by Tim
“Office” Hydroponic System
10:43 am in Featured Post, Projects in Process by Tim
A co-worker and I set up a system at work at my cubicle. We used 1.5 liter plastic Coca-Cola bottles. They were first wrapped with black electrical tape and then aluminum ducting tape to keep the light from the roots.
As far as the air lift system, I purchased a $6 air pump from Walmart. The air line setup that we came up with does not need any special parts or fittings other than a “T” and a valve.
All of these items I had lying around and so far have only spent $6! I will update later on the progress and what else we used/added.
Our other co-workers have stopped by to look at our setup and have wondered what it is. We’ll keep them guessing. 
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- I chose to use plastic Coca-Cola bottles due to the proper shape. The Coke bottle design is perfect due to the “hip” and inward curve to allow dripping water to naturally drain towards the center of the bottle.
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- First step in blocking light from root growing area.
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- In order to cover the curved surfaces, aluminum tape strips were made.
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- Aluminum duct tape cut to proper lengths.
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- View inside to show the the root growing area has no light getting in.
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- Second step in blocking light from root growing area.
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- Bottles connected
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- This is the first day. Seeds are in starter pads in each of the three growing bottles.
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- This airlift has just a line fed from the bottom of the reservoir coming out of the fill hole. It hangs down and connects to a valve, then a “T” to the top of the system.
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- Basil sprout after 5 days.
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- Tomato sprouts after 7 days.
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- Removed the “T” at the top bottle that was being used to disperse the incoming liquid with this spray nozzle. I enlarged the hole attached it to the incoming line and aimed it towards the back of the bottle. This eliminated the messy spray coming out of the top bottle opening that the “T” was making.
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- Cilantro finally came up this week.
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- One big tomato plant and one that is having a little trouble, but all in all doing well.
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- Original basil seeds got washed out of the center of the grow cube, but took root on the sides. Planted new seeds and they started in the center.
Awesome work. I assume your cubes are near a window?
MINE is.
I’ve got an Aerogarden 3 at work that pretty much generates the same reactions. I am sadly too far from the windows for a windowfarm at work.
I like the way you wrapped your bottles. Very neat.
It’s been 5 days. Came in this morning to find a basil sprout starting.
After 7 days, we now have tomato sprouts. We are still waiting for those cilantro seeds to pop.
Cilantro is 7-10 days. I wouldn’t worry until the 2 week mark. I’ve read they have two embryos inside so you should get two plants from one seed (or at the very least one).
Cilantro leaves showed themselves yesterday plus new basil leaves.
I’m still not fully understanding airlifts. What’s keeping the air from going straight up at the T joint without pulling any water with it?
Ohh, wait. I might have figured it out… because it’s below the entire reservoir, is it pulling just enough to get gravity involved kind of like with siphoning gas? That would give me more questions to ask to understand all of it but it’s a step up from being completely clueless.
I think air-lift works due to the cohesive nature of water and other factors. Aquarium air-pumps actually works with a physical bellows puffing away, thus it is not a continuous supply of air. Some water will be trapped between each puff and if the tube is narrow enough, water cohesion will not allow the air bubble through, thus the bubble has to carry the water all the way up the tube. The deeper your t-joint is, the greater the water pressure to force water between the air bubbles, creating bigger water packets which prevents the air from breaking through.
This is just my personal hypothesis. Not based on any scientific research or experimentation.
Or rather, what the t-joint is is an aerator that mixes air with water. Air comes in from one inlet and water in the other. So even if the air is continuous, like from a gas canister, if the pressure of the water inlet is comparable to the air, I’m sure they will mix up the tube. That is why immersing the aerator deeper will give you more water pressure, and also reducing the pump helps. I think it’s about getting the pressures to get a right mix.
@Tim, btw did you use net pots? I’m contemplating not to but experience of some others said the roots ended up clogging the bottle cap.
Can you explain the nozzle you used to disperse the fluid? 12th picture
So exciting! Thanks for sharing/
There’s also vacuum pressure involved. If you are interested in the physics, you can read on wikipedia about aspirators, airlifts, cappilary action, the Venturi effect, and Bernouli’s Principle on Wikipedia!!
Wow! This looks fantastic and fun. What I’m curious about is the following:
1) Will this work on a much smaller scale – such as a single bottle?
2) Are the pumps relatively quiet/silent? I know from fishtank experience, they vary. Any recommendations for an office pump for silence?
3) I have a fluorescent array immediately above my desk (ceiling), which is on during the normal business hours (8am to 6pm). I also have localized under-cabinet fluorescent strips I can turn on and off. Are these useful for growing, or do you have to place these near a window for actual sunlight?
4) I do not have a green-thumb, but I suspect this is due to improper watering and feeding techniques employed. Does this system effectively allow me to keep a plant happy with little effort?
Thanks!
I really like the root cover idea. Although I think just using the aluminum tape strips would have been enough without the extra layer of electrical tape.
Any chance you could upload the construction video to youtube? My Quicktime isn’t cooperating.