Compact, Cheap, and Expandable Hydroponics System

Picture of Compact, Cheap, and Expandable Hydroponics System
I know there are a ton of other instructables out there that deal with hydroponics but I wanted mine to fulfill a certain set of specifications. When I sat down to design my new hydroponics system for my apartment I had a few goals in mind. The system had to be cheap, since I'm on a college kid on a college budget. The system also had to be expandable, just in case I wanted to add some new plants. I really liked the ebb and flow system since it can be powered by a cheap aquarium pump and does not have to run constantly. I thought of every-day, cheap, household items that I could use for the containers in an ebb and flow system. I also needed to be able to construct everything with very limited tools. I only had a dremel with various attachments, some pliers, and wire cutters. As a result, I came up with a complete ebb and flow system consisting of a three container system and pump for around $20. If more containers were desired, it would only cost around a dollar per container.

I wanted the system to be expandable but I was also pressed for space since I am living in a very small apartment with three other individuals. The final parameters were: the system had to be easily managed and easily transported. Easily managed because I'm sometimes lazy when it comes to upkeep and easily transported because the system is not going to be set up in a permanent residence; I will be moving at the end of the semester. Since my apartment receives very little lighting I decided to make a grow light stand as well. Since grow lights can get up into the hundreds of dollars, this adds quite a bit to the total cost of the project. Although this allows you to put your plants where ever you please, it is by no means necessary as long as you have sufficient lighting.
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zgezon3 years ago
Very cool design. I am building a similar set-up for a science project, but I need to make sure that all plants are getting the same solution, so I will have one large chamber (a 3 liter bottle) with 9 hoses coming out it. Each hose will connect to a small planter. I have not built it yet, but I foresee a potential issue I wanted to know how you got around it. I need the solution to drain back into the main chamber each time the air pump turns off so it can mix with the other solutions. I worry that the air pump will maintain pressure in the bottle, not allowing the solution to drain efficiently. Did you have this issue? If so, how did you get around it? Also, when you have it up and running, how far up your planters did you have the solution rise? Thanks!

How did it work out for you? Rather than nine hoses coming out of one resevoir, you can use one hose split into two using a three-way junction. Split that into two again, and those two into two again, and you have 8 equally-pressurised nutrient lines to feed into 8 or more planters.
Dandeman321 (author)  stormsaber1 year ago
You may be able to use some T's from drip irrigation systems
Dandeman321 (author)  zgezon3 years ago
For the level of solution, I turned the pump on, then added solution until it topped off each plant.

The way this design works, is that each plant has a sealed chamber with solution and two tubes. One for air, the other for solution/water. The solution/water tube goes straight up to the plant/gravel from the bottom of the chamber. The air tube blows air into the chamber, displacing the water, pushing it up through the solution/water tube, into the plant/gravel. When there is no solution left, the air goes though the tube, keeping all of the solution in the plant/gravel. When the pump turns off, the solution/water slowly drains back into the chamber since there is no air pressure keeping the solution/water in the plant/gravel.

I do not know of a way to have one single chamber for the solution/water unless you have a massive container (like an air tight storage container) and each plant/gravel container is on top of it.

Hope that helps.
stormsaber1 year ago
Brilliant system, very simply to design and build. I have created a similar, simpler system with good results after misunderstanding what you had written.

The system I have made uses one large resevoir - in this case a standard 2l soft drinks bottle. The air is pumped into the resevoir at the top like normal, and nutrient exits via a tube as in the OP's instructions. The only real difference is that the tube splits into two via a three-way junction and then in to two again via two more three-way junctions before entering the planters which are also 2l soft drinks bottles. Thus the system is highly modular and expandable in powers of 2. I was initially worried that the pressure would not hold when the nutrient gets to the planters because at this point it is under 1/4 the pressure it was when it left the resevoir. But I guess the water behind it aint going anyway so the water in front has no place else to go and happily pools up into the planters. It is working fine for four planters and I would be prepared to believe that eight may work as well. I don't know what the limiting factor is, probably the size of the reservoir - but it seems even this tiny pump can handle air pressure equal to the weight of two litres of water. I'd also imagine the containers would not have to be at the same height, as long as the lengths of tubing on either side of the junctions are symmetrical.

As with Dandeman's setup it is still quite hard to regulate bubbles in this setup and I'm not sure what the limitting factor is. When the reservoir is empty and the planters full the bubbles seem to pick a left/right direction at each junction fairly arbitrarily and I don't know if that depressurises that line or what - the other three planters stay full, and one bubbles away. Perodically the bubbling planter will change for some reason and another will start bubbling but not with any regularity or predictability.

