Aeroponic System Categorization (flex/vertical/horizontal trays)


#1

I have done prototyping on hydroponic (DWC) and aquaponic methods. Recently, I ran into OpenAg at St. Louis University, and am so excited to work with the community!

Here in STL we are looking to do prototyping on Aeroponic systems. We are interested in documenting the variety of aeroponic systems to date. Our goal in this post is to begin to categorize all of the different aeroponic systems available. In addition to categorizing we want data on how well each type of system works. This will allows us all to better document all of our findings, and provide future aeroponic farmers with a resource to choose the system that meets their need. It will also make collaborative research a lot easier. As of now we have found three categories. 1) vertical systems 2) horizontal trays and 3) flex systems. As I am a new user I can only put 2 links so we need your alls help.

Please upload any known links, and feel free to add categories that you all know of.

Vertical:

  1. https://www.farmtek.com/farm/supplies/prod1;ft_hydroponic_supplies;pg113700.html

Flex:

  1. http://www.biocontrols.com/secure/shop/item.aspx?itemid=132

Horizontal Trays:

Thanks to all of you!


Aeroponic design guideline roundup
#2

I think it depends on what you’re trying to grow and the environment that you’re trying to grow in as to what type of aero system you would use. Small plants seem better suited for vertical growing and larger plants would probably make more sense being horizontal. Lighting system can be adapted for either system however if you want to use good old fashioned sunlight then that would need to be a consideration also. So I think it’s more of a question of what makes sense for what you’re trying to grow. That being said I do believe aeroponics is the best method for growing most plants when it comes to control, productivity and the ability to replicate a successful grow.


#3

We often here citation of aeroponics being 70 percent more effective than hydro. Have you found that to be the case?


#4

I have only grown using aeroponics so I can’t make a comparison to any other method of growing. I have a few reasons why I’m a big fan.

  • There’s less water in the system…water is heavy
  • Less RO water needs to be processed each week for a nutrient change
  • You need less nutrients
  • Nutrient flow rate is very low < gal/hour
  • The water is never exposed to the light unlike many hydro systems… no algae issues
  • You can see the health of the roots
  • You can manipulate the roots in aero
  • You can adjust the nutrients/PH very quickly
  • The only media you will waste is a rock wool cube/rapid rooter

#5

I`ve run NFT and high pressure aero side by side. All i can say is its a good thing aero takes no looking after because the NFT was a fulltime job.
An aeroponic root with an effective diameter of 1/4" may take the plant 48 hours to produce using minimal resources. A hydroponic root with an equivalent surface area will take considerably longer to produce and consume more resources that could be better used elsewhere. Hydroponic roots are solid like a rod or bar where aeroponic roots are more like a pipecleaner or bottle brush.

To add to Adams list, Aeroponic root chambers can be made of lighter and not necessarily water tight materials (lower cost) Minimal water and nutrient requirement allows you to run drain to waste. Drain to waste ensures the elemental content of the nutrient is constant and it prevents debris, heat and potential pathogens contaminating the reservoir. (nothing comes back). Clean nutrients reduce/negate filtration requirements and nozzles are far less prone to clog. Theres no need for daily PH, EC checks and adjustments, topping up or guessing when its time to renew an elementally unbalanced reservoir. You simply replace it when its gone.

My outdoor chambers are 5m long x 0.6m wide x 0.5m deep (1500L),they get no more than 20L a day. I have a 26 gallon AA aero system with 6 tomato plants thats currently on a meager 285ml a day.


Aeroponic design guideline roundup
#6

I have only dabbled in aeroponics. The oft referenced and most likely extensive NASA findings that aero is the best, was good enough for me.
Vertical farming (with horizontal trays) dominates commercial installations due to its structural scalability.

As an addition to Adam’s and Atom’s list,

  • The aeroponics mist encourages development of a root structure suitable for transplant into soil without the transplant shock associated with hydroponics.

It’s important to me as I’m interested in rapid seed growth and hybrid farming, instead of exclusively indoor.


#7

@derekschulze I did find this study which appears to have some concrete numbers about increased yields due to aeroponics

“An average increase of about 19%, 8%, 65%, 21%, 53%, 35%, 7%, and 50% in the yield was recorded for basil, chard, red kale, parsley, bell pepper, cherry tomatoes, cucumber, and squash, respectively, when grown in aeroponic systems, compared to that grown in the soil.”

Edit:
Thank’s to @Atom for pointing out that this is for Tower Gardens which use low pressure aeroponics which is not the same as high pressure aeroponics. If anyone can find studies on HPA I’d love to see them but I have yet to find good data on this.


#8

That study relates to a tower garden which isnt aeroponic as liquid water simply flows or drips from the top down. Imho, its vertical NFT / Drip hybrid masquerading as aeroponic. The numbers are representative of hydroponic to soil.


