Experimenting with fogponics, could you help?


@Atom have you ever tried using nozzles from a Pressure Washer? Also, how do you measure what your microns are? I’m testing my system but having a hard time knowing if I’m actually getting what I want. I understand this will be shown with roots, but I haven’t gotten quite that far yet. I also want to know for future reference with testing how you’ve done this previously.

@Juan1 I’m curious, how are the cherry tomatoes doing? I’m still super confused as to whether or not this works. If it does, why are other people going through such trouble to create mist when it could be done using an atomizer?


Pressure washer pumps have been used for aero but i havent used one. As a standalone pump they dont offer much in the way of control, they usually have a lot of brass parts (not good with acidic nutes) are noisy and consume a fair bit of power. As for micron sizes, it depends on the nozzle but typically the more expensive it is, the more information will be available. For example, you cant expect as much with a $1 mass produced plastic nozzle as a $200 air atomising nozzle. Testing nozzles is an expensive business, big firms like Bete, Spraying Systems etc have their own test equipment, labs and technicians. Here`s an idea of how they are tested (nozzle test at 8:16)

Here is some droplet data for the nozzle in the earlier mist plume pic

Having the data is good but, at the end of the day, the most expensive nozzle can deliver the same results as the cheapest nozzle and vice versa as a lot depends on the user. You can expect a few failures initially but as you gain experience you`ll find its very easy to get results. Its similar to riding a bike, seems impossible until you get the hang of it :wink:


Hey @Webb.Peter here are some picture as of today.

This is the Fogponic plant

This is the Kratky

What do you guys think? Both plants look really healthy, in fact the fogponic one is a bit taller.


The ultrasonic fog roots look good but have the typical whispy quality associated with the small droplets. The kratky roots are more uniform and appear a little whiter but that could be the light. The kratky will have the advantage over fog/aero when both root masses are small but as the rootmasses increase you should see the fog/aero pull ahead and leave the kratky in its wake. I would be tempted to switch the plants over for a few weeks and see if the kratky roots transition to fog without developing the telltale whispy quality.


Yeah thats a good point, I may change them and see if the kratky becomes whispy. So far I have not change the water but I tested the concentration and both samples were over 1200 ppm. They are just flowering too, I think the flowering period is a little late. Any recommendations on what to do Atom?


Is this what the water started at and you haven’t changed either?

What is the water level difference between the two grows? Is one clearly drinking more water?

Also, have the fogponic roots reached the water yet? If so do you think that sort of changes the experiment?

BTW: The flowering is probably due to a lack of light, it looks like they’re just in a window? Tomatoes need lots to produce good fruit.


Its the original water yeah,

So far the kratky has used about twice as much water as the fogponic system. Yes, the fogponic roots already reached the water, I am going to change it into an external fogger soon, am just waiting for the fan power convertor to arrive.


1200 ppm is pretty strong for aero, depending on the meter conversion its EC 1.7 (0.7) or EC 2.4 (0.5)… My hpa outdoor toms are happy with an EC of 1.25 and they`re 8ft tall…


Now the real work begins. I went to the handle and squeezed the trigger. Pathetic. Despite the roar of the engine behind me, this “monster” had no bite! I shut her down and looked around. Time for some “existing pressure washerify” commissioning!

If you don’t really know your way around a new piece of equipment, you might find yourself looking under the hood to no avail. This was the situation I found myself in, but if you’re used to tinkering around with equipment, after a while you may figure it out. As I inspected the pressure washer, I concluded that since there isn’t much to this thing, if anything is going wrong it’s in the water supply, the pump, or the handle/wand/nozzle assembly.


Started with a fogponics system but plant growth was limited. I added misting capability and plant growth took off. For a while I ran both together: originally with misting as a back up for fogging and then later the converse. Unfortunately, the ultrasonic fogger heads went bad after about a year so I ended up removing that part of the build altogether.

All told, the extra effort to deal with the floating fogger, fine-tuning the nute reservoir (temperature and nute mix), ducting the fog in and configuring a waterproof blower fan ended up adding little or nothing to plant success relative to the misters. There is definitely a sweet spot as far as the temperature goes and fog mobility. For me the juice was not worth the squeeze.

The system is managed with an Arduino Yun and controlling the fogponics was straightforward but I tried many sensors and none could consistently indicate when fog was present.


