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electricsun

Not really aeroponics at all?

electricsun
13 years ago

I've been information mining the net on aeroponic setups for the better part of a week or more and think I have a pretty firm foundation on the technique.

What confuses me is the depth of the assorted trays, tubes, gulleys etc utilized in essentially every system I've seen, both turnkey and diy. They're all extremely shallow, which In turn seems to me to mean that the root structure would be laying on the bottom of these very short in depth chambers with half those roots facing plastic, and not air. In this way all the aeroponic systems I see have more in common with NFT and DWC than pure aero.

With the roots sitting on the bottom some 59% of the roots surface area is not exposed to air or nutrient spray (aside from runoff)

Which brings me to a question, if what I observe is correct wouldn't long vertical tubes, say 6" in diameter and 3' in lenght make a better chamber as the roots could genuinely hang vertically, unobstructed in the air without making contact with the sides or bottom?

Thoughts welcome!

Thanks all

Comments (25)

  • zathras
    13 years ago

    Yes, you are quite correct. In fact, the majority of "aeroponic" systems you see around the web, aren't. Even the systems that have the roots hanging in air mostly use cheap, low pressure spray heads and not misters or foggers. The net result is that the roots are being soaked with streams of water and develop as if they were laying on the bottom of the container full of solution.

  • lucas_formulas
    13 years ago

    From my understanding, the inflationary use of the term "aeroponics" is just another example of colloquial abuse, either in hydroponics or in related topics or even generally speaking. It's kind of a trend of our age, to give nice sounding names to even trivial things, isn't it?

    Formerly terms were created to describe an existing thing best, - nowadays the meaning is individually home-spun around the terms eventually LOL. So far about the philosophical and the etymological part of the story... ;-)

    From my more practical understanding, aeroponics is only aeroponics when AIR is technically involved. Well, you could say that air is always somehow involved in hydroponics, but what I mean here is in fact air pressure or mechanical aeration. For instance, any mechanical low water pressure sprinkling isn't actually needing or using air, is it? So technically speaking, all systems that do not actually use air wouldn't be actual aeropocics per definition.

    Then again when designing or copying a so called real aeroponic system, using fine nozzles, spray and "AIR", you may still end up with some sort of a hybrid system. Which doesn't mean it doesn't deserve to be called "aeroponics", though. Although it uses real areoponic technology, it's hybrid nature may simply be due to a comprise with expense, space and effort that have to be considered to make any system economically reasonable.

    Picking up the idea of (individual) long vertical tubes (introduced by 'electricsun' ;-), - such concept and way of construction would indeed avoid ending up with some "hybrid", but would that be economically reasonable? Or would the effort and cost justify the difference (if there is any) in growth, quality or health of the crops?

    After all there is nothing wrong with any "hybrid effect", as long as some part of the root zone and mass profits from "aeroponics" and optimised uptake. Actually, when conducting experiments with "real" aeroponics, researchers found that if plants only having left a single root strain that would be sprayed with an 'aeroponic mist' , it would be sufficient for plants to ensure nutrient uptake!

    And, look at a standard NFT system, which actually refers to a nutrient FILM in some run, channel or gully. In reality the film only is a film in the beginning of the culture cycle, as with increasing root expansion it quickly becomes more like a flow. Soon after (with continuously increasing root volume) the actual water level climbs even more, to finally end up in, what could in fact be described as shallow water culture. Not even mentioning some replacement "NFT-variants" that do not even deserve the name (as in film) in the first place ;-)

  • homehydro
    13 years ago

    Yes, I agree as well that the shallow tube designs are not truly a aeroponic system, but more a combination aeroponic/NFT type system. And the ones where the roots hang down into the reservoir are a combination aeroponic/water culture system.

    Yes the Large vertical tube will give you a much better aeroponic affect, so all the roots actually hang in air. Also, flat panels tilted inward (Like a "A" fram design works great also.

    (video) http://www.youtube.com/watch?v=m6o5LTl6GJw&feature=related
    (video) http://www.youtube.com/watch?v=Y4UWGtb4Fmw&feature=related

    (picture of vertical tube design, at Epcot Center in Florida)
    http://www.csmonitor.com/Environment/Bright-Green/2008/0718/video-hydroponic-gardening-at-disneys-epcot-center

  • hex2006
    13 years ago

    Even a 6" vertical tube would struggle. The roots head downwards but also spread horizontally as they reach out into the mist. If they don`t block a 6" diameter pipe, its not aero its soakaponics labelled as aeroponic so they can add another $100 to the price :)

  • lucas_formulas
    13 years ago

    Well, you could build a mechanism (robot) that moves the nozzle up- and downwards on the 'z-axis' inside the tube, worth a few Grand LOL.

