Starting With Aquaponics
This next contribution in our new Resilience Spotlight series, featuring stories from Peak Prosperity readers, comes from reader z. It details how asking the right questions will lead to the right answers, even for those with limited resources.
About seven years ago, I decided that I wanted to grow some vegetables and herbs in my backyard. Having very little time and money to spend on the garden, I looked for ways to cut down on costs and labor, and found aquaponics, which combines aquaculture and hydroponics.
The drawings and explanations I found online were a bit daunting, but I gave it a shot, and liked it so much I’ve kept going ever since.
For those who have never seen or heard of aquaponics before, here is my first system, which I built seven years ago and still use today – it cost a total of $40 and about 4 hours of labor:
First, I bought a used agricultural 1 m3 plastic container, cut it about 30 cm from the top, and flipped the cut upper part (AKA the growbed) so it rests on the bottom part (AKA the pool). Next, I filled the pool with water and fish, and the growbed with small lava rocks (pumice stone) and plants. The final stage was to install a small aquarium pump leading the water from the pool up to the growbed, and a siphon letting them back down using gravity.
Here is how it works:
- the water from the fish pool, containing nutritious fish poop, is continually pumped up;
- the rich community of bacteria, which lives on and in the porous pumice, transforms the poop into organic fertilizer;
- the plants use the fertilizer to grow; and
- the clean water circulates back to the fish.
I found that aquaponics fulfilled what I originally expected it to, which was to be very cheap in both money and labor. There is no need to ever fertilize or water the plants, and the only input to the system is fish feed and electricity for the pump.
However, there are several advantages which are more subtle. For example, if you look closely at the pictures you’ll see that the plants are quite crowded, much more so than is recommended for “regular” gardening. Aquaponics enables this because the plants have all the water and fertilizer they need, which also makes them grow faster than usual (sometimes up to twice as fast as identical plants that I plant in a soil patch nearby). The plant roots are white and clean, since there is no soil.
This is especially nice with tubers and onions (such as the ones in the picture) that require a lot of cleaning in regular gardens:
Another nice thing is that because the growbed is detached, there are hardly any weeds or diseases so I (almost) never need to use any herbicides or pesticides, or perform tedious weeding. Every few weeks I top off the water that evaporated from the fish pool, and check that the pump and siphon are working properly. Every few days I feed the fish – I grow mainly carp, which are sturdy and rarely get sick — who like to munch on algae and keep the pool clean, and are very tasty on the grill with some lemon and garlic.
I think that the main obstacle that prevents people from trying aquaponics is that once you start reading online, it’s very easy to become intimidated by technical jargon about chemical parameters such as pH, nitrites and nitrates, types of siphons, fish care and a thousand other things. These are of course helpful to the experienced gardener, but in no way are necessary for the beginner to worry about.
Speaking from experience, if your pump and siphon work, it’s very difficult to fail at aquaponics. I never measure the water parameters, weed, or tinker with the system in any way, and it still works nicely year after year. The siphon is probably the most complex part of the system, and some care should be taken when installing it, but in fact it is nothing more than three plastic tubes, one inside the other. Its purpose is to let the water amass in the growbed, and then – when they reach a certain level – drain it all into the fish pool. When the water drains, the plant roots get oxygenated, and when the water rise , the roots get hydrated and fertilized:
There are many online aquaponics tutorials out there, concerned with everything from system design, how to design your siphon, which fish and plants to use, how to measure pH, and much more. You can read them, but as always, the most important thing is not to over-plan, just go ahead and start with a system that is as cheap and as simple as possible.
Make it as small or as large as you like, use materials that are handy around you, and take pride in organic vegetables that you grow for yourself.
Love aquaponics. Top of my list for productive hobbies if I ever get the space for it. I didn't realize you can eat carp. Most people online use talapia, but I suspect you have to do a lot more tank cleaning with talapia since they don't go around eating literally anything.
do you have this thing indoors? Does the room get humid?
Macro – this particular system is outside, but I have another one that is in a closed shed and it does not get overly humid, the evaporation rate is quite slow. If you have no space for a dedicated system, try putting a flower pot on top of your indoor fish aquarium, to create a micro system that works very nicely.
I pretty much bombed in my attempt to do aquaponics.
I'm not saying don't try it, but you need to control for some variables and you need to know what they are.
For me the two hardest things to deal with were temperature and the nitrous cycle (is that the right term, Adam?). Anyway, I'd advise you to start the cycle before you introduce fish to the system. You can do that with "liquid seaweed" or, the cheaper way is just to introduce the right amount of Ammonia in the system (it is that cleaning product that is sold by the gallon), that way, the cycle is already working by the time you introduce the fish into the system (maybe 6-8 weeks after you start the cycle).
I wanted to raise native fish – delicious bluegills and perch. They start dying when water temperature gets into the high 70s [F] and in my 75-gallon tank in the summer – in a greenhouse – that temperature is reached all too easily. So most of the bluegills and perch died. Then I tried Talapia in my basement. Tilapia are South American fish. They cannot survive in water temperatures below about 50 degrees F. My basement gets well into the 40s in the winter, so the Tilapia also died. I did manage to grow plants with goldfish in the system in all kinds of temperatures and nitrogen levels. they are really hardy.
If you have the right habitat/climate for fish and plants year-round I would not want to discourage you from trying Aquaponics, just plan carefully.