Thanks for your comments. It’s rare to find people with experience in fogponics, let alone fogponics and HPA.

Could you define what you mean by “plant growth was limited” what were you growing? Was the plant nutrient deficient, bad roots, or just growing slow?

It sounds like you got pretty far along with your design of a fog distribution system. Have you seen this patent? It mentions a sensor for detecting fog as well.

I’d be very interested to learn more about your system, especially what you’ve settled on now with the misters. I just completed a HPA system for the MVP.

Aeroponic design guideline roundup

Your welcome and thanks for the links…will check that out.

Plant growth was limited meaning really slow and this was across several varieties including Swiss Chard, Kale, Bo Choi and Basil.

A little more on the system (which you can somewhat see inside the grow chamber in my avatar)…basically a 55 gal drum connected via 1.5" insulated hose to a 5-head US fogger that ran in the nute reservoir. A fan blew air into nute reservoir and pushed fog out into the grow chamber. I tested many different on/off times.

Another difficulty that I recall now with the fogger was that it really heated up the nutes reservoir by 5-10F; not a problem in the winter but in the summer was annoying. The floater for the fogger awlays seemed to be in the way in the way in what was a 17-gal plastic cooler (prob 7 inches diameter in a 12 x 18 space).

When I added the misting rig growth took off…technically not sure if it is technically HPA but maybe Mid-Pressure as I do not use an acculator/solenoid but am getting about 120 PSI from Aquatec 8800 pump.I have a flow monitor that measures misting volume which for the record is:

  • on for 12 seconds every 5 min
  • getting about 280-300 ml per mist
  • recommend antidrip heads (no filter) from 0.12, 0.16 and 0.20 inch orifices being tested



I would love to get a definitive answer to why growth is limited - but that seems to be the general consensus with fogponics @Juan1 correct me if I’m out of line here.

@wsnook This is definitely of value to add to your post. Both in terms of the conversation about fogponics and @seiche’s most recent post regarding his HPA recommendations. This is a form of the most basic HPA system - without a solenoid/accumulator.

@seiche Thank you very much for your detailed reply. I would love to hear more about your experience and hear your contributions in response to the compiled documentation regarding HPA we’re trying to gather: Aeroponic design guideline roundup


Im running the same test as you, however I have a problem with fog escaping the reservoir and the root chamber. How did you solve that problem?


@Webb.Peter I added a link and brief summary of this thread to the reference designs section of the aeroponic roundup post.


I am no expert, Peter but I do not think the growth is limited. Fogponics do not limit the growth, in fact, its supposed to speed it up because of the droplet size. @seiche could you post some pictures of the roots? If the system is working properly you should see very hairy, almost fluffy, roots. Do your roots touch water at all or only mist? I ask this because in my experiment I could not properly measure fogponic effects because there was water at the bottom of the reservoir. The roots grew long enough to feed on the water instead of from the mist.


thanks @Webb.Peter for directing me to this thread. skimmed it a little. Need to come back and read in more detail.

I’m experimenting a little with piezo ultrasonic disc mist makers. Right now just have a simple tub that have 3" netpots, rockwool, and clay beads. I have two pepper seedlings growing great and a few other experimental crop seeds starting to germinate.

From what I’ve read, these systems are better at starting seeds than maintaining them to full maturity. I’d like to fix that if possible.

Right now i just have a shallow bucket with the piezo discs on the bottom (not in a float). there is a space for air/fog with plenty of water under that if the roots grow that far.

The main problem is that these piezos make a lot of heat and therefore will heat up the roots. Since plants grow best with cooler roots i’m thinking that even a simple arduino controlled circuit could help. Basically have a temperature probe in the water. When a certain temperature is reached then, they go off. Perhaps at the same time a fan could turn on and circulate air through the fog chamber.

Currently i just have them turned off with the lights at night.


Okay, so I’ve been doing some more reading about studies on plants and the temps they like. I’m still trying to contemplate it all. Found lots of good stuff. Some on plants in dirt and some in hydroponic. Couldn’t find much about the differential temperature between roots and leaves though some sources talked about osmosis and capilary action. Some even mentioned some plants absorb water from the air.

