To live, people need food to eat and water to drink. That’s a simple fact. But with growing water scarcity around the world and an ever increasing population, we have to find better ways to produce the food we all need to survive. The solution could lie in one of several promising farming techniques like hydroponics, vertical farming, or aquaponics. That last one has technically been around since ancient times, but has been gaining a lot of interest recently. How is this old technique getting revived? Can nextgen tech really bolster age old symbioses, and build a mini ecosystem that creates more food with less water? Could aquaponics be the future of farming?

In past videos I’ve talked about vertical farming, as well as agrivoltaics, and how they’re changing how we should look at farming in general. Using technology in combination with different farming techniques can unlock a lot of potential, but why should any of us be interested in that?

Well, by 2050 the United Nations predicts there will be 9.8 billion of us on this pale blue dot.1 All those people need healthy food and clean water, but our current farming and agricultural techniques just aren’t up to the challenge.2 In fact in some cases they’re making it worse. Agriculture has been the single biggest driver for wilderness destruction. As a species we’ve cleared over a third of the world’s forests and two thirds of its grasslands just for farming.3 As we’ve destroyed these carbon-sequestering biomes we’ve released more greenhouse gasses into the atmosphere and seen a sharp decline in our planet’s biodiversity.34

On top of that arable land is shrinking. Every year, an area about half the size of Britain turns to desert, and by 2050 the forces of climate change and pollution will have cost us 50% of all currently arable land. And while that’s happening we’re going to need to increase food production by 70% to meet the world’s appetite in 2050.5 Not a great combo.

Then there’s the common practice of growing only one crop species in a field at a time, which is known as monoculture. This makes it easier on farmers, but monocultures deplete the soil of nutrients and moisture, causing irreversible soil erosion, and necessitating more water and fertilizer. Meanwhile monoculture’s lack of diversity has been shown to harm pollinators like bees, which isn’t helped by the increased reliance on pesticides.6

To make matters worse, agriculture uses an astonishing 70% of our drinking water in most areas.7 This is simply untenable when you consider the now regular droughts across the world. For example, the United States Southwest is in the middle of the worst megadrought in 1,200 years.8 Last year Europe’s drought revealed long hidden “hunger stones.” These hydrological markers were left by humans hundreds of years ago, warning that if the river was low enough for you to read them, then famine was sure to follow.9

That’s all grim stuff, but aquaponics might just be able to help.

Aquaponics is a portmanteau of “aquaculture” (AKA farming fish) and “hydroponics” (AKA growing plants in water), and it combines some of the best features of both to create an innovative, sustainable food production technique in a modest footprint. But how do you actually mix veggie and fish farming together?

There’s several subtypes of aquaponics, like the low-maintenance deep water variety, space efficient vertical farming, and the root-protecting nutrient-based beds. Generally speaking they all start with growing plants in a bed and raising fish in a tank.10 As the fish thrive and grow, they make a lot of … how should I put it … organic waste. Fish poop and food scraps. You don’t have to be an ichthyologist to know that swimming around in their own waste isn’t good for fish. As the waste breaks down it forms ammonia, which is toxic for most living things.11 But by using a bacteria called nitrosomonas, that ammonia can be turned into nitrite. The downside is that nitrite is actually even more toxic for fish than ammonia because it binds to the hemoglobin in their blood, preventing it from carrying oxygen. However, this is where our next bacteria comes into the picture, nitrobacter, which converts nitrites to nitrates.12 Now we have water swimming with fish fertilizer and nitrates that we need to get rid of, and hungry plants who love these compounds. We just pump the fishy water to our plants and they serve as a biofilter – eating up all those compounds and purifying the water, so it’s ready for the fish and the whole process to start again.13

The beauty of aquaponics is that it simulates a natural ecosystem, with plants, animals and microorganisms all working in symbiosis to make a self-contained, sustainable and self-managing system (somewhat). Just like a natural ecosystem you rarely need to add more water. The natural cycles at play here mean water in an aquaponics system can be continually reused, which reduces water consumption by 90% when compared to traditional agriculture.14 Since the fish are continually filling the water with plant food, you don’t need to add additional nutrients to the water as you would with hydroponics. However, you do get some of the big benefits of hydroponics, like plants growing larger and faster than traditional soil-based agriculture because of all the room to grow, fresh air, and constant access to nutrient-rich water.1415 And between the fish and lack of soil, there’s no need to use environmentally harmful fertilizers or worry about soil-borne pests.16

Another benefit of soil-less solutions like hydroponics and aquaponics is we don’t need to worry about arable land. As long as there’s room for an aquaponics facility, regions that aren’t otherwise suited to agriculture can start growing big, nutritious fish and vegetables. This can cut down on transportation costs and carbon emissions too, as spaces like empty warehouses or rooftops in the heart of population centers can be converted into productive aquaponic farms.17 And fish are one of the most efficient animal protein sources. The feed conversion ratio (FCR) describes how much feed is required to produce 1 kg of meat. The most commonly eaten animal protein on earth right now is pork, which has an FCR of 4:1,18 but fish like salmon or tilapia clock in at around 2:1 or less.19

