Best Damn Organic Recycled Solar Pump Hydroponic System

A hydroponic system that is made from trash and incorporates an electric solar pump to supercharge your growth?! Wow!

Here's a modular and lightweight rooftop setup. You can also place it anywhere that you have full sunlight, and no earth--like a parking lot!

This is the third revision of this model. It's cheaper, has a larger reservoirs, and the reservoirs are self-leveling.

Total cost for a single "pod" (two are shown in the below photo) is under $45USD.

Please post comments about success or failure you've had with this system.

You will need a few things:

• 5 x Styrofoam "fish boxes" (approx 18"x40"x18 WxLxH), two with lids (FREE!)
• 20L (5gal) plastic bucket (FREE!)
• Solar pump (cheapies on eBay for $15)
• 16' of 3/8" poly tubing for drip irrigation (about $10)
• 2 x 3/8" tee
• 2 x 3/8" elbows
• 3 x 1/2" drain fittings, sometimes called bulkheads ($10)
• 16 x 1/4" drip tubing "taps" which are punched into the poly tubing ($10)
• Growing medium that doesn't clog (Coconut husk chunks work great!) ($10)
• Mesh screen (FREE!) use a broken screen door
• A stone to weigh down the reservoir lids (FREE!)

You will need the following tools:

• Power drill
• 3/8" drill bit for drilling holes in styrofoam for poly tubing
• 3/4" drill bit for drilling holes in styrofoam for drain (bulkhead) fittings
• Sharp screw or other poking tool for making pilot holes in poly tubing for the drip taps that feed each plant

The styrofoam fish boxes can be found in the dumpsters of seafood stores. They are used to ship large salmon, etc, and are usually thrown out back. Be sure to check for leaks, as they need to be water-tight.

The buckets can be found at sandwhich shops. They are used to ship pickles.

The solar pumps are found on eBay.

The drip tubing and fittings can be found at hydroponics stores, or home improvement centers (Home Depot, Lowe's) in many regions.

The 1/2" drain fittings, or bulkheads, can be hard to source. Hydroponics stores will be your best bet.

For a growing medium you can use wood chips. I use coconut husk, which is rather chunky and was on sale for $0.50/cubic foot.

Criterion for media:
* Large sized, so it won't wash into drains, tubes, and pump
* Absorbent
* Cheap
* Inert
* No coloring
* Gives roots something to bite into
* Retains moisture

Plan your system. Determine which side you want the reservoir on.

If you are using coconut product, soak it in buckets of water for a few hours to break apart the compressed bricks and to clear any residual salt (a byproduct of the manufacturing process). This also gets rid of small particles that can clog the filters or the pump.

Here's a photo of the medium, with a Canadian nickel (same size as US nickel) for scale.

Three out of the five boxes will have drains installed in the sides, at the same level. Later, we will elevate 3 of the 4 boxes, using the 4th one as a stand. This difference in height allows the fluid to run out of the drains in the top boxes and back into the reservoir to be recirculated. The 5th box is the reservoir. 

Use your drill and 3/4" bit to drill your drain fitting holes. Place a drain fitting through each box from the inside. Make sure that the drain fitting is far enough above the bottom of the boxes so that the curve of the stryrofoam doesn't affect the seal around the drain (there's a rubber grommet there). The liquid level will be have to be about 1.5" deep before it starts flowing through the drain. This is your safety net in case the pump fails; there will always be a layer of liquid at the bottom of each styrofoam bin. The roots of the plants will wick up moisture from this layer.

Jam some of the screen door material into the drain openings on the inside of the boxes to prevent future clogging.

Stack 3 boxes on top of the 4th box. They should be perpendicular to the 4th box, with the drain outlets facing the reservoir.

Fill the 3 boxes with media. It should be about 5 inches deep. Leave a few inches of empty space above the media. This will provide the plants some protection from wind in early spring.

Here we will install in each plant box the 3/8" tubing that runs the length of the box.

Drill two 3/8" holes just above the media on opposing sides (lengthwise) of each of the media-filled boxes. Pass the tubing through the first hole and feed it out the other.

In this system, the irrigation and drain tubes are on the same side. On the opposite side, you'll need to have 3" extra of poly tubing so that you can bend the tube back on itself and secure it with a cable tie, making them leak-proof.

Test the reservoir to make sure it will hold water. Holes only need to be drilled in the top for the drain tube and the pump outlet which connects to the irrigation tubes up above.

Here we will build the system of tubing required to bring fluid from the pump inside the reservoir to the runner tubes in each box.

Install a piece of poly tubing that is long enough to touch the bottom of the reservoir, and extends about 8 inches above the top of the bucket. This is your main feed line from the pump.

Next, place your reservoir bucket next to the styrofoam bin system, and cut the main feed line at the height where it lines up with the tubing on the middle box. Install a tee on the end of this feed line.

Install an elbow on the ends of the poly tubing in the outer bins.
Attach the runner tubes coming from the center box.

Here we use the larger 1/2" rubber tubing to connect all of the drains from the boxes so that they drain into the reservoir.

Use a tool to puncture the tubing. Since you are going to have plants on both sides of the 3/8" tubing, it is wise to make your holes angled slightly downward, to keep nutrient from dripping back along the underside of the nozzles.

After making a puncture with the tool, push the drip nozzles into the holes that you made in the 1/2" tubing.  Put a drip nozzle at the base of each plant.

Transplant your plants. It is best to put established plants into this system. Plant in the evening when the sun is not as strong and the plants can adjust overnight. The courseness of the medium is not appropriate for starting from seed, unless you want to grow some lettuce as seen in the picture. You can just drizzle the seeds in between the larger plants.

Fill the reservoir bucket hydroponic nutrient mixed accoring to the directions on the bottle. You can probably use standard fertilizer from a home improvement store if it has micronutrients.

Place the solar panel somewhere where it will get full sun all day long.

Plug the pump into the solar panel, and watch it run!

Congratulations! That's it. Now you have a free-flowing solar-powered hydroponic garden that is simple to maintain, and gives plants tons of nutrients directly. Best of all, you don't have to invest in any expensive HID lighting; you're using the power of the sun!

Top of your nutrient reservoir with a normal mix of nutrient.