But either way it sounds as if a temperature difference is needed for plants to absorb water and grow. I am assuming that this means plants will not grow or grow very slowly if their roots and leaves are at the same temperature. If this is true then in a fog or aero or hydro system it seems critical to keep roots cooler. Though i wonder if warmer would also work if supplimented with more oxygen (CO2?)?

The downside is it is kinda difficult to keep roots cooler in an artificial system though not impossible. I saw some threads on here about root cooling systems.

I’m mostly talking to myself right now.

But a correlation in water systems is that the warmer the temps get the lower the dissolved oxygen gets. In still not certain whether it is actually dissolved CO2 that roots need since plants breath CO2 and exhale oxygen. Most of these articles talk about plants and dissolved oxygen. I kinda suspect they were written wrong. Maybe it’s just easier to test for dissolved oxygen than dissolved CO2. Or maybe my assumption is way off base. But regardless i figure if you have a simple air pump and air stone (then you are sending in both CO2 and oxygen, etc.).

So anyway, it seems that if one is trying to control a simple system like a piezo mister like i was talking about before then it would be best to not only turn it off when the water reaches a certain temp but to also try turning on a cooling fan which should also help circulate air to the roots which may be more important than the heat. I’m thinking the heat doesn’t matter all that much, what matters is if the roots are suffocating and whether there is a temperature differential between roots and leaves to achieve maximum growth potential. It is interesting that plants grow the most at night when it is cool.

I have designed a quick 40mm x 40mm fan adapter for a 5v fan i have lying around that i can hook up to my arduino for just this purpose. I designed the fan adapter in a 3" netpot size so it will fit a 3" hole just like the plants without fussy hole drilling or modding or whatever. I can share the CAD / STL file for anyone who wants to 3d print their own.

I do have an airpump with air stones that i could use too, but i kinda just wanna see how the simple temp probe and fan system works first.

So that’s all my random babbling for now.



You do not need to have the piezo always on. You can use a timer to turn the piezo at intervals (pulsing). A good interval for a 5 gal bucket is 15 sec on 2 minutes off.

You can check how these do it. They explain it pretty well.

If you put the system in enough water the piezo will not heat enough to affect the root chamber temperature. This way you do not need a water chiller. If you have the piezo in the same chamber as the roots (ex not using an external fogponic system) I would not recommend using a fan. I tried using an external fogponic system, unfortunately, my plants died, it could be the container was not properly sealed, the fan was too powerful, or the fogponic system did not work and the roots were feeding on the water at the bottom of the reservoir. Roots do not react very well to air flow either.

I recommend you try pulsing the piezo before you go all fancy and work up from there. You also need to take into account nutrients. Are the nutrients getting into the fog? I did a small experiment where I condensed fog and measured its ppm and compared it to the liquid solution, the results were positive, but I did not test if the fog loses nutrients over time. Maybe the more nutrient dense fog is also denser and tends to stay at the bottom, eventually suffocating the plants?

@Webb.Peter posted a patent about an external fogponic system that recirculated air to have homogeneus temperature and nutrient concentration through your fog. I am not sure if he posted it earlier in this post or in some other post.


Thanks for the reply. I also had the idea of pulsing the piezo element, good idea. I may implement that. No reason i couldn’t implement all three together. I still like the idea of having a redundant temperature shutoff even if pulsing the ultrasonics.

The tub I’m currently experimenting with is small. Smaller than a 5 gallon bucket, though i do like the 5 gal systems. Right now I’m experimenting. It could fail but that’s ok. If it’s successful i can always scale up. Personally i like the idea of the roots reaching the water and although that may defeat the fast growing of the aeropinics systems it sort of makes it a hybrid hydro system. There is some guy on YouTube that grows lettuce in plain buckets of nutrient water. No misting involved. Seems to work okay for him.

The fan im using is tiny. It is only 5vdc. The air flow is not much. It won’t be on very often anyway. Only when the ultrasonics are off and even then maybe only for a min. I’ve got the adaptor printed and the fan mounted. I like to do my own thing.

That’s cool you’ve experimented with the external mister idea. Good for you. That might be a good idea with a large system but in small bucket based systems i don’t like it. That’s not something im going to try as that seems way too complex and over thinking the problem to me. Im not interested in ppm values for nutrients or how much are making it into the fog/mist at this point in time. One step at a time.