#9

There are 2 types of aeroponics, high pressure and air atomised. These are the only ones that can fulfil the droplet range requirement and provide the necessary level of control…Having said thet, they can also produce hydroponic results if too much mist is used. An aeroponic system should be designed to deliver the absolute minimum amount of mist with tight control, You can easily increase the amount of mist but its impossible to reduce it below the design minimum if you have too much :wink:
Ideally, the misting system should deliver no more than 1ml of liquid per 100L of root chamber volume, The mist should consist of 5-80 micron droplets and be directed into open space to prevent localised root wetting and uneven mist coverage. Very few folks would contemplate building a system to those specifications so its no surprise that data is a lttle thin on the ground :wink:


Aeroponic design guideline roundup
Syringe Pumps - Peristaltic Dosing Substitute & DIY Aeroponics
#10

I found that Indoor Harvest offers a High Pressure Aeroponic rack system now. Interestingly enough while looking through their site I read here that they were the ones who helped design the High Pressure System for the V1 Food Server that used to be housed in the Media Lab. Here is a link to pictures of that system they designed and built for MIT. It looks to be extremely similar to the product they’re now selling:


Aeroponic design guideline roundup
#11

An aeroponic root bundle 15" in length should be 9"-12" across . If i saw these roots in my chambers i`d be worried :wink:

https://drive.google.com/open?id=0Bxo_YC67jiAESVB5S3d5aUhWTU0


#12

I will say, that was when we were deconstructing the unit. They had been running an experiment with Basil and had turned off the system for 3-4 days prior so they were pretty well dried out already.

That being said, what do you think the average 35 day lettuce (or comparable leafy green) root bundle will look like if grown in one of your chambers in terms of size. I know you’ve mentioned that 15" is the minimum depth for a reservoir. Are you saying that for the MVP we should plan on 9-12" of root mass per plant? To me, this seems like it would crowd the plants then if they are placed 5x5 or 6x6 which is more optimal for the light distribution.


#13

The roots will dry out but its pretty clear those vertical roots didnt have a lot of girth to begin with. When the roots dry out they change colour and become brittle but they dont shrink by that much :wink: Corriander/cilantro can generate a 12" root bundle 6" diameter in hpa. I grow lettuce in the towers as its more efficient, the roots take up all the drop to the site below which is around 9" and widthwise they fill in the open space on the inner wall of the tower which equates to 7" per plant but its not the same inverted cone shape you get with a flat chamber due to the vertical aspect, its more of an elipse, wider than it is deep. You may get away with a slightly shallower chamber for lettuce but a lot will depend on the nozzle type (mist pattern,cone diamter and throw distance) and placement. If you use netpots they will also reduce the available height.in the chamber The important thing is to ensure the mist coverage isnt restricted, upward firing nozzles in a low height chamber will tend to impact directly on the underside of the lid and droplets dont bounce :wink:
I`d recommend experimenting with different chamber heights and nozzles but you really need to get some experience first so you know what the goals are. Aeroponics isnt like any other method where you just sit and watch (and hope). You have control over the plant and the ability to steer the growth. Think of hydro as a car with automatic transmission and aero as one with a manual transmission, Applying the auto thinking to the manual gets you redlined in 1st gear and not getting anywhere fast ;).

Practical experience is the way to go, Keep the roots too wet and you`ll notice they will head straight for the floor and pile up… If you keep them too dry (or the droplet size is too small) they will spread horizontally at the top of the chamber and form a canopy. This usually results in the roots under the canopy blocking mist to the top of the canopy. The goal is to create an inverted cone of roots that gains in both girth and length. .
If you compare the earlier root pic to this one you can see theres quite a difference.


Aeroponic design guideline roundup
#14

If you’re growing in space then aeroponics make total sense given that the water droplets and roots can just float around. The extra hang time of the water droplets will give it a much better chance of hitting the plant roots. For us earth folks we have to deal with thing that’s always dragging us down (gravity). When/if the roots get big enough they’re going to end up going down because there’s nothing to support them. I think that some type of trellis in the misting chamber will give the mass of the roots something to hold onto. The obvious benefit of the support is that it allows the mist to circle around the roots much better. Basically you get half of the “space affect” which is helping the roots to “float”.

I agree with @Atom that an inverted cone shape for the roots makes the most sense when each root gets a single misting nozzle. I think larger roots would benefit from multiple nozzles which would give more flexibility to the shape of the root trellis. Misting nozzles supposedly get clogged up too, so having some type of redundancy built into the design makes sense. After three successful grows I have yet to have a clogged nozzle (and I recirculate).

The biggest weakness in aeroponics are all the points of possible failure for the misting system.

  • clogged nozzles
  • pump failure
  • plumbing failure (dealing with at least 80psi +)
  • timer failure (could be a simple timer or in my case a linux based micro-controller)

If your misting system goes down you don’t want your roots to start drying up and with no medium it will happen much faster.


#15

First of all, I want to say that these are hands down the best looking roots I have ever seen @Atom.