PROBLEM: The problem I am having at the moment is that even though I bought the cheapest pump I could reasonably find, it is too advanced for this project. It has a back-flow valve in it which prevents air (and hence water) from going back through the pump when the power is off - presumably to stop an aquarium from siphoning all its water onto the floor through the pump in the event of a power failure. Of course, that's not a problem for us - but the valve stops the planters from draining as the reservoir remains pressurised even when the power to the pump is off. What can be done about this problem?

Someone on another forum (I think it was youtube?) said he solved this problem by using a needle to make a tiny hole in the air line. This slowed down the speed at which the planters filled, but increased the speed they drained. I don't want to do that, it seems like an inelegant and inefficient solution to me.

In conclusion thanks for a great and helpful instructable. Any assistance that could be given regarding reservoir pressurisation would be appreciated!
Dandeman321 (author)  stormsaber1 year ago
Great idea with the big reservoir! That way each plant will get the same amount of water as it floods. Only downside is you can't keep nutrients separate so if you're flowering tomatoes in one, you don't want to flower your basil in the other. Yeah, not sure what to do about that backflow. A pinhole may be the best way to solve that :/ Glad you got use out of the instructable! Thanks for the suggestions!
cogworkz2 years ago
Alternate solution.

The problem you're having is due to the fact that the liquid in the system serves as the seal. If it starts to bubble, the seal is lost and the system depressurizes and the units downstream do not ebb and flow. This is only problematic because you're trying to pressurize the system in series.

Instead of messing around with the solution levels in each unit, you could instead use an aquarium air distributor to pressurize each unit independently. (This also does away with the need to have both an input and an output on each container).

For example, the distributor I'm going to link can independently pressurize 4 units without messing around with the water levels:

The only caveat is - the amount of liquid in each reservoir will need to be equal., since they will all pressurize at the same time. If bubbling occurs in one before the others, it will still cause the system to depressurize. But I think what I've suggested here should simplify both the design and the effort to equalize the pressure across containers.
Dandeman321 (author)  cogworkz2 years ago
Yeah getting rid of some of the seals would help out. And yeah, I did notice the balancing water problem. Gotta keep them all equal. I've abandoned this system and moving on to a larger setup.
I figured you would - the obvious problem I see with this set up is how frequently you would have to replace the solution. As plants get bigger, they get hungrier. So it wouldn't be long before tending to this system could take quite a bit of work. ;)
Dandeman321 (author)  cogworkz2 years ago
Exactly. This system was designed to be small and cheap. Not really too useful if you grow larger plants in it.
Actually, they don't have to be equal, since each port on the distributor has an adjustment knob. So rather than adjusting the level of solution you can adjust the flow rate of the air going into the container instead (by twisting the knobs).

This ability to adjust flow rate to each container could also let you use multiple size containers with the same pump. (Turn the flow rate up on a big container, and down on a small container until you the displacement rate works for all containers... just dial it in).
jerry583 years ago
how much does this project cost to make????????????

Dandeman321 (author)  jerry583 years ago
The instructable clearly shows how much it costs.
jimmy0053 years ago
i gbot a question here, what sort of aquarium pump do you need? a pump for air?or a pump for water?
Dandeman321 (author)  jimmy0053 years ago
thanx!! :D
Dandeman321 (author)  jimmy0053 years ago
Tyler5205 years ago
it would be nice to find a way to make the netire system passive (no pump). A lot of people use wicks, but the wick ends up absorbing a lot of the nutrients before it gets to the roots.

