# So-called "Heavy Root Feeders" - Fact or Fiction??



## Qwe

Thank you for doing this! I love experimentation threads...


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## keymastr

Just curious, what does the "plus" include in Osmocote plus? I have a big bottle of regular Osmocote and while I have never used it in an aquarium I found it ineffective at growing flowers in the garden. My local garden dude turned me on to some stuff called "Garden Cote 6" which makes my flowers bloom like crazy. He claimed that when Osmocote was bought out a few years back that they removed some of the more expensive micros but I have nothing but his word for that. There are a few things in the Garden cote that are not in regular Osmocote so I was just curious if that was what the plus was.


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## burr740

The Plus has micros, in addition to NPK. 

Not positive, but I believe the only thing missing in the new recipe from the old is calcium. Somebody correct me if that's wrong.


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## plantbrain

Osmocoat will leach out and fertilize the entire tank. Also, EI is not non limiting, that's a bad assumption:wink:

So a tank with say MTS or ADA aqua soil and EI vs a tank with just ADA AS or MTS, or just EI............will have slower rates of growth compared to EI + a rich sediment type. 

I do not think anyone has issues growing Crypts or swords really if they take decent general care of them. Large roots, they both come from streams and rivers where they would get washed away. A good reason to have large roots. 
Then once the water recedes........they are left high and dry.........they need a strong root system for nutrients/water uptake. 

Both Genera have rhizomal type roots and runners, good for storage and resprouting, ability to send runners to better habitat locally and to over winter long droughts/adverse conditions.

A simpler test is to use a sponge at the neck of a flask to place the plant's crown in and add fertilizer in the flask or not.........then add a non limiting fertilizer to the water column. This keeps the root fertilizers separated and the roots isolated. While providing plenty of nutrients to the leaves. 

The other simple thing to do, cut off the roots and see if the rates of growth are the same in rich sediment with rich water column. 

http://www.prirodni-akvarium.cz/en/...ophytes growing in a nutrient-rich stream.pdf


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## Mariostg

That should become a popular thread. . I have a rather large sword in my 75. So very interested.


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## kep

Subscribed!


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## Maryland Guppy

plantbrain said:


> Osmocoat will leach out and fertilize the entire tank.


 This might be the case. I am now subscribed too.

This is an awesome test.


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## Frank H

very interesting! Looking forward to seeing results.


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## Chrisinator

That should be a really fun experiment!


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## chiefroastbeef

very interesting! thank you for doing this!


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## lee739

plantbrain said:


> Osmocoat will leach out and fertilize the entire tank. ...... http://www.prirodni-akvarium.cz/en/...ophytes growing in a nutrient-rich stream.pdf


If so, and both sides grow well, the experiment will still yield useful results.....


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## Audionut

Another interested party here. Threads like these are what makes forums so great.


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## roadmaster

plantbrain said:


> Osmocoat will leach out and fertilize the entire tank. Also, EI is not non limiting, that's a bad assumption:wink:
> 
> So a tank with say MTS or ADA aqua soil and EI vs a tank with just ADA AS or MTS, or just EI............will have slower rates of growth compared to EI + a rich sediment type.
> 
> I do not think anyone has issues growing Crypts or swords really if they take decent general care of them. Large roots, they both come from streams and rivers where they would get washed away. A good reason to have large roots.
> Then once the water recedes........they are left high and dry.........they need a strong root system for nutrients/water uptake.
> 
> Both Genera have rhizomal type roots and runners, good for storage and resprouting, ability to send runners to better habitat locally and to over winter long droughts/adverse conditions.
> 
> A simpler test is to use a sponge at the neck of a flask to place the plant's crown in and add fertilizer in the flask or not.........then add a non limiting fertilizer to the water column. This keeps the root fertilizers separated and the roots isolated. While providing plenty of nutrients to the leaves.
> 
> The other simple thing to do, cut off the roots and see if the rates of growth are the same in rich sediment with rich water column.
> 
> http://www.prirodni-akvarium.cz/en/...ophytes growing in a nutrient-rich stream.pdf


 
Thank's for the link Tom


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## seandelevan

Fascinating


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## Hoppy

This should be interesting! Both sides should have very nearly the same water column nutrients, but the Osmocote side should have more nutrients available to the roots, but it might not be much more. The substrates are in water, so nutrients can migrate both ways - into the water and from the water to the substrate. So, if the growths are nearly identical between the two sides it might show that the leaf feeding is adequate for the "heavy root feeders", but it might also show that nutrients migrate between the substrate and water freely enough to feed the roots even though there is no substrate fertilizer there.

