How many plants do you plan on growing in this media-less system?
I’ve tried it in my early hydro years and didn’t like it.
I am thinking of 16 in a 4 x 4.
There is an australian guy on another forum who does it.
Seems to work fine.
The inefficient thing that you mention is true. But water is not that expensive where I live. Nutes are not cheap, but ok. If that was the only problem, I can deal with it.
What I am worried more about, is that you need a big rez. And at a certain time you can not use the water in the rez anymore. Because then there is just not enough water in the rez to fill the tray to the level you like.
And then the water in the tray will not reach the overflow. Thus having the risk that your pump runs dry.
It’s very big with some members on open grow
I’ve never tried it but a friend ( Hammie hydro ) is big into it I believe you just need an old car seat for the material and it’s washable for reuse
I’ve seen the results and it looks interesting
Paps
That is was I was meaning to say but was to lazy to write it all down.
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On the other hand: The larger your rez, the longer the proportions of the different elements remain in good proportion with each other. Your nutes stay stable longer.
Every system has its up sides and down sides.
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Sorry to take so long in replying!
You make some good points - in fact, I agree that an air pump isnt needed on E/F setups. That was 100% my bad.
However, I would argue that the miniscus layer that forms on the roots when the water is drained out is at least as important/effective in increasing the DO as the fluming/agitating action of the pump. Both expose fresh surface layer of water to the air. In the rez, you are limited to the total surface area of the rez, but on the table, you have the total surface area of each piece of medium you are using plus the wet surface area of each root strand. Even a powerful pump will take some time to bring a rez to 100% DO, but those super thin layers on the roots and hydroton reach 100% DO much faster.
This fast replacement of the depleted O2 allows the roots to continue to absorb plenty of O2 even as they use it up. Roots can use up O2 faster than thick layers of water can replace it.
Thats why I argue for shorter flood times, but you are correct that an air stone is redundant. 
True. When I say “meniscus layer” I am referring to the same shape the water forms when most of it drains off of an individual root hair. If you look closely at a wet roots laying on a surface - like a piece of hydroton or the bottom of a bucket, etc, you can see that same curved shape to the very thin layer of water as it bridges between the surface and the root and between other root hairs. That layer of water extends to cover the root and the media surface. The curved meniscus itself is actually the thickest part of the “layer”.
Its that super thin layer of water that is the key to maximizing oxygenation of the roots - without drying them out. Thicker layers of water slow that oxygenation down. No water layer at all of course is bad, so you need to replenish it just barely faster than it dries out or gets absorbed by the roots.
One benefit to having media like hydroton is that each piece of hydroton holds some water after it drains out. This water wicks out to the roots as they drink, keeping them supplied with fresh, super oxygenated water longer than just plane roots with no medium.
I got most of this theory from the guy who invented the Membrane Meniscus technique. Lots of good reading in this PDF. The only real problem with his technique is the membrane. Root seem to be better than any membranes I, and others have tested when it comes to growing our plants.
Darn. The file is too big to up-load here. You can Google Membrane Meniscus Technique or PM me and I will send you a link to my Google drive so you can download it.
Let see if I can upload his patent files…
miniscus.pdf (1.1 MB)
Here is a quote from that PDF:
A further important feature of the Membrane-Meniscus Method is that nutrient is supplied to the roots exclusively by a meniscus “film” rather than a significant depth of “liquid”. The meniscus film provides the essential moisture that roots need, and permits rapid diffusion of oxygen from the surrounding air to the roots.
When I tried it, it seemed to work really well, but the roots out smarted my membrane and got down into the water into what he calls the Nutrient Supply zone. The membrane is supposed to allow water to wick up through to the roots, but keep roots from growing back down to the water. Thats a tough thing to manage.
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I do totally agree with everything you wrote.
I read a scientific article that showed that the higher the frequency of feeding, the higher the yield.
It is absolutely true that dry roots can hardly absorb oxygen. Only wet roots can do this. And indeed if there is a very thin layer of water around the roots, and around it oxygen in a gaseous state, then you have the optimal conditions.
I hope to start with an experiment in the near future in which I want to grow without any medium. So plug cuttings in neoprene pucks and then when they get roots, I don’t want to put these roots in clay pebbles or something like that. The roots simply hang loose in an E&F tray. The tray is closed with a lid and holes for the pucks.
I want to flood every hour (with lights on). In principle just until the highest level of the water is reached, and then ebb again. Let’s say this will take 15 minutes. I think (but I’m not sure yet) that in the 45 minutes for example that the water is gone, the roots will still remain sufficiently moist and retain the layer of water you mentioned.
I don’t want clay pebbles, because I would love to work without a medium at all. Did too much cleaning and transporting of mediums in my life
I really appreciate your contributions because they make me think. And they reaffirm my findings so far.
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That set up sounds like it’s blurring the lines between E&F and Kratky DWC.
Go for it, and document everything! We’ll never learn anything new if nobody tries anything new.
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No, it is traditional E&F.
The only thing missing in my experiment will be that there is no small netpot filled with pebbles or something else.
In Kratky most people also have a netpot with clay pebbles to give the plant more to hold on.
It is not something I invented by the way. There are already growers who do it. But for me it will be new. It works, I know that. Just want to see how long the roots stay wet, and if it does not affect other factors (like yield, hahaha)
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You’ll need netting or stakes.
I doubt that. The root mass will get huge fast and the roots will all get tangled up. Plenty of support.
I grew this root ball - from a single C99 plant - in just a 3" net pot. The root chamber is 24" in diameter and 55 gallons total. No support other than that 3" net pot. I did do a scrog screen for the plant, but I did it the way you are supposed to do it - trained the plant to grow UNDER the screen all through veg and into flower until the screen was almost full.
All of my grows are ‘medialess’ and I have never needed any support to keep the plants upright.
Here is what the net pot looks like several weeks into the grow.
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Wow, just wow!
Did you start your clone (I guess you started from clone…) in a neoprene puck?
Then put the puck in a 3 inch netpot and then used a cloner first?
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No. I start my seeds in a mini hempy bucket filled with perlite - which is just a dixie cup with small holes cut near the bottom of the cup. I start my seeds by soaking, then do the paper towel trick or sometimes I forget them and they put out long tails while still in the water. Then they go into the dixie cups for about a week or until they get to be about 2"-3" tall. Then they go straight into the foam pucks and into the air atomized (AA) aeroponic system. It usually takes them 2 to 3 days to get over the transplant shock and start growing fuzzy hairs.
This baby is recovering from some major stress - I used waaaay too much pool shock and almost killed it, but its been 4 days and its pretty much recovered.
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