At first, comparing aquaponics vs hydroponics may seem like you’re looking at two things that are nearly the same, and it’s true that the systems do share some common features. But there are several significant differences that make aquaponics and hydroponics two separate techniques.
Aquaponics is a system of growing fish and plants together in a balanced ecosystem where the fish waste is converted into nutrients for the plants and the plants naturally filter the fish water. Hydroponics is a closed-loop, soilless growing technique that relies on fertilizer-enriched water to provide plants with the nutrition and pH balance they need.
I’ve personally used a couple of different small hydroponic gardens, which I found to be very easy and fun. I’ve also spent time learning about and observing a friend’s truly impressive large-scale aquaponic system. Today, you’ll learn about the differences in both systems and why each one has its pros and cons.
Let’s get started!
Aquaponics vs Hydroponics Quick View
Requires more space
Needs less space
Up to 18 months for full production
Up to 1 month for full production
Best for leafy green, lettuce and herbs
Reliance on Electricity
Check water every 7 days, water changes usually not needed
Check water every 1-3 days, change water every 2-4 weeks
How Aquaponic and Hydroponic Systems Work
Before we dive into the differences between the two growing systems, let’s take a quick look at how each one operates:
What is Hydroponics?
In hydroponics, the grower adds fertilizer to a water reservoir, and the system circulates this nutrient-rich water to each plant constantly or intermittently. The plants get their nutrients delivered directly, and the roots also have better oxygen exposure compared to those grown in soil.
Zach VanderGraaf, hydroponic grower and blogger at Love From Our Backyard, likes hydroponics for several reasons. “It’s great because it’s simple but effective at helping plants grow faster, larger, and cheaper than traditional soil-based systems. The downside is how you need to check the water all the time to make sure there’s enough, and you need to change the water to provide enough nutrients.”
Here’s an example of what one type of hydroponic growing system looks like:
Hydroponic upkeep also requires maintaining the water’s pH level. Typically, that value should stay on the acidic side, somewhere between 5.5 and 6.5. This allows nutrients to be maximally available to plants.
And keep in mind that we’re barely scratching the surface here when it comes to hydroponics. To learn more, stop by the Pure Greens website and check out this Ultimate Guide to Hydroponics!
I’ve done some small-scale hydroponic growing. In my experience, it’s fun and pretty amazing to watch plants thrive without any soil involved. I had both gardens in my basement, so it was nice to be able to convert that space into a mid-winter growing area.
What is Aquaponics?
Aquaponics, on the other hand, is the blending of aquaculture (farming fish), with hydroponics.
“The fish add nutrients to the water through their waste, scaling, and natural bacterium. It’s great because it’s more natural and requires less ‘added nutrients’,” Zach says. “You also get to keep (or eat) the fish. Its biggest downside is the added cost and responsibility of keeping the fish on top of the plants.”
Instead of using fertilizers to support plant growth, aquaponic systems rely on the symbiotic relationship between fish, bacteria, and plants to farm both plants and fish.
Here’s the basic breakdown:
- Bacteria consume fish excrement, which helps keep the water clean for the fish.
- The bacteria also convert the waste’s ammonia into nitrate, which is a usable form of plant food.
- As the plants take up this nitrified nutrition, they are actively cleaning the fish’s water.
The first time I saw an aquaponic system was a few years before I had a personal interest in gardening. This set-up belonged to a family friend, and as I now realize, it was genius. The system was an enclosed greenhouse attached to the family’s main house. There were several upper growing trays and a large lower reservoir filled with native fish that were adapted to our cold northern winters, so the tank only needed minimal heating.
I didn’t fully understand the concepts behind aquaponics then, but I remember being impressed. And now that I know much more about aquaponics, I’m even more blown away.
Here’s a visual to give you a better idea of how aquaponics works:
This cycle keeps the fish fresh and healthy while also providing nutrients for plant growth, leading to one of the coolest benefits of aquaponic growing: dual harvest.
If you choose edible fish such as tilapia, catfish, trout, or shrimp to grow in your aquaponic system, you can harvest them. But keep in mind that these fish require large aquatic spaces to grow, so these are only good options if your aquaponic tank is on the bigger side.
Differences Between Aquaponics vs Hydroponics
So know that you know the basic operating principles of hydroponic and aquaponic farming, let’s look at what sets these systems apart:
- Production timeframe
- Plant choices
- Organic certification and sustainability
- Routine upkeep
Let’s break each of these down into more detail.
Aquaponic systems have a higher start-up cost, often by a significant amount. According to Emily Barbosa Fernandes, a small-space gardener and consultant at HouseGrail, expect to invest about $1400 for a backyard-friendly aquaponics system. If you’re considering a large-scale operation, the set-up costs may reach about $20,000.
