Category Archives: Aquaponics

Aquaponic Tomato Plants

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I took a break from my aquaponics project as I was getting discouraged by seeing the previous batch of seedlings dying a slow death on top of my aquaponics plant tank. It seemed like I had missed some important point in the process of growing aquaponic plants, so I actually drained the whole plant tank, cleaned it, and installed a traditional filter in the fish tank / aquarium to keep the pet fish happy. That’s how fed up I was with my aquaponics problems.

… But I soon got too annoyed with the empty plant tank and my unreached goal of bringing this beast into production mode, so I went outside an started cutting side branches off my large tomato plants that I’m growing in self-watering containers beneath the south facing wall of the house. I learned from the ebook “How to Grow Juicy Tasty Tomatoes” that cuttings from a mature plant will easily grow into new plants if you stick the cuttings into the soil. Fortunately it works with aquaponic coconut fibers too:

The cuttings grew into tall plants, actually a bit taller than I have room for beneath the ceiling. The maximum grow height available in this system is small since the fish tank must be placed beneath the plant tank, and the fish tank in this case is an ordinary aquarium which you what to place on an aquarium table to be able to enjoy the fish without having to lay down on the floor ;-)

A quick look at the new tomato plants gives you the impression that they are healthy, and the stems and leaves have a healthy color:

But if you take a closer look at some of the largest tomato plants you’ll find that some of the leaves have wilted:

(WARNING: Oldest aquaponic joke coming up: “I’m sure I gave them enough water…” Ha. Ha.)

I have to find out what’s causing this, and even the small developing tomato flower stems are affected by this too. The leaves turn dry and crispy and turn into dust if you squeeze them.

I wouldn’t say that the submerged roots look particularly healthy:

Rasmus noticed the same brown stuff on the roots of my previous batch of aquaponic plants and recommended adding air bubbles directly to the plant tank. I think it helped back then but I forgot to reinstall the air pump after I cleaned up the plant tank.

Lots of challenges still with this relatively new aquaponics home system in the corner of my living room. And I’m still having wet dreams about adding automatic electronic measurement of pH and conductivity.

Aquaponics Tanks

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When I think of an aquaponics tank I normally think of a rectangular container, which is like the aquaponics plant tank I built for myself, but take a look at these plant ‘tanks’, which are made from PVC tubes instead:


Photo by Kanu Hawaii.
These plant tanks, or plant grow beds, take up very little space and evaporation losses are very small. The nutrient rich fish water flows through the tubes providing the plants with what they need.

A whole wall has been covered with these plant tubes and connected to large aquaponics fish tanks:

Photo by Kanu Hawaii.
The fish in my system are also pet fish and live in an ordinary aquarium, so that you can see the fish, but I don’t think the fish actually care whether or not they’re able to look back at the people watching them. And if that’s true you might as well dump the fish in a big black plastic container as shown in the picture above. Just remember that black surfaces absorb energy from the sun and  heat up.

An aquaponic system can be installed anywhere, like for instance right next to a restaurant or hotel to secure an extremely fresh supply of herbs and vegetables:


Photo by Kanu Hawaii.
The system I built is based on an ebook called Aquaponics 4 You that originated from Hawaii (formerly known as Ultimate Aquaponics Home System) and the University of Waimanalo in Hawaii is experimenting with aquaponics too. Take a look at one of their neat plant tanks, with floats and net pots installed, standing on top of a few layers of cinder blocks:


Photo by Kanu Hawaii.

The area is packed with aquaponics tanks, and a solar panel would be a very convenient way of driving your water pump in an outdoor aquaponic system:


Photo by Kanu Hawaii.
Some kind of marquee placed above your tanks would be a good way to protect your crop against the weather if it’s necessary:


Photo by Kanu Hawaii.
When you’re building a system and looking for aquaponic supplies you can benefit from all the hydroponic containers on the market already. The large white tank below is from genhydro.com but all the pipes and fittings you could ever dream of is probably also available from the existing hydroponic retailers:


Photo by Kanu Hawaii.
I grow my aquaponic plants in coconut fiber but many people use LECA balls instead (Lightweight Expanded Clay Aggregate) – then you won’t need floats and net pots:


Photo by Kanu Hawaii.
Here’s another system installed under a large polytunnel cover, with an artificial fish pond beneath the plant pond:

Photo by Justin Leonard.
The next system has three layers – two layers of watercress beds and a 120 cm deep fish pond (4 feet) at the bottom. The beds are 120 cm wide (4 feet):


Photo by Justin Leonard.
The water circulates slowly through PVC pipes and the watercress filters the water for the fish:


Photo by Justin Leonard.
You can throw as much money as you have at an aquaponics system to keep improving it, but with very little money and reused materials you can get a cheap system up and running. The most expensive part is probably the pump but in small systems it shouldn’t take long to find someone who has a spare that you can have for free.


Photo by hurricanemaine.

Aquaponics Plant Germination and Algae Eating Fish

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This is a box I have set up for plant germination of my aquaponic plants:

The red plastic plate under the lid is just for ventilation to provide oxygen for the seed germination process. I’m using 2 and 3 inch black plastic net pots (5 cm and 7.5 cm) for the aquaponics system, and I’m sowing directly into the net pots:

There are very few nutrients in the coconut fiber material so when the seedlings develop their first true leaves I move them into the aquaponic plant tank where the water is filled with nutrients. This is a good thing about an aquaponics system; you don’t have to replant your seedlings with risk of damaging the roots.

In the beginning I kept a journal of everything I sowed with a serial number on every pot, but it takes a long time to update and since I haven’t got that many different plants in the system I can usually see right away what type of plant I’m dealing with when the seedlings appear, so I won’t be updating the journal anymore. I’ll just focus my energy on getting a truckload of plants through the system instead ;-)

The fish in the aquarium connected to the plant tank are thriving. The interior of the tank is beginning to look like a natural environment, although we’re experiencing some really nasty looking algae, with a green synthetic like color. (If you know something about algae classification, please leave a comment below this blog post).

Fish tank and algae pictures:

But the fish seem to be okay with their artificial environment and fortunately they’re algae eating fish.

They’re pumping out fry, actually the third litter in one month. These are some of the blue acara fry, out of a litter of about 200(!):

The plants in the plant tank are doing well too. This is flat leaved parsley stretching for the grow light:

This strawberry plant did provide us with a few strawberries, and sent out a runner which I replanted in a new pot, but then it started to wilt:

I don’t know what happened – I’m sure I gave it enough water. (Get it?… enough water – in the aquaponics system?… Oh I crack myself up sometimes).

But then there’s the chives:

These are the workhorses in the system at the moment, with really long roots, and lots of them.

Note that both the strawberry plants and the chives are from the nursery where they were started in soil, which makes it hard to transfer to an aquaponics system, but we had to get some plants into the plant tank to clean the water for the fish as they where going into the aquarium no matter what. Or, at least Charlotte had a very good opportunity to buy tropical fish of the type she wanted at that particular time.

Both runner and bush beans are growing fast when they are plugged into the aquaponics system:

This is a bush bean type – runner beans are not practical in this particular system as the growing height above the plant tank is limited to 50 cm (20”) because the plant tank is placed just below the ceiling. I’m expecting a good yield from the bush beans and I’m looking forward to seeing the results. It seems like they are growing really well and we haven’t even done any adjustments of the pH value yet.

I can’t help dreaming about a nice big backyard aquaponics system, but after all it’s probably wise to get the basics right before scaling up the system.