This is kind of like the NASA efforts to find evidence of life on MARS - once the experiment gives positive results, you have to make sure those results can't have occurred for reasons other than what you were trying to prove.

That just makes it more interesting!


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## Beefy

Nice start on an interesting experiment. Lots of possible future permutations including high CEC substrates with/without root feeding, low water column fert addition with/without root feeding, and macro+micro tabs (osmocote) versus micros only (Flourish Tabs).

Wild prediction: at least one plant species will do poorly with the Osmocote due to ammonia burn.


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## burr740

plantbrain said:


> Osmocoat will leach out and fertilize the entire tank.


Thanks Tom for the always valuable info. 

Regarding the quoted part: I understand that, but does it even matter? The leeched out nutrients should be the same as any other water column ferts at that point, right? 



Hoppy said:


> This should be interesting! Both sides should have very nearly the same water column nutrients, but the Osmocote side should have more nutrients available to the roots, but it might not be much more. The substrates are in water, so nutrients can migrate both ways - into the water and from the water to the substrate. So, if the growths are nearly identical between the two sides it might show that the leaf feeding is adequate for the "heavy root feeders", but it might also show that nutrients migrate between the substrate and water freely enough to feed the roots even though there is no substrate fertilizer there.


I thought about that too. If both sides do well, even though we may not know for sure if they fed from the roots or the water column, it will still serve to illustrate they dont really need root ferts when there is an ample supply in the water. Which is the primary question the experiment is trying to answer.

Thanks again for suggesting something like this in that other thread. You actually gave me the idea for this incredibly fun experiment. 



Beefy said:


> Wild prediction: at least one plant species will do poorly with the Osmocote due to ammonia burn.


Haha, I did use quite a bit. Actually I removed maybe 10% after those pics were taken because it looked like such a whopping amount. :icon_eek: So there's not _quite_ as much as what's in the pics. 

I've done about this much a few time under a specific area for carpeting plants with good results, but never a whole tank's worth, or in this case half a tank's worth. Time will tell.....


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## roadmaster

Believe the Osmocote will take some time to begin leaching nutrient's(slow release) compared to water column dosing which would work faster for plant's benefit.
I am advocate for both substrate loading/feeding and water column dosing together for it produces the result's I want.
Plant's are in win/win situation and so long as too much light is not used,,leaves only CO2 to get right.


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## Hoppy

I hope you will take a photo of the tank every week to 10 days and post them, so we can follow the progress. 

Rarely does a single experiment prove much. Proof of something usually take numerous different experiments. But, this should be able to show that the plants you are using can be grown well, equally well, almost as well, etc. whether you use substrate fertilizing or not, as long as you are dosing the water column adequately.


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## burr740

Yeah the plan is to post weekly updates.

Took some PH readings. CO2 looks to be OK. The guppies are lively, none have died. I was a little concerned them being fry.

First one is degassed tank water. This is higher than any of my other tanks, which usually range from 7.6 or so to 8. I wonder why.




















I think I can get it lower because one of the reactor bottles is producing less than the other one for some reason, less than what a bottle normally does for me. I'll change that one first when the time comes.


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## chicken

This should be interesting. I look forward to updates.

I'm curious about why you chose to use one divided tank instead of two separate tanks?


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## Beefy

chicken said:


> I'm curious about why you chose to use one divided tank instead of two separate tanks?


To have an identical water column and lighting.


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## burr740

chicken said:


> This should be interesting. I look forward to updates.
> 
> I'm curious about why you chose to use one divided tank instead of two separate tanks?


What beefy said. To have exact same water column, light and co2.


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## burr740

*First Pic, Day 1*











*1 Week*










In the left corner is a bit of willow moss on a ss screen. It's hanging flat against the back glass.


