I have been interested in hydroponics, aquaponics, aquaculture, Barrelponics and other related topics for years now. Finding room and time for all my other projects has always kept me from doing more. Mostly I research and read books. However, when I went to gardenpool.org and saw their brilliant idea for “shelfponics” I was hooked. When a week later I found a cheap fish tank at the goodwill I saw it as a sign to get off my * and try this out.
Like gardenpool, I went to the local big chain DIY store and bought a $15 plastic shelf system. It was only 4 shelves and some plastic pipe. While I was there I also bought a electric timer for $12. It is the kind that has 48 little switches so you can program the timer in 30 minute increments over a 24 hour period. I flipped every other one to “on”.
The next step was to go to my local hippy store (brew shop/aquaponics supply/cheese making supply/organic store) and buy the fittings and miscellaneous parts.
- 5 ft of flexible hose
- 5 ft of semi rigid hose
- 4 T-fittings, an elbow
- 6 hose clamps
- An air stone
- Air hose
- Air pump
- 190 GPM water pump (which according to gardenpool is too strong, but its all I could find)
- Rockwool growing cubes so that my small lettuce seeds could sprout and not be washed away by the flowing water.
Assembly was pretty easy:
I assembled the first shelf normally for the aquarium to sit on. Next I flipped each subsequent shelf upside down so that the molding would make a grow bed.
I then took some aviation snips and cut out some of the internal molding lines that gave the shelf some strength. This was to channel the water inside the shelf. The plastic was very brittle. I found that if I cut it too closely to the “bottom” of the shelf it cracked the shelf. On the occasions that happened that is where I drilled out the drainage hole.
Once the water channels were cut, I drilled holes for the T-fittings to allow some drainage. I used 100% silicon around the fittings to ensure the water only flows where I want it to. At each fitting, I connected about 8 inches of the flexible hose to the leg of the fitting that passed through the shelf. That way the drainage from each level of the shelf can be directed straight to the next lower shelf. This is instead of free falling and splashing on my wall.
I attached my rigid line to the pump. Next, I placed the pump in the aquarium on the bottom shelf. The line ran up the side of the shelf to the top grow bed. Once there I attached the elbow, and then clamped on about 6 inches of flexible hose to the other end of the elbow.
Later I may have to add some sort of pressure reducer or drip line, but time will tell.
At this point, I added water to the aquarium. However, I did not add fish wet. This is because the water needs about three days to let the chlorine dissipate.
I am also taking this time to let the silicon sealant harden before I add the hydroton.
How it Works
The idea is that once I add the hydroton and the rock-wool cubes of lettuce, leafy herbs, and a few (4) pole bean plants, I will plug up the water pump. This will create an ebb and flow hydroponic system where the water will be pumped up to the top shelf and gradually drain down each shelf level until it drains back to the aquarium. By adding the fish I make a circular system.
The ammonia and other fish wastes would eventually build up and kill the fish without a filter, and the plants would eventually die if not fed. However there are certain bacteria that naturally occur that turn the ammonia and fish waste into a form of nitrogen the plants can use. (Beans have this bacterium in their root systems so I am adding them as an experiment). So the fish feed the plants, and the plants act as a filter to keep the fish alive.
I have about $75 dollars in this system, but I had to buy everything except the silicon sealant. If you use a little ingenuity, and scrounge you can make this MUCH cheaper.