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.
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Signing UpStep 1Gather 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
* Absorbent
* Cheap
* Inert
* No coloring
* Gives roots something to bite into
* Retains moisture
Plan your system. Determine which side you want the reservoir on.
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As a matter of fact the design was changed this year! I'm using styrofoam bins as reservoirs instead of buckets, as each holds about 2.5 buckets of nutrient. The reservoirs were placed as close as possible to the edge of the roof (they are reversed in contrast to the current pictures) to reduce weight on unsupported portions of the roof.
I'm concerned about using the support stand boxes for holding nutrient solution, too, because of the weight. My landlord has been very kind to allow me to use the roof for this project, and I'd hate to jeopardize that good will.
As you also suggested, I'll be daisy chaining the styrofoam reservoirs so that they self equalize.
Updated pictures to come!
Oh, and I think you meant "evaporation"?
I'd love to see your system, but for a small-scale system, it seems like over-kill.