I've been agonising over the size of the trough, so any advice would be appreciated - I want it as small as possible really to lower filler costs. The three varieties I grow are Glacier, Stupice and Early Girl - they all grow large 7 feet or more if I let them.

I was reckoning on 20cm (8") depth of material, 3m (9feet) long, and 40cm (16") wide, as there'd be two rows of plants. This adds up to 0.24 cubic metres of material, e.g. Perlite or Hydroton pellets! That's around 60 US gallons I think, or exactly 1 US Hogshead acccording to my converter, interestingly ;)

That's 13 litres (27 US pints) per plant. Can I get away with less, and if so, how much less? Thanks for any advice anyway!

Mike

Fantastic! That is exactly the kind of thing I was wondering about - I use wire cages as you'll hopefully see below, so they do indeed support themselves. Small net pots would be very do-able with Hydroton, not too pricey. Thanks!

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Don't worry too much about the root space they need, they will do fine as long as you give them the right nutrients and watch temps and PH - even if it gets a bit narrow in there ;-)

Hi there lucas-formulas - thanks again for your earlier advice! With a 2-3" pot, most of the roots will be trailing outside, in the covered trough I guess: I use a flood and drain setup, and grizzman advised the bare root masses would be OK as long as they were flooded often enough. It's a tough one really, as it would cost a fair amount to fill that trough entirely with Hydroton or whatever. What do you think?

Would be cheaper, and easier to clean up at the end of the season too - we'll see I guess.

So at least with big plants, I'm not convinced the medium is that important for aeration, in which case as long as the plants are well supported and 'watered' often enough, it has no obvious value at all. I think ;)

What an amazing photo! Good grief, tomatoes really do like a good root system. I think that photo answers my question very well! The only thing that's niggling is using ebb and flow, most of the time my tom's roots will be I guess a big clump of some kind and not separated as much as they would be either using a medium or DWC perhaps - so those roots on the inside would not be exposed to air. Your photo - what proportion of those root systems were under the nutrient solution 24/7? I'm wondering whether oxygenated solution is all that's really needed, rather than direct air per se.

>>One other thing: as I said to lucas_formulas in an earlier thread, I'd found my experimental tomato plants produced very dense root balls in their perlite pots (1 large pot, 1 small) - I don't believe any significant amounts of air would be getting into the middle of those masses after nutrient ebb<<

1. Every system has it's advantages (and disadvantages as well). The ebb/flood system has actually the advantage that air/oxygen gets literally SUCKED IN through the medium during the ebb cycle! Of course the density matters somehow. The only disadvantage is actually the need of a huge amount of media. If I understood you right, - that is what preoccupies you in the first place.

>>- but the plants were perfectly happy, as were the roots. The nutrient solution was continually and thoroughly aerated.<<
2. You did VERY well with your last setup and culture (as one can see easily) - don't forget that, and always keep in mind that one shouldn't change a winning team. At least not until a SURELY better is available!

>>So at least with big plants, I'm not convinced the medium is that important for aeration, in which case as long as the plants are well supported and 'watered' often enough, it has no obvious value at all. I think ;)<<

3. The amount of media is important and has it's clear value, but depending on the kind of setup you use! If you run a NFT system, you have a continuous flow and hence the roots do not need much media. In a drip and recycle, or ebb/flow setup you NEED a certain amount of media to keep moisture and also to allow roots to expand properly!

Last but not least: if plants are having healthy looking and large roots, that is indeed a sign of health and a plus, but root mass isn't everything. Tomatoes are a fruiting crop and we want good yield of fruits, not break any records in root mass - don't we? The relation between root mass and actual sprout size and finally yield, - also depends on balanced nutrient composition. The better, actually adequate and balanced the nutrient is (in the long run), the less root mass is needed to produce high yield. Root mass expands in relation to plants size AND nutrient availability in a nutrient solution (actual uptake).

Conclusion: you may consider a NFT or any other solution instead of your initial ebb/flow setup. Nothing wrong with that - but keep in mind, that while needing much less media on one hand, you need much more sophisticated (and expensive) hardware on the other. Technical or power failure may be fatal here (while it will not necessarily be with ebb/flow) And you will consume notably more energy as well...

Thanks very much for those comments - I guess I'm going to have to think about this some more, and possibly compromise with a smaller media-filled trough (cheaper), or maybe experiment with some plants using both possibilities (with/without media), and just see I guess.

