Step 1: The Idea
Along with the water pump, my system uses gravity to assist the flow of water. Each end of the PVC is one inch higher than the end that comes next in the circle. The end of the tube that water enters from is the highest, and the end that it leaves from is the lowest. To achieve this, I built supports out of lumber for the pipes. The supports also keep them high enough to be above the reservoir, so that gravity will return the water to it.
Step 2: Materials
- 66" of 4" PVC Pipe - If I didn't already have PVC, I would have probably bought plastic gutters.
- Assorted lumber - Go to the cull wood section of your hardware store. This is the wood they cut for other people who didn't want the scraps. I got four 43" 2x4"s, one 1.5x7.5x58" piece, and a scrap of plywood for $3.
- Screws and such
- 4 rubber adjustable end caps with hose clamps - about $3 each
- Submersible pump - I'm using this
- Teflon tape
- 16 oz Plastic cups
- Irrigation tubing
- Opaque Bucket
- Plumbing cement
- Growing medium - I used expanded clay ball
- Hydroponics Nutrient
Step 3: Build the stands
I'll assume you've already cut the PVC in half...it doesn't really deserve it's own step.
Next, I attached them together with the 2x4's. I found out the hard way that it's easier to make them level if you attach the 2x4's mid way up, instead of at the bottom.
Step 4: Plumbing
My pump came with a removable attachment for the tubing, so I wrapped one side of it with Teflon tape and used plumbing cement to attach it to a piece of tubing long enough to reach from the upper tube to the bottom of the reservoir. I then pushed the tube through an end cap's hole. Push another piece long enough to reach from the lower tube to the reservoir. Then attach two end caps via tubing long enough to fit on both pieces of PVC.
When I tested the system like this, it ran surprisingly well, with a just a few small leaks. Use the plumbing cement to seal around the outside of all the tubes. Plumbing cement isn't the most safe substance (toxicity wise), and even though it's probably OK, by just sealing the outside, it at least makes me feel better about. Luckily this stuff cures in two hours, so you can do another test run pretty quickly.
A lot of people recommend cleaning everything with a heavily diluted bleach solution to help ward off algae. I did this before I had drilled any holes. It was easy to fill the pipes and then shake them with the end caps on.
Step 5: Holes
We have an adjustable door knob drill bit that drills holes up to 3" wide, so I cut a skewer to 3" and found where on my plastic cups they have that diameter. Hold it up to the PVC and see if it's deep enough. It was. Unfortunately, the only drill we have with a chuck that could fit that bit was a hand drill. At first I tried the "drill a whole every millimeter and cut it out" method...but I didn't have the patience. Instead, I used a 2.5" drill bit and sanded the rest down with my Dremel. If you have to use a Dremel on plastic, make sure to wear a mask in a well ventilated area and clean up all the dust afterward.
Rinse the dust off of the pipes.
Step 6: Assemble
I drilled three holes in the lid to my bucket, one for the intake tube, one for the output tube, and one for the power cord. It allows me to leave the lid on, and thus help prevent algae from growing.
Step 7: Cups
Use the cups to measure out clay balls into a bucket of water. The water will wash off any dust that has accumulated on them.
Step 8: Planting
When you're arranging the plants in the system, keep in mind what kind of plant they are. Put taller plants in the back, so they don't block the sun. My plants that grow heavier veggies are on the lower section, so that I can build a table from the plywood and 2x4's to support their crops.
Step 9: Nutrients
- Nutrient solutions come in all sorts of varieties. I bought a general purpose "grow" solution that also has a "bloom" counterpart for when the plant begins to...bloom.
Step 10: Maitenance
Hydroponics.net recommends that you add fresh water as it's used by plants, because even though water is absorbed, nutrients still remain, and can get more concentrated. They said that once you've added half the amount that was originally in there, it's time to change. So with my 7L, once i've had to add 3.5L of additional fresh water, the nutrients will be mostly depleted.
Some people also monitor their ph levels. Pool stores generally will check it for free. I don't have a lot of information on the subject to offer, however.
Other than that, there isn't a lot that you have to do except care for the plants as you usually would.