I’ve always liked keeping aquarium fish, even as a kid. I strongly preferred using live plants instead of plastic ones, and arranging the tank elements so that it looks more natural.
Fishing was an activity we usually did while camping, and eating fish we caught as well.
I also like growing vegetables, and eating them too!
So when I found aquaponics (AP) many years ago, it was really a good fit for me. Turns out, it’s a very good match for the fish and plants as well.
I’ve built an aquaponics system before, and plan on putting a larger one into my greenhouse.
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What is aquaponics?
Aquaponics is a growing technique that combines aquaculture (growing fish) and hydroponics (growing plants in water).
Many traditional peoples have farmed fish in one form or another for a very long time.
The Chinese have been using a sustainable aquaculture system consisting of carp, mulberries, and silkworms for thousands of years.
But hydroponics is a relatively recent technique, where a chemical soup for plants growth that must be discarded when nutrients are used up.
This seems like a waste to me, and it’s not good for our natural waterways. And traditional gardening and aquaculture can use a lot of water.
But aquaponics is a recirculating system. The fish waste water is pumped to the plants, where special bacteria break it down from ammonia into nitrates then nitrites so plants can use it.
After the plants, the clean water returns to the fish, which mimics the natural ways waste water is cleaned.
Sometimes there is a solid waste removal step before the water goes to the plants. This depends on the fish stocking density, planting density, and how well the system can handle the waste.
Worms can be used to help clean the solids. They love that stuff!
The plants can be grown in deep-water culture (DWC) with floating rafts, wicking beds, or media grow beds.
Media beds are containers filled with gravel, expanded clay pellets, or perlite. It is used by plants to put their roots into and keep them upright.
Aquaponics systems shrink down the larger sizes of the natural systems into a package small enough to put in any backyard, or even indoors.
It’s very popular in Australia, and they have done some great innovations and work in AP.
What can you grow?
You can grow just about anything in aquaponics that you grow in the ground. Not everything grows the same way, though.
For plants without strong roots like lettuce you can grow them in DWC. Root crops do better in wicking beds. Everything else can do fine in media (gravel) beds.
But if you don’t want multiple bed types, you can just grow everything in media beds. Root crops may be a little more prone to rotting and have more fine hair roots, but you can adjust to water level in the bed to compensate.
You can even grow things like fruit trees in beds, you just need a deeper bed for the roots.
There’s also the option to use towers or horizontal pipes and trickling water down them. Towers are often used for plants like strawberries, and pipes for lettuce and other greens.
Some people do use AP to grow (ahem) “tomatoes”, and it works great for that too.
You should grow each plant in it’s season though. Cool season crops (lettuce, broccoli, peas, spinach) get planted when it’s cool, of course.
And summer crops (tomatoes, beans, squash, cucumbers) are planted when it’s hot.
As far as fish goes, there are lots of options. To start the system’s nitrogen cycling, many people use cheap feeder goldfish from the pet store.
Tilapia is probably the most popular AP fish, especially in warmer areas. Bluegill and sunfish, carp, trout, perch, and catfish are also commonly used.
Like plants, fish species have a certain temperature range they do best in. Trout want the water much colder (and with lots of dissolved oxygen) than catfish or tilapia.
So pick fish that will do well during the time of year and temperature you want to grow them.
What are the benefits?
Simply put, much greater production of fish and plants.
Fish are stocked in greater densities than is possible with aquaculture, because of the plants cleaning the water.
Plants grow much faster in a aquaponics system, because the are not stressed for water and always have access to good nutrients.
There are also much fewer weeds for competition and pests in an aquaponics system. The beds are usually off the ground, and so pests can’t find them as easily. You also get fewer weed seeds blowing in.
And since you’re not starting with a dirt seed bed that contains thousands of weed seeds, much fewer weeds sprout in the beds.
Because the fish are sensitive to pesticides/herbicides and chemicals, traditional methods are out for controlling pests. This has the side benefit of requiring the system to be natural, if not organic.
It also doesn’t require a lot of time or inputs to keep the system going. More on this later.
Fish waste doesn’t support E. coli like mammal manure does, which is used on traditional crops. So you’re much more likely to get sick from grocery store produce than from your AP system.
Lastly, because the system is recirculating, aquaponics uses much less water than other growing methods.
Are there drawbacks?
An aquaponics system can be expensive to build, especially if you buy all parts new.
But it doesn’t have to be. There is a huge community of DIY backyard aquaponics enthusiasts who build systems for very little out of pocket money.
Most people use an electric water pump to move the water from the fish tank to the grow beds. So there is a cost for power.
But from my research, most people put in too big of a pump, and run it too often. This leads to excessive electricity costs.
Some people do manage to run aquaponics off-grid, but it does require more investment with a solar system. It also might require some redesigning, since using a smaller pump (with less power draw) is desirable when off-grid.
The AP system will likely require some form of aeration, either air pumps and stones or air blowers, depending on your setup.
It does require monitoring the water quality, and adjusting fish feeding rate as well as checking filters and plumbing for problems. This doesn’t have to take a lot of time, though.
You also have to know what you’re doing to keep the fish alive. But if you can keep aquarium fish, you can do aquaponics.
Water quality is very important in the first few months. You only need to check it weekly or so as the system matures and stabilizes.
And speaking of fish food, you will have to supply food to your fish. Get a good, complete fish food, preferably organic. But you only need a few inputs for AP, along with iron, potassium, and calcium.
You also may want a greenhouse to get the best performance out of an AP system. But extended seasons would require some form of protection in the dirt garden too.
You’ll need a fish tank, some sort of growing bed container, a pump, and plumbing.
The details are up to what you want to grow, and your budget.
You should consider different design types, depending on your particular situation.
For example, CHIFT-PIST, means “constant height in fish tank, pump in sump tank”.
In this design, your fish tank remains at a constant level and overflow goes into the sump. The pump moves water out of the sump, which goes to the grow beds, and ends up back in the fish tank.
Likely you will also want a flood-and-drain setup, where the bed are filled with water then allowed to empty. This makes sure there’s enough air to the roots to prevent rotting and allow plant respiration.
Aquaponics is a great way to produce a lot of food in a little space, for very little money. Properly set up, they can produce food nearly or all year round.
Start building your system today!
backyardaquaponics.com Site and forum. Tons of great info!
aquaponiclynx.com Great blog with AP info. TCLynx has a ton of posts on backyard aquaponics forum, too.
University of the Virgin Islands AP system
Travis Hughey Free Barrelponics Manual
Murray Hallam – Australian AP systems, videos, courses
Aquaponic Gardening by Sylvia Bernstein
OK, that’s all folks! Do you have any questions or comments about aquaponics or anything permaculture? Ask your question down below and let’s talk! You can also use the contact form, or email me at info at thepermaculture dot life.
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