Right, best is to consider all facts (and hidden unknowns) first. Think it over again, evaluating advantages vs. disadvantages, - and why not having "two strings to one's bow"... to find out which is best ;-)

Those look like very white, healthy roots to me, so that is very interesting indeed: clearly, direct air is not necessary as such, just oxygenated solution.

>> my timer has 14 on/off settings per 24 hours. this allows me to run the timer 2-3 minutes every 1.1/2 hours to 45 minutes during daytime plus one time at about 2 in the morning. Traditional EnF is something like 15 minute flood every 4 - 8 hours.

Sounds very promising, the main question would be then: how long does it take the roots in any potential clumps (once the solution has ebbed) to use up the oxgen - more frequent than usual flooding might prevent this happening as you suggest, only experience could resolve this question, how often would be enough.

I'm intending to start with seeds in rockwool or whatever this time around, and so I can monitor how things develop right from the start (no additional medium). The moment it looks like a no-go I can always throw perlite at them at any time and probably be OK. It's an interesting question - I'll report back here how things are going if you like. I normally start the seeds off in early January, so I'd expect some indication of disaster certainly (!), pretty soon after that.

>>why not having "two strings to one's bow"... to find out which is best ;-)

Good advice: I might well add perlite to a few plants very early on to compare with those with roots dangling out of the rockwool (covered pots obviously), probably sensible otherwise just because they might survive without medium doesn't mean they wouldn't do better with medium.

Yep - that would apply to all the moist roots that are dangling in contact with air, true enough - probably most of them. I'm just fretting a bit about those roots that end up inside a big clump of other roots once the solution has ebbed away. Frequent flooding should fix that too, one would hope. A no-medium, "Frequent Flooding" technique - now that sounds quite catchy :)

If using any E/F based system, there is a strict need of enough media to keep the roots moist and "in shape". Reminder: the basic idea here is of only needing a few short cycles a day (saving energy) and using a very simple and reliable technology to perform this task. The price for this technique is (unfortunately) a bigger amount of media. I really don't see any sense or benefit in using E/F with less media but more frequent E/F cycles just for the benefit of saving media. No-one has ever modified this technique in such "hybrid " way - and I guess with very good reason. In theory it may sound original and interesting but in practice, technological hybrids often lack performance and reliability. Firstly you only see the advantages of both but forget to double the disadvantages and risks.

With aeroponics for example, one pushes it truly to the next level, using a powerful pump, short but frequent spraying (misting) cycles and literally no media in the root zone. But that's a different story, and here we deal with a well tested and approved concept and technique. DW, on the other hand is really low tech - but very reliable because of the roots being permanently in water.

Sorry to be rather strict and blunt about the topic, but in this very context I see the idea of a modified E/F system with more frequent E/F cycles as non-plausible and even a contradictory solution. All due respect for any different personal approach, preference or mindset- I clearly see it as a NO-GO from this end. When I said earlier that it is a good thing to having two strings to your bow, I wouldn't recommend adding just any string that isn't up to the the task. Because it actually would most probably mess it all up when deployed ;)

I think this issue can only be resolved by actual experiment, and I'm happy to have a go. I intend to start with seeds indoors in January as always, this time though just using rockwool cubes inside the 5" pots the plants are normally grown in before they go out to the greenhouse in late April. The pots will stop roots from different plants from getting tangled (assuming things get that far!). They will be be covered at all times obviously, and will flood via the hole in their undersides.

Point being: I'll be able to keep a close eye on those roots the moment they start to poke beyond the cubes. If they are clearly stressed and frequent watering won't fix it, I can add medium at any time. I might well include a few pots with medium to compare growth rates.

Given the costs (financial at start, and time when cleaning at end of season) of scaling up to 20-odd large plants, I do think this is at least worth a go. No-medium, frequent flooding could be seen as a cheap, lower-tech alternative to aeroponics, for example. Or a non-starter. We'll see ;)

Anyway, I've given the idea of a E/F system without media another thought, because the idea itself of using less or no media with simple and reliable technology is worth it for sure. But unfortunately with the same result concerning the thoughts that came up until now:

It doesn't make any sense as long as it is neither fish nor meat. Why ebbing a Deep Water system, or why taking out the media of a E/F system anyway , knowing that both "constants" are given and used for a good reason!?

