The more people we have on this planet, the more food we need. Naturally, this extends to water, another precious resource that generally plays a part in farming and food production. And honestly, we’d probably all eat 
a little better if it were really easy to grow healthy things like spinach. Well, that excuse doesn’t work anymore, thanks to [J Gleyzes]’ Ultratower. It’s a simple-to-use hydroponic tower that uses recycled mist to water plants, ultimately saving water in the process.
The ‘ultra’ part is a function of the way mist is created. In this case, it’s done with three piezoelectric disks mounted under a tank in the top of the PVC tube. Stick up to twelve plants in the little cubbies, and their roots will grow down the inside, where they’ll receive a fine shower of water at your command. Water that runs off the roots collects in a small tank at the bottom, where a pump starts the process over again.
At first, [J Gleyzes] had trouble with the piezo disks — using 1.7MHz disks created too much heat, warming the water up to nearly 40°C (104°F). Since cooking the spinach prematurely would be bad, they experimented with other values, finally landing on 108KHz. Be sure to check out the video after the break.
Hmm. I like the concept, but I’d be afraid that the plants will need more than pure water, and whatever nutrients dissolved in the water will eventually build up a crusty deposit on the disk or clog the micro-pores.
I use fogponics (more common name for this type of hydroponics) in my seedling growout box. It’s very effective at getting growth. The particle size in the fog is smaller than the root pores, so the plants spend minimal energy on nutrient uptake.
The piezo discs do get crudded up. Regular cleaning by running them in a acidic solution (I use vinegar) does extend their life, but at the end of the day they are a wear item.
There are 2 things that I think would benefit this project.
1) A simple light transmission particulate sensor. If this is supposed to be fairly hands off, knowing when the fog output drops is important to know when to clean the piezos. Time based cleaning would also help. If you wanted to get fancy you could figure out something based on the attenuation of the wifi from the esp32 over the length of the tower, especially if you put it on 2.4ghz channels.
2) A slow speed low volume circulation fan. You don’t want the roots waving in the breeze, but enough air movement to carry the fog the whole way down the tower, and additionally keep the roots from staying too wet.
Yes you need nutrients, at the moment I am at 1.5 EC, there is a concentration sensor on the PCB to know the concentration of the solution.
Thanks for the improvement ideas, to know if the discs make fog I was thinking of either adding a humidity sensor in the tower but I’m afraid it won’t work for long, or putting a current sensor on the PCB maybe we can see a difference in current depending on the amount of fog (not yet tested).
For the fan, I’m trying to reduce the power consumption of this project as much as possible, that’s why I use electric piezo disks. Since the fog is created at the top of the tower, it falls by gravity to the bottom. I don’t think the fan is necessary.
Yes you need nutrients, at the moment I am at 1.5 EC, there is a concentration sensor on the PCB.
Thanks for the improvement ideas, to know if the disks are fogging I was thinking of either adding a humidity sensor in the tower but I’m afraid it won’t work for long, or putting a current sensor on the PCB, maybe we can see a difference in current depending on the fog quantity (not yet tested).
For the fan, I’m trying to reduce the power consumption of this project as much as possible, that’s why I use electric piezo disks. The disks are at the top of the tower so the fog goes down by gravity. I don’t think the fan is necessary.
On a vertical system like this, does mist offer any benefits over just having water trickling from the top? Because, by the time the roots on the top couple of plants have developed, that’s all the rest will get anyway.
Rainfall towers have been done, and seem to work well, but I haven’t done one so I can’t say anything for sure.
In my NFT channels, at the end of a growing season the roots pack the channels. Going larger in channel size might help.
Thank you for the improvement ideas!
To know when to change the disks I was thinking of putting a humidity sensor but I don’t think it will last long or putting a current sensor on the PCB maybe the current is linked to the amount of fog (not yet tested).
For the fan, the fog is created at the top of the tower and descends by gravity. I don’t think a fan is needed.
If there is a resonant component to the piezo drive, ypu could monitor the frequency. A crudded up disk is going to have a lower resonant frequency than a clean one.
You might also have a shake off after each fluid event, where you run the disk dry a little after each droplet event.