In general, aquaponic systems tend to be larger than hydroponic ones, owing primarily to the fact that you need additional space for your fish tank. Even with two plant growing beds that are the same size, an aquaponic system is typically at least twice the size of a hydroponic one.
Over time, though, aquaponics may end up being the less expensive route. Many of the costs are one-time charges, and once the system is up and running optimally, it takes care of itself to a large degree.
To see more options for varying aquaponic setups, check out this helpful video from Rob Bob’s Aquaponics and Backyard Farm:
A hydroponic set-up can be much more compact, leading to a lower initial cost. While you can certainly scale your hydroponic garden as large as you want, you can have a fully operational system using just one 5-gallon bucket or large plastic tote.
Emily says, “If you’re looking to grow a small herb garden and want a low-tech system, it can cost between $50 to $200, and for a medium one, between $300 to $1,000. For a high-tech system, it can cost more than $10,000.”
However, hydroponics does have the added cost of purchasing fertilizers, and that’s an ongoing cost. Depending on the current market supply/demand, fertilizers can be a pretty considerable expense.
2. Production Timeframe
Because aquaponic systems are essentially actual ecosystems, it takes time to achieve a balance that’s healthy for fish and plants. It can take anywhere from 3-6 months to build a thriving microbe population to convert fish waste into usable nutrients for your plants, and up to 18 months for optimal produce production.
With hydroponics, the initial stabilization process is much shorter. It typically only takes a couple of days at most to get your nutrient and pH levels adjusted to support plants, and about 1 month for optimal plant production.
3. Plant Choices
Since aquaponics relies on naturally-produced plant food, you don’t have the high and perfectly-calibrated nutrient levels that hydroponics offers. Because of this, aquaponics typically can’t support heavy-feeding plants (like tomatoes or peppers), and it’s best for non-fruiting plants like leafy greens, lettuce and herbs.
On the other hand, hydroponics offers a wider range of plant options since you can tailor the nutrient concentration minutely to support the needs of almost any plant.
4. Organic Certification and Sustainability
Hydroponics is not an “organic” growing method since it relies on chemical nutrients. But even though it’s not technically “organic,” there are other health and safety certifications that hydroponic growers can earn. And hydroponics will almost always be lower in pesticides and herbicides than crops grown conventionally in the soil.
Aquaponics is a more holistic approach: It takes advantage of a natural symbiotic relationship to reduce the need for chemical fertilizers and pH modulators. Thanks to this, aquaponics is a naturally organic method, and it also meets the criteria for truly sustainable growing.
When it comes to energy consumption, power outages and downtime can adversely impact an aquaponic system much faster than a hydroponic one. The filters in an aquaponic system run on a much shorter interval, so loss of electricity can lead to dangerous waste build-up faster.
5. Routine Upkeep
No matter which growing system you choose, you’re looking at some routine monitoring, maintenance, cleaning and upkeep.
Hydroponics is a more precisely-calibrated method than aquaponics, and you’ll need to check your system’s electrical conductivity (EC), pH, temperature, nutrient levels and other factors every 1-3 days.
A sterile growing system is your goal in hydroponics, and it’s definitely the more labor-intensive of the two systems. You’ll need to perform complete water changes typically every 2-4 weeks, and you’ll also need to clean your reservoir with diluted bleach or hydrogen peroxide on a regular basis.
NOTE: That discarded water from hydroponics is extremely high in nutrients, which could disrupt balances in natural ecosystems. That’s worth keeping in mind, especially if you live in an area that already has problems with phosphorous/nitrogen overload.
With aquaponics, you only need to check ammonia and pH about every 7 days or so. Plus, you almost never have to do a full water change in aquaponics- just periodic top-ups for water loss due to evaporation or plant transpiration.
Even when you do need to discard aquaponic water, it will have minimal to no effect on natural ecosystems since there are no artificially high nutrient levels.
6. Maintenance and Troubleshooting
Aquaponics can be more difficult to manage if something goes wrong. Since you’re raising fish in addition to your plants, there are more variables to take into consideration and more system parts to inspect when investigating an issue.
You’ll also need to monitor fish population. If your tank becomes overcrowded, the fish produce excessive waste that could clog/damage the system. But that’s actually a good problem to have- time to harvest some fish for dinner!
Problems in a hydroponic system are typically easier to diagnose and treat. Most of the time, adjusting the pH, adding some hydrogen peroxide to the tank or trying a different nutrient balance will correct the problem.
