Is it possible to set up a saltwater aquaponics system to grow vegetables? I’ve never seen or heard of such an installation but the topic is occasionally raised among those new to aquaponics. An honest query really considering saltwater shrimp, shellfish and/or fish such as red drum are valuable and sought-after livestock.
Taking this a step further, saltwater aquaponic installations would look a lot cooler when you have damsels, tangs, butterfly, rays and sharks swimming around vs freshwater species which look rather dull in comparison.
Aquaponics can only use freshwater, right?
I’m guessing most aquaponic farmers believe as I, salt water would kill most vegetables. Given this accepted tenet, we’d therefore use only fresh water and freshwater fish such as tilapia, bluegill, trout, perch or catfish. However, let’s consider the potential of using saltwater given more than 70 percent of the world is covered in it! This would definitely boost overall food production on the coasts where most of the population lives.
Vegetables tolerant of saltwater
To my surprise, there are plenty of vegetables tolerant of salt water. Following is a post about salt-resistant crops: http://blogs.ifas.ufl.edu/pinellasco/2014/03/28/salt-tolerant-vegetable-gardening/ Here is another article exploring the same:
This article is about a Dutch farmer looking to grow potatoes using saltwater: http://www.micronesiaforum.org/index.php?p=/discussion/13710/fruits-and-vegetables-grown-in-saltwater-could-help-solve-world-food-shortage
Saltwater aquaponics for purely saltwater crops
So let’s take this even a step further. Rather than building and experimenting with growing traditional vegetable crops in saltwater, why not grow saltwater aquatic plants with commercial value in these systems. Seaweed is a great example and here’s an article about growing this crop using aquaponic methods: http://aquaponicsjournal.com/docs/articles/Seaweed-is-Common-Denominator.pdf
More on saltwater aquaponics at this wikipedia page: https://en.wikipedia.org/wiki/Saltwater_aquaponics
Eggplant and peppers showed extremely anemic growth.
Growing vegetables on a patio in dirt-filled pots seems like an easy endeavor, but theory does not always translate to practice. Why use aquaponics as an alternative? Let us explain.
Aquaponics vs Pots for Growing Vegetables
Following are challenges with growing in dirt pots: 1. you needed to carry dirt which is heavy — especially tough when you’re on the fourth floor; 2. the soil is devoid of nutrient content or it was mystery to the amount of nutrient content it contained; and 3. you don’t necessarily get enough sunlight for the plants to grow healthy since patios are usually covered. Sunlight, if you are lucky, comes in at angles, either in the morning or late afternoon. We discovered why so many patio gardeners try and fail — and probably never try it again.
Aquaponics using LED Lighting is the Solution
However, we didn’t give up and turned to what worked for us before, aquaponics using artificial lighting. Yes, water is heavy too but it can be poured with a hose and drained! And in regards to the nutrients, aquaponics is a mutually beneficial system where fish waste supplies nutrients (nitrogen) for plants, which in turn would remove these elements that would be toxic to the fish. More on the benefits of aquaponics here.
LED lighting is the ideal solution for dimly lit patios (or deck surrounded by lots of trees). Although expensive to purchase, they are low power consumers, could potential provide the right, if not perfect wavelength of light and be turned on and off using a timer so you have complete control of the growth using this lighting.
Growing Vegetables Using Two Organic Practices
During the last six years in Virginia, we grew our vegetables in 8 raised beds, filled with rich compost sourced from foliage, yard waste and surplus vegetables; and in two custom-built aquaponic systems. Read about benefits of using aquaponics here.
Our primary aquaponic system was a large installation outside which grew mostly stem plants such as peppers, tomatoes and basil using bluegill as the livestock living in a 600 gallon pond. We also had an indoor system which we grew mostly leafy vegetables such as bok choy, lettuce and arugula using tilapia as livestock in a 70 gallon tank.
Vegetables grown in post yielded no real success. We used bagged dirt in pots.
Have A Fish Tank? You Have a Potential Aquaponics System
For our small patio, we needed to scale an aquaponics system even smaller. We decided to build an aquaponic system around an old 55-gallon tank we used as a saltwater aquarium. Like our larger systems in Virginia, we will build a flood and drain system, just on a smaller scale.
As we do our build, we’ll provide updates on progress on this page.
- Small-Scale Aquaponics Patio System Build