  • homehydro
    13 years ago

    I would agree that a 6 inch wide tube would be a little small depending on what plants you had growing, and how they were spaced. Although I don't see a need for any expensive setup or equipment in order to spray both top and bottom parts of the tube, as well as the middle. I would take a 3/4 inch piece of PVC tubing the length of the large tube. Cap one end (bottom end), insert it directly in the center of the large vertical tubing. Insert misters up and down the 3/4 inch PVC tube. Then connect the pump to the other end (top end) of the 3/4 inch PVC. If you have sufficient pressure from the pump all the misters will spray evenly thought the large tube.

  • hex2006
    13 years ago

    The problem is coverage and amount of mist delivered per hit, if you have too many nozzles you`re back to soakaponics, too few and you don`t get enough coverage.
    A single nozzle can fill a 26gal (100L) chamber with mist in under a second, the same nozzle in a 6" tube won`t have the same coverage if roots are in the way.
    If you need four nozzles to gain the even coverage you`ll need to reduce the misting duration by a factor of four to deliver the same amount of mist otherwise you are right back to square one..soakaponics :)

  • homehydro
    13 years ago

    Well if you really want to be that technical, then there is nothing called aeroponocs or even hydroponics. No mater how you lay it out, drops will form and drip down on other roots in any system. so they are all soakaponics systems. What would be the difference? If it's wet, it's soaked. So they are ll called soakaponics no mater the type of system it's in. Any system wets the roots, and any system that the roots with are wet, "is a soakaponics system".

    How far do you take it? If a drop of water hits the roots that is not in the form of mist, does that disqualify the entire system as being a Aeroponic system. That has never been accomplished. so again, how far do you take it?

  • hex2006
    13 years ago

    I guess you`ve never come across real aeroponics,just the soakaponic variety.
    To put it into context, 0.5ml of liquid (1/10th teaspoon)will generate more than enough 50 micron mist for a 100L chamber. There isn`t enough moisture delivered per misting to cause any drips :)

  • homehydro
    13 years ago

    That sounds like a fogger. I do believe foggers work better in delivering moisture in a aeroponic system, although I have never seen them used commercially. Commercially, I have only seen high pressure misters used, and they do put out enough liquid to condense/drip.

  • hex2006
    13 years ago

    A fogger doesn`t deliver enough water as the droplet size is too small at 1-5 microns. Aeroponics uses a 30-80 micron droplet size which appears foglike to the human eye but contains more water than ultrasonic fog. Wetness is a relative term much like PAR radiation is to light.

    {{gwi:1011244}}

  • homehydro
    13 years ago

    I must admit those roots look real nice,
    But if you look closely at the top left of the picture, you can clearly see water droplets forming and getting ready to drip. And as I asked before, does one drop make it a soakeaponics? If not, then where do you draw the line 2, 3, 4, 500 drops. Also if water droplets form on the top of the container, there is undoubtedly many droplets forming in the middle of that nice root mass.

  • hex2006
    13 years ago

    The root mass is a dynamic structure, the top of the chamber is cold plastic, there is a world of difference between the two.
    If droplets are forming inside the root mass they would also be forming on the outside and as you can see that clearly isnt the case.
    The condensation issue is due to overdoing the misting and moisture laden air coming into contact with a cold surface and dropping to dewpoint. Both are easily remedied by insulating the top and if need reducing the misting duration and frequency.

    Its not quite perfect yet but that just means theres still room for improvement.

  • zathras
    13 years ago

    Maybe not perfect, but those roots are looking pretty impressive. There is a point where the water doesn't drip and clings just enough for absorption and you're very close or there! What are the dimensions of that root ball?

    Dare I ask what's on top of those roots?

  • homehydro
    13 years ago

    Thanks hex2006,

    I believe you have a point with the surface temps, But I'm not convinced that there is no moisture buildup in the middle of the roots (not condensation, but humidity). Also how do I know both inside and outside temps of the container are not the same, canceling out any possibility of condensation? Bottom line, even if it were condensation, there was no answer to my main question. Does one drop of moisture on the roots constitute "calling it soakaponics", if not, where do you draw the line.

    P.S. You could insulate the containers but don't tell "lucas" He doesn't believe in that where he's from.

  • homehydro
    13 years ago

    "If droplets are forming inside the root mass they would also be forming on the outside and as you can see that clearly isnt the case."

    Sorry I cant agree completely. Yes the root mass is a dynamic structure, that is completely the problem. The inside structure would likely hold much more moisture than the outside of it. But just because I cant make out any water drops on the roots from the picture does not mean that they are not there.