Hydroponics produces a most more consistent yield, and it’s much easier to estimate costs once the system is calibrated and functional. In other words, once you fine-tune your growing process, you can reliably replicate it as many times as you want in the future.
However, root rot, or fungus that attacks/destroys plant root tissue, is a common problem in hydroponics. Keeping your hydroponic tank properly cleaned and monitoring your plant health closely can greatly reduce the chance of root rot, and routinely treating your tank with hydrogen peroxide is another effective step.
Since there are more active components to aquaponics and the system is based on a natural function/cycle, harvests and growing timeframes can vary more. For example, if even one fish becomes ill, it can throw off the entire ecosystem for a time.
However, many aquaponic growers find that after they’ve established a healthy ecosystem, their yields are comparable or even occasionally better than some hydroponics systems. And you can’t overstate the benefit of being able to harvest both fish and produce from your aquaponic tank!
Interestingly, root rot almost never happens in aquaponics. In all likelihood, the friendly microbes that fuel the aquaponics system don’t allow the harmful fungi to get a foothold.
Similarities Between Aquaponics and Hydroponics
Both hydroponic and aquaponic growing systems have several common benefits to offer:
No Need for a Large Outdoor Space
Hydroponic and aquaponic gardens can live inside, so they are great for growers who have small yards or no yard at all. With fresh, affordable food being a scarcity in some areas, hydroponic/aquaponic growing could help provide needy communities with healthy food.
Fewer Pests and Plant Diseases
Since hydroponic and aquaponic gardens are usually fully indoors or in a sheltered outdoor location, the plants are far less likely to be attacked by insects or disease. Most of these plant enemies are introduced on the wind or from neighboring infected plants, and some insect larvae/disease spores can live in the soil for a few years.
Because hydroponic/aquaponic plants are protected from invaders and sickness, you’ll to apply pesticides or herbicides far less or not at all.
Less Prone to Seasonal Limitations
Since hydroponic and aquaponic gardens can be set up easily in greenhouses and indoor spaces, they are less affected by the winters’ frosts and shorter daylight hours.
This allows growers the flexibility to grow year-round, and to expand their options for which crops can flourish in colder seasons. Also, it makes fresh food production available to people who live in climates where the outdoor growing season is prohibitively short.
I’ve experienced this firsthand- the hydroponic crop I’ve grown indoors have thrived and given me fresh produce in the middle of our harsh Midwest winters.
In both types of systems, water is recycled within its tank, so the growing process is much less water-intensive than conventional farming. According to United States National Park Service, it’s estimated that hydroponics uses just 1/10th of the water than soil-based growing requires.
Who Aquaponics is Best For
An aquaponic set-up might be a great choice for you if:
- You’re interested in harvesting both fish and plants from a single system
- You’re willing to invest more time and money into a system for long-term use
- You’re comfortable troubleshooting a more complex system as well as caring for live fish
- You want a growing system that’s based on natural fertilization, plant-fish life cycles and is certifiably organic
- You’re comfortable with getting a variable harvest and growing mainly non-fruiting plants
In my opinion, aquaponics is the better system for long-term use if you have the space, time and money to build a large system. I really like the idea of growing a healthy dual harvest of both fish and plants using natural biological processes instead of artificial fertilizers.
Who Hydroponics is Best For
A hydroponic growing system could be the better choice if:
- You want to start harvesting plant crops sooner and with a lower initial financial investment
- You want more control over the system and a reliable crop output
- You need the option of a small system to fit in a limited space
- You want to grow fruiting crops
- You want the option to scale up your growing system in the future
- You’re comfortable with growing that’s not traditionally “organic”
As I mentioned earlier, I’ve used table-top hydroponics systems before, and they’re an awesome way to quickly grow fresh food any time of the year.
One thing that’s a clear benefit of hydroponics is the sheer number of ways you can build a system of almost any size. If you’d like to see some examples, I’ve written about many options for hydroponic systems that you can build yourself. Plus, a smaller hydroponic system can be a great way to experiment and gain experience if you have your ultimate sights set on a large aquaponic system.
Frequently Asked Questions about Aquaponics vs Hydroponics
Both aquaponics and hydroponics are awesome ways to get more fresh food into your diet. Based on my experience, aquaponics has the added benefit of a healthy protein source (fish), but hydroponics offers a wider range of plant choices and typically produces larger harvests.
Either system is a great choice- it really just comes down to the growing conditions you have available and how much time and money you’re able to invest.
What are your thoughts on aquaponics and hydroponics? Have you tried either method, and what was your experience like? Do you have any other questions? There’s no better way to learn than as a gardening community, so please let us know in the comments!