But is this technique scalable? Well, it might be the most scalable piece of tech we’ve ever explored on the channel. You could create a small system to raise herbs and decorative fish on your kitchen windowsill, but it can scale up to backyard aquaponics systems or all the way up industrial scale … kind of like Superior Fresh’s 6-acre industrial agribusiness greenhouse.20 Combining your protein and vegetable needs into the same footprint (no matter the size) is of course an efficient use of water and space. Just like we touched on earlier, aquaponics can incorporate vertical farming techniques to increase that space efficiency even further.21 With more food from a smaller footprint, and less carbon emissions and water-use, what’s the catch of the day?

While aquaponics boasts many of the benefits of a functioning ecosystem, it also suffers from its weaknesses too. Just like a natural ecosystem, one problem can cascade into catastrophe. Even though there may be fewer pests due to a lack of soil, you’re still raising multiple types of organisms that have different disease vectors. And because the fish and crops rely on each other to survive, if a lucky illness manages to take out one half of your aquaponics set up, the other side is doomed as well.22 And if bugs do get a foothold in your system you can’t use chemical pesticides to get them out or you’ll risk poisoning your fish too.22

Have you ever had to take care of a fish? As anyone who has kept them can tell you, keeping the parameters just right can be a challenge. Most fish species prefer pH levels around 7-8, while plants tend to want more acidic water with a pH of 5-6.5. Of course the bacteria prefer alkaline waters with a pH of 8-9.23 Making sure every organism gets what they want leaves the caretaker with a slim Goldilocks zone and little margin for error. Complicating things is the fact pH levels oscillate all the time due to an array of natural factors. So while lower maintenance than say, traditional farming or hydroponics, aquaponics requires near constant monitoring. Population control presents another issue. Too many fish and their waste can clog your system or overwhelm your plants and microorganisms. If fish feel too crowded or stressed they’ll stop growing or just drop dead, which isn’t ideal for a food source.24 But too few fish and now your bacteria and plants start to starve.25 Then there’s algae, who love an aquaponic ecosystem for all the same reasons that your crops do. If conditions in your aquaponics tank are just right, it can cause a suffocating algal bloom.26

There’s also temperature concerns. Once again fish, plants and microbes tend to have slightly different preferences here, which leaves you with little margin for error11 And if your aquaponics system isn’t inside of a temperature controlled structure, maintaining the correct temperature poses an even greater challenge. Tilapia is considered the gold standard for aquaponics because it can grow to a mature size in just 8 months, it self regulates its population, and is very resilient to a wide range of temperatures and water qualities. But even tilapia start to struggle in temperatures below 65°F(~18°C), and will die if the water temperature dips below 50°F(10°C).27 That means the gold standard of aquaponics can’t be farmed outdoors all year except in very warm places.28 There are of course fish better suited to cold temperatures like the trout used in Superior Fresh’s massive facility,20 but they’re not as easy, quick, or cheap to raise as tilapia. Outdoor facilities face yet more challenges in the form of increased water loss from evaporation, are more vulnerable to outside pests and predators impacting your stock, and are subject to local weather.29 30 This doesn’t invalidate outdoor aquaponic systems but it certainly makes them more challenging for the types of communities that might need them most.

Aquaponics also may not be as sustainable as they first appear. While we shouldn’t discount the water-saving benefits, keeping all that water moving requires precious electricity, as does keeping the grow lights on. This can drive up fish and produce costs compared to traditional farming.31 32

So how does the economic side of the equation look? The initial investment for an aquaponics system can be steep. Aquaponics expert Murray Hallam puts the startup cost of even small aquaponic farms at about $20,000 – $50,000. Something that size would only be capable of earning between $500 to $1,000 a week, but location and market factors can cause your ROI to vary widely.33 A John Hopkins university study of over 250 aquaponics facilities showed that only a third of them were profitable.34 Granted, many of the aquaponics facilities studied were newer and expected to be profitable the following year, but still, these aren’t the kinds of numbers that excite entrepreneurs or investors. The study also found that the most profitable aquaponics farms didn’t just rely on aquaponics, but diversified their “revenue stream by selling non-food products, services, or educational trainings[sic].”34 Ultimately, the study concluded more research was needed. A separate 2019-2021 study reached a similar conclusion, noting that the most profitable aquaponics ventures were more likely to have warmer weather, access to high end markets and were selling things beyond the food they produced.31 And a literature review from Oklahoma State noted that data from the plant side of aquaponics was promising, but the fish side tended to break even or incur a net loss.35 Cornell’s Michael Timmons, a specialist in Biological and Environmental Engineering also noted, “The aquaponics industry itself is really, really, really, really small… They’re very, very difficult … (and) they almost always fail.”36

In all these studies, it was clear that it didn’t matter whether you’re talking about soil-based, aquaponic, or any other farming method, the profit margins on farming in general are slim. And while the crops grew faster with aquaponics and could be sold at higher organic-level prices, it’s hard to keep up economically with traditional farming’s cost advantages.15 Dirt and fertilizer are cheap, and sunshine is free.37 So while it’s hard to state conclusively at the moment, it does seem like traditional, wasteful agriculture has the edge in profitability, at least for now.36.

