Introduction: Recirculating Hydroponics
This unit allows for long term growth of large plants. There have been several hydroponic posts here in the past, but they all shared the limitations of either small plants or short term growth. This unit can grow a large plant practically indefinitely.
Step 1: Parts
You will need
Two stackable containers
A small fountain pump
1/2 inch pvc pipe , two elbow fittings, a threaded end cap and plug.
Clear vinyl tubing to fit your pump
plastic window screening
hole saw and drill
and anything i forgot.
Step 2: The Containers
Primarily, you'll need two qualities in your containers, when they stack, there needs to be a lip around the edge of the container to contain our nutrient solution, secondly they need to be ridged enough to support the weight of the system.
The two containers I'm using are dog food containers (food safe plastic) of about 8 gallons capacity. We'll clean up the algae later.
To prep the bottom container. Take the lid of the bottom container and drill several holes into it using a 1 inch hole saw, then snap the lid on and drill a hole in the side of the container just below the lid line. that's that.
To prep the top container. Drill several holes into the bottom of the top container and two holes in line along the top edge of the container, Then snip them to make notches. Now cut a piece of window screen sufficient to cover the bottom of the container.
At this point wash the containers with a 10 percent bleach solution to remove dirt and algae.
Step 3: The Pump and Spray Bar.
We'll be building the spray bar in place to make sure it's right. stack the two containers. cut a piece of 1/2 inch pvc to sit in the notches cut in the top container, leave a couple of inches over hang for fitting attachment. cut a second piece and add an elbow, stick it in the hole in the side of the bottom bucket and now just cut a piece of pvc that will join those two pieces together. Add the end cap to the top piece and screw in the plug.
Now drill a bunch of 1/8 inch holes into the pipe across the top bucket to create the spray bar. Split the end going into the bottom bucket with a hacksaw about 1.5 inches.
The pump is attached to the spray bar with a piece of clear vinyl tubing, fortuitously the vinyl pipe slipped right into the pvc, the split lets me cinch it tight with a zip tie.
Step 4: Assembly and Planting
The bottom container is filled with nutrient solution, the pump and spray bar fitted into place through the hole in the side. Snap the top on and place the second container on top and fit the piece of window screening in to it and fill with washed perlite. The spray bar has enough play that it can be swung up and lifted into the notches cut in the top container.
Wash as much soil as possible from the roots of your plants before planting, otherwise follow general planting procedures, ie not to deep, not to shallow.
Place the unit in the sun and plug in.
To change nutrient solution (about every ten days) unscrew the plug and let the solution get pumped out, I catch it in a bucket to water containers. Mix up a new solution (Gen Hydro is very good) and slowly pour it in through the top of the perlite, optionally remove the top container and fill directly.
The unused lid from the upper container can be drilled and split to surround the plants, this limits contamination of the perlite by organic matter (leaves mostly) and algae growth.