1. In D/W the stable water level not only supports the roots (as in free floating through higher density of water) it guarantees permanent water and nutrient supply.
2. IN a E/F system as mentioned, the media not only supports the roots but keeps humidity for an extended period. So why depriving the roots from (either one) of these very essential needs in the first place!?

3. With an Aeroponic system, roots are indeed hanging freely and without any support - but they can at least settle and stabilize in that position and actually do cope with it rather well. The fact that they get sprayed or misted frequently doesn't affect their "adopted stability" resulted from a more or less stable condition.

4. In NFT system the CONSTANT flow in the run does the trick.

5. But if you go for-, and (necessarily) frequently F and E, you create and alternate two completely different environments. You then force roots from free floating state in deep water, back to hanging freely in air. That must obviously stress roots and plants a bunch, because they can't settle for any stable position, nor can they get used to floating freely in denser gravity of water.

5. Not even speaking about the lack of any benefit or advantage for roots and plants that could be expected from such specific technique, - actually experimental modification(s)
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AND YES, I have a better alternative In Petto to using no- or little media! A rather uncommon but already tested and good working method that one may call "recycling Deep Water system". It's actually based on multiple buckets but can be used with single growing containers (used for E/F setups) as well. Using a secondary reservoir to recycle and oxygenise, furthermore a small inlet and a bigger outlet overflow (either individual for each bucket, or a single-one if using one big growing container). I could describe it more in detail, perhaps giving some references or providing some 3D sketches I've done previously (after a existing model). Well, obviously only if that wouldn't be seen as trolling or perhaps chasing good people away from this place out of crazy jealousy. Most certainly because of fear of loosing their title of "squinter Top Expert" among blinds. I mean you obviously provoking my sarcasm here LOL.

Btw. for those who won't fall for these "innuendo attacks" targeted at my person, - kinda pathetic aren't they!? They are only intended to devaluating the basically founded and mostly correct information and help I always try to provide, - by untruly and unfairly putting my identity and person in discredit. My knowledge doesn't come from any outdated articles from some Hydro-Dinosaurs either, and I don't see at all how such thing could even cross someone's mind. Too my knowledge, I haven't mentioned or used anything that might lead to such- or other wired conclusions. I am actually a professional designer of hydroponic setups and developer of nutrients. I have been designing and building dozens of setups of any kind and based on all known principles. That is why I really can't afford to lean on outdated information or knowledge - but am using all I can get which mostly consists out of up-to-date info and knowledge, even recent scientific research. And most importantly, it's my pleasure to hopefully helping trough my very own experience and last but not least, rather well developed SKEPTICISM (which for some reason that I can't grasp - doesn't seem to be appreciated at all) that I have painfully acquired over the years ;-)

I’d considered keeping the solution in the trough essentially, but for some reason in my conditions, if I don’t keep a vice-like grip on the nutrient solution, within a day I’ll see a grey haze form and the pH screams upwards by the hour. Long story short (involving two ozone machines that both broke), I use a UV-based sterlisation unit to keep the solution crystal clear, and stable. This is the main reason I didn’t fancy a ‘shallow water culture’ involving keeping solution in the trough permanently, i.e. not necessarily a very good reason really and wouldn’t apply to everyone.
>>But if you go for-, and (necessarily) frequently F and E, you create and alternate two completely different environments. You then force roots from free floating state in deep water, back to hanging freely in air. That must obviously stress roots and plants a bunch, because they can't settle for any stable position, nor can they get used to floating freely in denser gravity of water.

You could well be right. I’d just say this: those tomato plants I transferred from peat to Perlite earlier this year were very pot-bound due to delays in setting things in a stable fashion (see my comments above), and so I had to put them through hell and back getting the fine roots disentangled from the peaty bits. They not only survived, they thrived. I suspect those tomato plant roots are not as delicate as one might suppose then, and gently wafting up and down a few times a day as water levels rise and fall might be just fine. Or not, depending on variety etc. perhaps.

>>"recycling Deep Water system". It's actually based on multiple buckets…

This I like the sounds of, and would be very interested in hearing more. My main reason for not going for NFT or related was the cost of running a pump 24/7. Otherwise, I’d be interested in hearing of this idea, and would appreciate it very much if you would expand a bit more – those 3D sketches sound intriguing.