I completely understand the value of practical experience, quite frankly, I wish I had the resources to build a dozen aeroponic prototypes but I do not have the money or time required at this moment. I completely agree with you about there being an immense amount of control that comes with this style of growing. I appreciate your advice on the distance, I had been planning to use net pots but honestly, if I can avoid it I’m going to. I’m going to make a post on the MVP thread about my plans, I’d appreciate your feedback at that time. I’m curious if you have advice for sourcing parts especially the misters themselves, I had been looking here at BETE. Also, what do you use for piping/tubing (why)?

To me the best part of all of these weaknesses is that they are definitely solvable. While I agree for a DIY project it can get tedious and difficult to make sure everything works correctly I think a manufactured product could definitely function reliably. There are solutions and fail-safes that I believe can be put in place. For example check out this clever usage of a microphone as an alarm for HPA system failure.

Which brings me to my final question: What is the reason that plants grow more efficiently with HPA? I’ve heard that due to the smaller droplets the roots “don’t have to work as hard” and claims that less nutrient even is required for the same final outcome. Does anyone have articles/proof of this? I am trying to better understand the requirements of aeroponics so that as I make sacrifices and cut corners for the MVP I do not compromise the function. For example: is an accumulator/pressure tank absolute necessary? Could I run a simple actuation 5 seconds on for every 5 minutes with an inline 100 PSI pump? Does that initial blast with larger micron droplets due to lower PSI completely negate the added value of HPA, or is it just not ideal?


#16

Hi Adam
gravity doesnt have too great an effect on 5-80 micron droplets, a second of mist comprising less than 1ml of liquid will fill a 26 gallon chamber with droplets that will remain suspended for well over 5 minutes. The roots in the pic were grown here on eearth not in space :wink: Aeroponics defies a lot of conventional thinking, folks assume roots only grow downwards due to gravity but in aeroponics they can grow upwards and sideways just as easily. If you monitor the roots it becomes clear that they can sense the origin of the mist, when the roots are kept too wet they tend to “follow the water” running down them and dripping off the ends which leads them straight to the floor.
Pump failure is less likely when an accumulator is employed… Aeroponic systems cycle hundreds or thousands of times a day so its best to use a timer fitted with a solid state relay that have no moving parts to wear out. An SSR will typically have a life expectancy of 30-50 million cycles.
There are many misconceptions about aeroponics, like plants die in minutes which isnt true. If you turn off the system and time how long it takes the plants to wilt you`ll be waiting for quite a while, The roots in the pic above would survive without mist for at least 5-6 hours, it would be less with less rootmass. Rootzone temperature is one of the biggest factors with aeroponics.


#17

Hi Peter,
The reason aeroponics is more efficient is because its has magical properties…at least thats what folks would heve you believe :wink: Its actually quite straightforward,the plant can grow aeroponic roots faster with less resources. The common claim that aeroponics needs much lower nutrient strength is also easy to understand. Consider a 10 gallon reservoir of nutrient at EC 1.0, if 5 gallons of water evaporates youll have 5 gallons with an EC of 2.0. Now consider a 50 micron droplet with an EC of 1.0, if it reduces to 25 microns before connecting with a root it will have an EC of 8.0 because its volume has reduced by a factor of 8. If it reduces to 12.5 microns itll have an EC of 64
I dont recirculate nutrient in aeroponics because its not worth reusing…


#18

While this makes sense from a mathematical point of view, my only question is this:

Does this mean that my EC needs to be based the size of my droplets?

In the example you gave, wouldn’t an EC of 64 be far too high for a plant? What EC do you keep your reservoirs at, and what is your goal EC for the droplet when it connects with the root (lettuce as an example). As always, I appreciate your expertise in advance.


#19

I always run 1/4 to 1/2 normal strength and fine tune based on the difference between the inlet and outlet ppm. For lettuce typically 100-250ppm (EC 0.2- 0.5) depending on the size. The outdoor toms (gardeners delight, indeterminate) have 5-6 trusses on them so far and theyre currently on 600 ppm (EC 1.2). If you run high strength nutes and minimal water youll soon run into issues because there isnt much run off to take away the excess. When you run hpa youll discover plants want a lot less water than you thought possible..When you get the system up and running itll all fall into place unless you overdo the mist :wink:


Aeroponic design guideline roundup
#20

Hi Atom,

Thanks for sharing your considerable insights on here. I’ve found most of it lines up with my own experimental AA aeroponics system. I just read your May post about 1ml of liquid per 100L of root chamber volume, which is really interesting but where does that come from? Is that anecdotal or based on something else?

For your reference my grow chamber is in a 55 gal drum so according to that it looks like 208ml would suffice. Is that per cycle or over some timeframe? I mentioned in another post but I end up with probably 250 to 300ml per cycle which is currently with about 12 seconds every 5 minutes.

I arrived at that setting basically anecdotally from observing results: based on plants not looking wilted and the rockwool cubes not being too wet. As the roots get bigger, root size and color are most helpful as the rockwool seems to get drier with the roots blocking the mist.

My mist configuration has evolved to a central mist wand with 5 mist heads arranged in 3 rings at three heights to maximize coverage of the inside chamber walls. Currently using antidrip mist heads from 0.12, 0.16 and 0.20 inch orifice size which get 65-75 degrees coverage.