experience with hydroponics can be a good guide to how much they want to spend on a potential aeroponic build.
RELATED: To get some ideas on how that money gets put to use, visit our compilation post of DIY hydroponic building plans. You’ll find instructional videos and information on a variety of hydroponic and aeroponic systems you can construct yourself.
Maintenance Needs for Aeroponics vs Hydroponics
Once you have your system in place, what kind of upkeep tasks are you looking at? Here’s a rundown of what you can expect in terms of hydroponic and aeroponic system maintenance:
- Frequent water testing
- Ensure the spray nozzles are free of clogs
- Disinfection and cleaning
- System component inspection
- Water testing
- Maintain proper water levels
- Disinfecting and cleaning
- System component inspection
Water testing. The biggest maintenance item in an aeroponic system is testing the water for nutrient content and pH balance. Ideally, you should test your water daily.
Because these systems are constantly circulating a small volume of water, the nutrient content and pH number will fluctuate frequently. To stay ahead of any potential problems snowballing into serious imbalances, you’ll need to keep a close eye on your system’s numbers.
If the numbers do get out of hand, you’ll have to stop the circulation, empty the system, and start all over again.
To do your testing, you can use either test strips or a digital meter. Test strips are the less expensive option, but the convenience and precision of a meter is hard to beat.
Ensure the spray nozzles are free of clogs. Another crucial task is to inspect the roots for dehydration and the nozzles for clogs.
Mineral deposits or scaling can block the nozzles and deprive the roots of water, which dries them out. Also, nozzles can sometimes get knocked out of position and need to be adjusted before their target roots get too crispy.
Disinfection and cleaning. Water-based growing systems are susceptible to algae growth, so you’ll have to perform routine cleaning to keep things safe.
Once a month is typically a good aeroponics cleaning schedule, and food-grade hydrogen peroxide, bleach or isopropyl alcohol are excellent cleaners.
Here is a video from Zip Grow that outlines the basic supplies and techniques for keeping an aeroponic or hydroponic system clean:
Inspect system components. An aeroponic system involves finely-tuned air pressure and water flow, so you’ll have to check your system regularly to spot any loose parts or those that are out of calibration.
Water testing. Hydroponic systems also need to be tested for nutrient and pH imbalances. But because hydroponics uses a larger volume of water than aeroponics, you’ve got a little more room for error before an imbalance does much damage to your plants.
Plan to test your water every 3 days, and always test any fresh water before you add it to the system.
Maintain proper water levels. It’s also important to keep an eye on the water level within your reservoir. Remember, hydroponics is an open system, so moisture can escape through the net pots/grow media. So you’ll also need to make sure to do regular top-offs of water in the reservoirs to maintain the necessary water level and overall volume.
Disinfection and cleaning. Another task for maintaining your hydroponic garden is routine disinfecting and water changes. Clean your hydroponic system with food-grade hydrogen peroxide, bleach or isopropyl alcohol, and change out the nutrient water with a fresh batch.
Plan on scheduling this upkeep for every 2 to 3 weeks. (See the video above for more details.)
System component inspection. And of course, it’s also important to inspect your pumps, tubing, valves, and any other mechanical parts or connections for wear, tear, or degradation–and to check for leaks!
What are the Environmental Effects of Aeroponics and Hydroponics?
Aeroponic and hydroponic grow systems are widely touted as sustainable growing solutions, but it’s important to fact-check that assumption. Based on the resources and inputs involved, what is the environmental impact of aeroponics vs hydroponics?
We’ll break it down into three categories:
- Water usage
- Energy consumption
1. Water Usage
Calculating water usage in aeroponics vs hydroponics in a head-to-head comparison is tricky, partly due to the different mechanics of the systems involved.
Aeroponic air pumps are measured in pounds per square inch (PSI), while hydroponic pumps are gallons per hour (GPH).
That being said, aeroponic growing generally results in less water lost in evaporation. This is especially true if you use a plant collar instead of grow media since the collar doesn’t allow moisture to escape. Also, these systems can run for a long time without needing too much fresh water to be added.
Hydroponic systems, on the other, have larger reservoirs that need to be regularly emptied and replaced. And the media-filled net pots also allow for more water loss through evaporation.
So, on balance, aeroponics tends to use less water than hydroponics.
Plastic is seemingly everywhere in our modern life, but we all want to use less for our own sake and to keep it out of the global ecosystem.
While both aeroponic and hydroponic systems have a heavy reliance on plastic parts, aeroponics has a slight edge over hydroponics.
This is because many hydroponic systems require large reservoirs and multiple long pieces of tubing. That means that hydroponic systems have a higher overall plastic consumption than aeroponic systems, which tend to be smaller overall.
3. Energy Consumption
Both hydroponic and aeroponic systems rely on climate control and mechanically circulated water, and they constantly consume energy at a roughly equal rate. Even though neither system uses a ton of energy at once, they each use a fair amount just because they run around the clock.
The exception to this are passive hydroponic systems (wick hydroponics and the Kratky method) which don’t require electricity at all. But both of these techniques are limited in terms of which plants you can grow and how many.
Because some hydroponic methods don’t consume any electricity, we’re going to give the win to hydroponics here.
NOTE: Another eco-friendly option is investing in a renewable energy source, like solar panels. And for a hydroponics systems, a solar-powered air pump could be a nice option if you live in a sunny area.
Expert Opinion: Is Aeroponics or Hydroponics Better for Most People?
We wanted to find out what the general consensus is about whether an aeroponic system or a hydroponic system is the best choice for the average grower. So we asked some fellow gardening experts for their opinion, and why they felt that way. Here’s what they had to say:
Zach Vandergraaf of Love From Our Backyard:
“For almost every situation, I’d recommend starting with hydroponics. There are a lot more resources out there to help you, and it’s more forgiving with plant growth. With aeroponics, if something breaks down, your plants are in danger almost right away.”
Stephen Webb of Garden’s Whisper:
“Most people are better off using hydroponics due to its lower cost. While aeroponics is extremely beneficial in plant growth rates, it requires a more complex setup and can be very expensive to set up.”
And we tend to agree with the experts listed above: Hydroponics is a perfect way to jump into the world of water-based growing, particularly with passive techniques (Kratky, wick hydroponics) or a simple DWC system.
Many of the same management techniques used in hydroponics also apply to aeroponics, but a hydro system allows more room for trial and error as you learn. Plus, most hydroponic systems cost less to get started and are much easier to build.
Once you’ve mastered the basics of hydroponic growing, you’ll have experience to fall back on when you decide to tackle the more advanced aeroponic systems. And that can only increase your chances of success!
Frequently Asked Questions about Aeroponics vs Hydroponics
Hydroponics and aeroponics both have their advantages and drawbacks. But they are both great ways for detail-oriented, mechanically-minded gardeners to grow food year-round!
Do you have any more questions about either of these two systems? Or maybe you’ve tried one or the other and picked up some knowledge of your own. Either way, your thoughts can help others learn too, so we’d love to hear from you in the comments!