Did you know that growing flowers in aquaponics uses 90% less water than conventional farming? The practice, which involves growing fish and plants together, shares some similarities with its more popular cousin, hydroponics; they are both sustainable and highly effective options for growing plants without the use of soil.  But unlike hydroponics, which relies on chemical nutrients being added, aquaponics takes advantage of fish waste to nourish the plants.

Not only does growing in aquaponics use far less water, but it’s also inherently organic, produces no waste, and doesn’t require any soil.  And thanks to the nutrient-dense fish waste, aquaponic farmers report that their plants grow faster, healthier, and are ultimately more productive than their conventionally-grown crops. 

But despite an increasing number of vegetable farmers turning to aquaponics as a sustainable solution, only a couple of flower farmers across the nation have embraced it. There are a few practical reasons for this (the start-up costs are a big challenge - more on this in a minute) but much of the problem lies in a lack of public awareness surrounding its potential within commercial floriculture.  With greater understanding and more research, aquaponics is poised to become an integral part of the future of flower farming.

History

The term “aquaponics” wasn’t coined until the 1970s, but the concept of growing fish and crops in tandem has a rich history. The practice can be traced back to several cultures and regions, including Southeast Asia’s early use of paddy fields thousands of years ago.  The Aztecs’ use of Chinampas, too, was another historical marvel that was believed to have begun around 1000-1150 A.D. Their innovation was borne from the need to grow food in wetlands (the capital, Tenochtitlan, was surrounded by swamps).  In an effort to farm on land that was otherwise unusable, the Aztecs created man made floating islands over these shallow waters. These innovative growing areas, supported by underwater fences, were situated over fish-filled shallow waters.  The fish byproducts provided nutrient-rich soil and their crops were successful.  Chinampas are still occasionally used by farmers in and around Mexico City. 

As a modern agricultural technology, however, aquaponics has only been utilized for about fifty years.  In the 1970s, researchers at the New Alchemy Institute in Falmouth, Massachusetts began researching aquaculture and the symbiotic relationship between fish and plants.  Inspired by their work,  North Carolina State University’s Dr. Mark McMurtry developed what is believed to be the first closed-loop aquaponics system in the mid-1980s.  (“Closed-loop”, here, refers to the system being entirely self-sustaining and not needing any outside nutrients or chemicals to maintain the ecosystem.  The water is recirculated within the system, from fish to plants and then back to fish.) 

Aquaponics Today

As farmers seek more sustainable solutions in a period marked by climate change, water scarcity, and soil degradation, there appears to be a slow but steady rise in the overall use of aquaponics and hydroponics for crop production. I use the term “appears” here because, while discussion surrounding these growing methods has increased (even a simple Google search on the subject yields far more results than it did just a couple of years ago), there is a notable lack of peer-reviewed research or general data on the subject. This is especially true as it relates to aquaponics within the cut flower industry.  

Much of what is known about aquaponics for flower production is anecdotal or provided by home gardeners and hobbyists; there are only a couple of known farmers in the United States that are growing cut flowers in aquaponics on a commercial scale.  One of the first is Grateful Gardeners, a team in Poolesville, Maryland, founded and led by husband-and-wife team Dr. Tom Precht and Sarah Daken.  Tom and Sarah have successfully grown and harvested numerous gorgeous flowers from their system (which includes two 500-gallon tanks of koi fish), including dahlias and tulips! 

How it Works

Simply put, aquaponics takes advantage of a natural ecosystem created between fish, plants, and beneficial bacteria.  When fish excrete waste (yes, their literal poop and pee!), toxic ammonia is released into the water.  Beneficial bacteria break this ammonia down first into nitrites and then, ultimately, nitrates.  This nitrate-filled “dirty” water supplies the plants with a nutrient-rich fertilizer, and the plants, in turn, naturally clean the water by absorbing the nitrates from it. The water recirculates back into the fish reservoir.  

The actual mechanics vary depending on the type of system being used, which include “raft” (sometimes called “deep water culture”), media-filled beds, and nutrient film technique (NFT). The raft system is the most commonly used in larger commercial systems, as it is efficient with space and best suited for scaling. Media-filled beds, by contrast, are a flood-and-drain method that tends to be better for smaller growers.  As the name implies, this system uses trays filled with a growing medium (clay pebbles are a common choice) and is also arguably the most suitable for a DIY project.  Lastly, NFT systems are similar in function and design as most hydroponics systems. These systems flow water through channels (usually PVC pipes) and are best for plants with shallow roots; as a result, they’re not recommended for most flower growers. 