    It's hard enough to see a clear drop on a white background in person, it's practically imposable in a picture like that on the internet. Bottom line, can I assume if one water drop hits the roots is it a soakaponics system then?

  • hex2006
    13 years ago

    If its soakaponics i guess you`d only need is a pond pump and sprinkler to get the same results. Give it a go and see how you do :)

  • homehydro
    13 years ago

    So then you are saying that it does not mater if any water droplets form, or drip on the roots. As long as you use a high pressure pump and misters that put out a 30-80 micron droplet size, you would not consider it soakaponics? Even if water droplets form and/or drip on/in the roots.

    I don't doubt that the higher pressure, and droplet size do a much better job. Just wondering how to define the term "soakaponics."

  • hex2006
    13 years ago

    Imho, any method that doesnt deliver the correct range of droplet sizes in a quantity that prevents over saturation of the roots will give you soakaponic results. In reality its a question of the degree of oversaturation as perfection is hard/impossible to acheive.

    Look at it this way, a gallon of liquid converted into the correct droplet sizes will result in soakaponics as you`ll deliver far too much liquid involved in the misting duration.
    Pressure is not the be all and end all. In the case of a high pressure pump, the droplet size will vary as the pressure builds, delivering 30-80 microns droplets after an onslaught of 100-200 micron droplets is pointless. A pump will struggle to deliver 0.5ml(or less)liquid at 100psi from a standing start.

    In summary, without sufficient control of the droplet size "and" the amount of liquid delivered per misting it`ll alsmost certainly be soakaponic.

  • grizzman
    13 years ago

    I find the concept of aeroponics very enticing, but have yet to figure out how to build one cost efficiently.
    So until then, it looks like it'll be soakaponics for me. And I've had good results so I can't complain.

  • donkaa
    13 years ago

    Grizzman,

    What do you consider "cost efficiently". Overall the costs aren't that high, especially considering the cost of WaterJetFlo (i.e. AeroFlo) systems base around $400.

    Rough costs for main equipment with some eBay'ing.

    Pressure Pump -$90
    Pressure Tank -$50
    Solenoid Valve -$30
    30Gal Reservoir -$70
    Misters -$1.50/each
    MicroPLC -$110
    Tube Fittings -$40

    So ~$400 for the essentials, and that's using a PLC as the pump, solenoid, timer controller, but you could get away with a cheaper short interval timer.

  • hex2006
    13 years ago

    Hi Donka,
    $70 for the reservoir is expensive, you wouldn`t need anything like 30 gallons unless it was a huge setup. Don`t forget to include a pressure relief valve for safety sakes. In the event the pressure switch on the pump fails and the pump keeps on running, the relief valve will protect you.

  • grizzman
    13 years ago

    My tomato can was a $30 pump, a $30 can, a $25 timer and maybe $10 for misc plumbing and water pumps.
    My NFT was a $30 pump, a $5 trash can, $10 for pvc downspout, maybe $20 for misc plumbing and frame materials.
    So yeah, $400 for any one system is a lot.

  • donkaa
    13 years ago

    Hex2006,

    I use Poly Drums for all my reservoirs and stock tanks, and my system has ~24 emitters so I stuck with 30gal. Pressure relief valve is a good call, I actually use commercial pressure switches from Square D and Johnson and have the PLC programmed to so the pump only has power for long enough to precharge the tank when needed. However, better be safe than sorry, though I have a feeling Shurflo and similar diaphragm pumps would destroy themselves before the ever reached >100psi.

    BTW, Which misters do you use? I use the threaded Tefen units that have their own individual inlet screens, so far not clogged emitters, and the nice thing is you can just unscrew a bad one and pop another in. Best I have found so far and they don't need high pressures to produce a proper droplet size.

    Grizzman,

    Yeah I guess that setup is a bit over budget. However if you were doing a small scale system where you could use a 5g bucket for the res and a cheap interval timer, you could cut $145 from that sum. My example was more comparing the pre-built stuff out there that is not really even close to Aeroponics vs. building your own that is actually the real thing with much higher quality components for nearly the same price.

  • hex2006
    13 years ago

    Hi Donkaa,
    The misters are stainless steel made by bete.

    Hi Grizzman,
    I look at aeroponics as a hobby, its not all that expensive when you compare it to some other unusual hobbies like sport fishing, hot air ballooning, skydiving or whatever your bag may be :)
    I`ve nothing against other methods, i grow stuff in the garden using good old fashion soil in the ground, pots and tubs. I have some toms outsode using soakaponics (pond pump + 360 degree sprinklers) and the 150psi aeroponic setup.

    They are all equally interesting in their own way.

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