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.
Step 1: Gather Supplies
- 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!)
- 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 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
* No coloring
* Gives roots something to bite into
* Retains moisture
Plan your system. Determine which side you want the reservoir on.
Step 2: Prepare the Growing Medium
Here's a photo of the medium, with a Canadian nickel (same size as US nickel) for scale.
Step 3: Install the Drains
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.
Step 4: Stack the Boxes
Step 5: Fill With Media
Step 6: Install Feed Lines
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.
Step 7: Prepare the Reservoir
Step 8: Build the Injection Manifold
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.
Step 9: Install Your Tees and Elbows
Attach the runner tubes coming from the center box.
Step 10: Build the Drain Manifold
Step 11: Create Drip Taps on the 3/8 Inch Tubing
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.
Step 12: Put in Your Plants, Fill, and Test!
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!
Step 13: Enjoy!
Top of your nutrient reservoir with a normal mix of nutrient.