Algae is also another problem...might want to paint the water reservoir opaque.
sires65 years ago
One more thought, Dande, is that you might be able to negate some of your problems by having some kind of drainback system.  A stiff tube fitted through the plant reservoir to the nutrient reservoir below the level of where the air will bubble through might help.  Or another tube fitted up through the cap???  I am imagining two tubes fitted through the cap???  Just a thought looking at other ebb and flow designs in google.
Dandeman321 (author)  sires65 years ago
If there is a tube going down to the water it would shoot up through the tube. If the tube is just a drain, then all of the air pressure will be let out. I think I understand what you're saying but I think that one would still fill up quicker and loose pressure for the rest of the system.
I understand what you are saying.  It might be worth a try with a one-plant system, to see what might happen.   No, the more I think about it, you have to have a kind of drain-back hose... You could try a larger size one that only comes out just inside the bottle.  I don't think you'd lose air pressure because the system is closed off with the water in the bottom of the drain tube.  And it would form a  closed system.  Initial start-up would have water coming up both, maybe, but having the drain-back lower than the in-flow would form circulation?  You could form it without plants to try.  Just a thought.  Your inflow would have to be a little faster than out flow to allow for filling of the upper reservoir.  Mmm, I'm not sure.  It was just a thought.
Dandeman321 (author)  sires65 years ago
Yeah, it may work. Or a water pump could be used, instead of the air pump, to suck water from the reservoirs and spit it out back up top.
coco j5 years ago
is there anything easier then this for the light system?
Dandeman321 (author)  coco j5 years ago
Use natural light from outside.
Only problem with "natural light" is that if you are growing during the winter or colder times, especially if you live in Northern Climates like New England or Germany (where I did), you don't have enough light coming in during the day and the light cycle is too short to actually grow plants.  Go to Walmart and buy a cheap $10 light fixture for flourescent lights and buy grow lights.  AS for the PVC light stand, you can get used PVC from plumbers and construction sites for free.  Just ask.
Dandeman321 (author)  sires65 years ago
Yeah, that's true about the natural light.
kathy15835 years ago
Thanks soooo much! I'm going to try this system with the grade schoolers. They will love this! Thanks for such a great and simple idea. It will be very minimal cost for the kids, since most of the items they can problably find at home.
Dandeman321 (author)  kathy15835 years ago
No problem! Hope it works out alright.
kathy15835 years ago
I love your idea for a small home system. I want to teach the grade schoolers how to make this type. What kind of tray did you use? Also, does the pump lead to another container or is it underneath the one in your photos? Do the containers connect with a piece of hose between each of the straight connectors or just from one connector to the next straight connector? And finally, how much water did you start with and how often do you add to the level? Can't wait to try this with the kids!!!! Thank you, thank you, thank you!
Dandeman321 (author)  kathy15835 years ago
At the hydroponics store, they had some cheap black trays. I just picked one of those up. The pump I have is in the tray, it's just a small aquarium pump. I would use 1 pump per container though, since I've had problems when I've hooked multiple containers up. There just isn't enough pressure to push the water all the way up in multiple containers. It just ends up bubbling through one. For the water, I mixed up some of the nutrient solution and poured a bit in the bottom. I then turned the pump on and just adjusted the level until it was slightly above the expanded clay/gravel. Hope this helps! Glad you're using it! You should post some pictures when you get them all setup!
coco j5 years ago
where are these kind of stores at?
Dandeman321 (author)  coco j5 years ago
Use google. I just noticed mine on the way home from work one day.
coco j5 years ago
and is there any way i can make the wholes without the tools?
Dandeman321 (author)  coco j5 years ago
You could heat up a nail and melt through it.
coco j5 years ago
do u guys happen to have a more simpler way for me to understand how to make one of these, you know like for dummies? lol!
jrossetti5 years ago
This is a pretty ingenious system you've designed here. I suppose there's a theoretical limit in the number of containers you can connect, based on pump output. I've seen higher output pumps, though, with 2 and 3 output nozzles, so I suspect it's possible to have a huge network of containers. This is one of those ideas I'm definitely going to have to try. Thanks!
Dandeman321 (author)  jrossetti5 years ago
Well I later found out that it is difficult to balance the amount of water in each module so that all of them will bubble. Usually one fills up and starts bubbling and then the air pressure in the network drops and does not push any more water in the other ones. I pump with multiple outputs, each hooked up to one module, would work very well.
Yes, I figured this out too last night. The problem is the low pressure output from the air pump, I believe. It's possible to add a second air pump and put airstones in the base of each of the upper containers, but I feel that overcomplicates the whole system. As it is now, it's simple and elegant - and elegant in its simplicity! I think forcing it to bubble isn't terribly critical in a system this small, and since each plant has its own reservoir, that makes it exceedingly easy to correct any problems with aeration or with the nutrient solution. I've set mine up with 3 plants total: one in hydroton, one in perlite, and one as a soil-based system. I will keep you updated how they all fare.
Dandeman321 (author)  jrossetti5 years ago
Very cool! Yeah, I thought that more air pressure may help but I'm unsure. It is really simple! That's how I tried to design it. I didn't want containers that would take a lot of effort to create and I wanted to make them cheaply. I wouldn't know if the plants would die without bubbling since I killed mine accidentally :( Yeah! Let me know how they work out! Hope they do well!
hithisishal5 years ago
Thanks for the instructable! I'm thinking about building one myself, and growing a similar selection of herbs (probably parsely, basil, and cilantro). I have two questions for you: First, how are they doing? Still alive? Growing well? Second, I was wondering what your "flooding" schedule is. Have you found if you get results in the closer to 2 or closer to 5 range? Are you supposed to flood more if they air is dry (and the plant dries out faster) ? Is there anything else you can say about that?
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