Aquaponics has exciting, tangible potential, but the technology isn’t mature enough for us to tell if it’s really a commercially viable farming-alternative, or just another cool gadget for the eco-friendly, resilience-minded hobbyist. The challenges are many, but if we can fully realize this technology and bring the costs down? The benefits of healthy fish and veggies farmed sustainably just about anywhere are too good to pass up. There’s reasons to be optimistic too. In 2020 Superior Fresh produced 200,000 pounds of salmon and 3 million pounds of salad greens in chilly, landlocked Wisconsin. In traditional agriculture this would have taken over 100 acres of land, but thanks to aquaponics, Superior Fresh did it in only 6 – and it was profitable enough that they’re expanding their aquaponics operations.20 If their techniques prove to be repeatable, then I’ll be very hopeful about aquaponics as a commercial avenue. And even if we can’t bring the costs down, maybe the price is right for local, sustainably grown, high-quality food in places that just wouldn’t have access to it otherwise. Aquaponics may not be the silver bullet for the future of all farming and food production, but it could be a compelling solution for specific regions of the world … or your backyard.

  1. World population projected to reach 9.8 billion in 2050 ↩︎
  2. UN’s Food and Agriculture Organization, FAO statistics ↩︎
  3. After millennia of agricultural expansion, the world has passed ‘peak agricultural land’ ↩︎
  4. UC Davis, ‘Grasslands may be more reliable carbon sinks than forests in California’ ↩︎
  5. Feeding ten billion: how can we farm our unfarmable land?, NatGeo ↩︎
  6. EOS Data Analytics, ‘Monoculture Farming In Agriculture Industry’ ↩︎
  7. World Bank, ‘Water in Agriculture’ ↩︎
  8. Journal of Nature, ‘Rapid intensification of the emerging southwestern North American megadrought in 2020–2021 ↩︎
  9. Czech Hydrometeorological Institute, ‘Low Water Stage Marks on Hunger Stones: Verification for the Elbe River from 1616 to 2015’ ↩︎
  10. Go Green Aquaponics, The Different Types of Aquaponics Systems ↩︎
  11. University of New Mexico, ‘Important Water Quality Parameters in Aquaponics Systems’ ↩︎
  12. Go Green Aquaponics, Bacteria’s Role In Aquaponics ↩︎
  13. Nelson Pade, How Aquaponic Work ↩︎
  14. Aquaponic Systems: Nutrient recycling from fish wastewater by vegetable production, Graber & Junge ↩︎
  15. Structural and biophysical properties of whole leaf and root tissue and isolated cell walls of common green bean and tomato seedlings grown in an aquaponics system relative to soil-grown counterparts, Knoll & Mary ↩︎
  16. Go Green Aquaponics, Aquaponics and Hydroponics: What’s the Difference? ↩︎
  17. Research shows aquaponics can be profitable under the right conditions ↩︎
  18. Challenges of Sustainable and Commercial Aquaponics, Gocdek et al ↩︎
  19. The Ultimate Guide to FCR ↩︎
  20. Aquaponics Presents A New Way To Grow Sustainable Fish And Veggies ↩︎
  21. Upward Farms announces plans for world’s largest indoor vertical farm ↩︎
  22. Go Green Aquaponics, The Most Common Aquaponics Problems ↩︎
  23. Water Quality in Aquaponics Systems ↩︎
  24. University of British Columbia,’Tilapias are not precocious, they are just resilient’ ↩︎
  25. Challenges Of Aquaponics Development For Sustainable And Commercial Use ↩︎
  26. Algae in Aquaponics ↩︎
  27. Farming tilapia: life history and biology ↩︎
  28. Go Green Aquaponics, Raising Tilapia ↩︎
  29. Go Green Aquaponics, The Best Cold-Water Fish for Aquaponics Systems in Colder Climates ↩︎
  30. Go Green Aquaponics, Guide to Aquaponics Greenhouses ↩︎
  31. ‘System design and production practices of aquaponic stakeholders,’ Patillo et al ↩︎
  32. ‘Economically viable aquaponics? Identifying the gap between potential and current uncertainties,’ Greenfield et al ↩︎
  33. The Cost of Commercial Aquaponics ↩︎
  34. ‘Commercial aquaponics production and profitability: Findings from an international survey,’ Crowe et al ↩︎
  35. Economic of Aquaponics ↩︎
  36. Next wave of ecopreneurs hopes to find key to making aquaponics profitable ↩︎
  37. Aquaponic farming saves water, but can it feed the country? ↩︎

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