Yes, exactly, and I think that older discs have a slightly lower optimum frequency. We could even adapt the frequency according to the disc
I love this! You mention in the logs that the water level sensor has issues with corrosion – have you considered something mechanical, in a similar style to a toilet float?
so… it’s a bong for plants?
When all you have is a hammer, every problem looks like…
Would fall over and sink into swamp under the weight of a healthy plant.
I average 2 pounds of dry bud/plant. Don’t know what to do with all of it. Got 5 pounds left from last year and a whole new crop. Actually a little nervous regarding legal possession weight limits. Can’t smoke fast enough, tolerance like Willie Nelson.
He’s got plenty of room. Why not grow in dirt? KISS.
Put fish in bottom for ‘complete’ eco system.
Not sure how this is worthy of a prize. Nothing new here. Hydroponics is nothing new
Not sure why the Higgs Boson discovery deserved a Nobel. Particles are nothing new
silly discussion strategy there. The knowledge of the higgs boson is new.
How is this more efficient than a traditional setup with flat trays?
If I understand the concept correctly, less fuss pumping nutrients about since gravity does most of that work. Less footprint per square of plant or more plant per sqft of space.
Usually the benefits of going vertical are about plants/area. My NFT trays are set up in layers, so I get the benefits of density without having to troubleshoot a new hydroponic technique. I am limited by the head pressure my pump develops, and also by comfortable harvest height.
Sun is free. Hopefully your crop is legal now.
Just drip in dirt. KISS. Haven’t checked a nutrient solution in decades. Yes you can’t fix screwups as quick as hydro, don’t screwup.
Am wondering about the pump used. Small pumps seldomly have the power t transport water up high very much.
The project is a bit unclear about the top reservoir: does the piezo disc just lay in it with the mist overflowing some open edge?
Not up to me to decide if this is price worthy. DIY designs like this have been around for at least a decade (google PVC hydroponics tower): i built one in 2014, albeit with water just trickling down, which i later changed into the water being sprayed with a few of those cheap garden rotational spray heads. Had not seen this with a piezo disc yet though i have seen piezo discs in a Kratky set up
The pump used is a 5V pump found on aliexpress (it took me a while to find the right one).
For the top tank, the discs are at the bottom of the tank and when they are activated the water passes through them. It’s not the classic 1.7 MHz discs that you see in many systems but which get very hot.
Ok found DIY fogponics towers as early as 2017, so, though certainly an interesting project it certainly isn’t earthshatteringly new or original
The thing that is keeping me from diving into *ponics is all of the plastic. I am looking at modular terracotta components which should be inert and have a very long life but finding the sweet spot between minimum mass and impact resistance is tricky. There are some methods such as grogged paper clay slip casting that may offer a route to tough, lightweight, low fired (within the range of a solar furnace), ceramic modules for *ponics applications but I don’t think they could ever compete on price with plastics outside of a DIY context and even then you’d need to still be working at a medium scale to minimise the distributed costs of setting up the production line and individual plaster moulds.
I totally agree with you. Like you I was thinking of ceramic modules or cork modules which has good properties too. But for DIY the PVC tube is still the cheapest and easiest solution
I’m really struggling to understand why this even had to be a piezoelectric fogponics system when energy consumption is the focus. A single mister at the top could have accomplished the goal. But you don’t even need a mist – you could just save a lot of effort and energy consumption by creating a drip system by pouring the pumped water over a dispersion screen, and setting it up on a mechanical timer to turn on/off every 15 minutes. The water falling back into the reservoir adds a ton of oxygen back into the water, so that shouldn’t be a concern either. There are hydroponics towers on thingiverse that accomplish just this. Hope this helps!
Cool project.
You might be able to use a simple led and a LDR to measure fog density and know when it needs cleaning. Once the light values increase the fog is less thus you could calculate the point I suppose ;)
Thank you very much!
In the root chamber there should be no light for the roots and to avoid the creation of algae. I think that LED is not the solution. I’m thinking of a humidity sensor or measuring the current before the disc as mentioned above
Now I yearn for a return to Epcot. That visit sparked my first intro & interest in Aeroponics and hydroponics. Back in the day as a teen when 150 watt hid in ballast lights were just affordable, and you could still buy hydro and aeroponic kits. If you like growing go to Epcot @ Disney world and see it