In theory, once a system is properly installed, it’s self-sustaining and the only regular task is feeding the fish.  But of course, the actual practice isn’t always so simple!  Because it’s a delicate ecosystem, it requires frequent monitoring and maintenance.  If something gets out of whack - like the pH, temperature, or ammonia levels - adjustments have to be made, and in some cases, they have to be made very swiftly to ensure the health of both the fish and the plants.  The trade-off, though, is that in many ways it’s lower maintenance that conventional farming.  No need to worry about soil health, fertilizer, or watering! 

Renewable Energy Sources 

The vast majority of aquaponics systems require electricity in order to maintain the pumps and filters.  While most systems use a surprisingly small amount of power relative to their size and production, they can be made even “greener” by taking advantage of renewable energy sources.  There are some reports of solar-powered and wind-turbines being used to power entire systems. 

While the initial costs of these renewable energy sources tends to be expensive, this could make aquaponics viable for “off-grid” living or nontraditional locations.  

Challenges

For the average flower farm, the greatest drawback is the initial start-up cost.  Commercial systems run in the tens - or even hundreds - of thousands of dollars..  While the system can eventually pay for itself due to the lower water costs, higher yields, and fewer inputs (no need to pay for fertilizer!), it comes with a price tag that is simply out of reach for the average farmer.  Sometimes these costs can be defrayed by grants or other funding, but that’s not always feasible.  As a result, some savvy farmers have turned to building their own systems but that, too, isn’t a practical solution for most folks.  

Additionally, understanding and maintaining an aquaponics system requires skill and technical knowledge. As mentioned earlier, the systems require a careful eye and the ability to troubleshoot if something gets out of balance, and a successful aquaponics farmer likely needs both some specialized education and training.  Getting a system up-and-running successfully can also take weeks or months, which can be a detriment to many growers. But with money, knowledge, and a little patience, the payoff can be tremendous.

Aquaponics for Cut Flower Production 

Traditionally, aquaponics has been used for vegetables and, more specifically, leafy greens like lettuce.  This growing method has been far less commonly used for cut flower production although it appears as though most specialty cut flowers can be grown in aquaponics.  Roses, sunflowers, zinnias, marigolds, and lilies are just a few varieties that have anecdotally been reported as successful.  The team at Grateful Gardeners recently demonstrated that even dahlias can mature and flower successfully in an aquaponic system - and with about 95% less water, too! (See research article linked below for more information). 

A couple of things have to be carefully considered when growing in aquaponics.  Like growing flowers in the field, a plant has to have the proper photoperiod (amount of daylight), and temperature.  Additional factors include ensuring the proper pH level, water temperature, and ammonia levels, although it’s not yet fully understood how exactly how impactful each of these factors is to the development of flower growth; while there’s enough anecdotal evidence to suggest that most flowers can be grown in aquaponics, significantly more research needs to be conducted in order to ensure that they are viable in commercial floriculture.

Beyond Cut Flowers

A successful aquaponics system yields not only valuable plants, but also fish.  Tilapia are among the most commonly chosen edible fish for aquaponics systems.  Hardy and tolerant of extreme-water conditions, tilapia are easy to maintain and also a healthy and protein-rich food source.  Other popular edible fish choices include catfish and carp.  Ornamental fish such as koi or goldfish are also widely used. 

While this specific article seeks to address the benefits of aquaponics within the cut flower industry, any discussion about the subject is not complete without underscoring the critical potential that it has on the possibility of being part of a solution to the global food crisis.  Unlike other food production methods, aquaponics can be implemented in regions of the world that are suffering from extreme water shortages, limited land area (often due to overcrowding), or poor land or soil quality.  In sum, aquaponics as a modern agricultural technology allows fish, vegetables, and flowers to be raised and harvested in places where they could otherwise never have been grown.  

In Sum

It’s no secret that the cut flower industry is in need of change.  Aquaponics is one organic solution that can yield flower farmers with beautiful, organic blooms while using a fraction of the water, no soil or additional fertilizer, and zero waste.  With a greater public understanding and more research, it is my sincere hope that aquaponic systems will become a more practical option for flower farmers across the nation. As good environmental stewards, it is our duty to seek out and adopt sustainable practices -  for our flowers, for the earth, for each other, and for the future.