Back Row - Both the swords and the AR on the right have grown significantly more than the left.

Middle Row - Not much difference in the crypts. They've all grown some and are sprouting new leaves. The compact hygro on the left might actually look better.. Both sides are coloring up well. 

Front Row - About the same on both sides. Having a slight diatom outbreak. Mostly on the stauro's old leaves. Oddly enough, the stauro on the left side has a lot lot more than on the right does. DHG is going through something of a melt. Much of the old growth is dying, new sprigs are emerging though so I think it should be fine.


Added two otos yesterday. Say Hello Mr Otto.











Side Comparisons:

L
R


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## Hoppy

Looking good! I'm looking forward to tomorrows pics!


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## burr740

Progress report coming tomorrow^


That 8.2 PH didnt seem right, so I re-calibrated the pen. Turns out it was off by a pretty good bit.

Latest readings -



















Blurry pic, this one otto thinks he's a guppy. :red_mouth He likes to frolic around with them in the upper parts of the tank.


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## burr740

*First Pic, Day 1*











*2 Weeks*











*Observations:*

Back Row - The swords on the right continue to outpace the ones on the left. Probably the most significant difference so far out of all the plants. The AR on the right continues to be a little better as well.

Middle Row - Noticeable difference between the two outside crypts. Ones on the right are exhibiting larger growth, and also more new leaves. The inside crypts closest to the middle, the wendtii browns, the one on the left is actually outpacing the one on the right by a considerable margin.

Compact hygros are about the same. I accidentally uprooted the two in front pouring water from a bucket. So they've sorta been reset. 

Front Row - Very little difference in any of these. The DHG continues a very slow rebound. The left side may look a tad better than the right.


*Side Comparisons*


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## Hoppy

This is like the first 5 minutes of the first quarter in a NBA game. You can't begin to predict the winner yet! But, I'm about ready to put my bet down.


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## burr740

*3 Weeks*











*Observations:*

Back and middle rows: Same basic trends. The right side continues to do better than the left. Except for that one crypt closest to the center, where the left one is still outpacing the right, for some strange reason. 

Front row: Still about the same on both sides. Except the Stauro on the right is just beginning to sprout side shoots, and each stem has a couple more leaves per than the left side.


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## Hoppy

At this point the difference certainly isn't dramatic, other than with the sword plant.


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## burr740

Hoppy said:


> At this point the difference certainly isn't dramatic, other than with the sword plant.


There really isnt. Although it's more noticeable in person as far as the crypts and AR.

I actually expected a big difference in the S repens and DHG too. So far there's not much at all, except what I touched on earlier with the Stauro, which is minimal at this point.

The downoi I had no idea about, just had a few extras and stuck them in there.


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## burr740

*Week 4 Update:* Everything trending the same as before. Will do a new batch of pics next week.


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## Hoppy

It looks like a tentative conclusion is that substrate fertilizing certainly does no harm, but it isn't necessary for getting good growth of "heavy root feeders". As Tom Barr points out many times, it has to be better to provide nutrients for both leaf feeding and root feeding, to give the plants a choice. But, it isn't crucial.

Another month or so and we should be able to reach a consensus on that. (or not!)


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## KnownSyntax

Looking forward to seeing what happens! I too find it very interesting on if these heavy root feeders are truly dependent on the nutrients in the soil vs. in the water column.

I'll be totally using whatever results you get on my 55 gallon tank when I set it up (probably two or more months away if even that soon).


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## HybridHerp

I do wonder though if there are some species that are more requiring of nutritious substrate than others. Like Erios and the like, or if the plants maturity changes its needs.


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## Hoppy

HybridHerp said:


> I do wonder though if there are some species that are more requiring of nutritious substrate than others. Like Erios and the like, or if the plants maturity changes its needs.


It just isn't possible to do this type of test with every single plant species. So, it is possible, however improbable it is, that there are some plants that do have to have substrate feeding.


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## burr740

At this point based on the extremely small sample size, I think it's safe to say swords might actually need it, and many other species will do better with it, if only slightly, even though it may not actually be necessary.


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## philipraposo1982

For the cost of diy root ferts there is really no reason not to add them to any planted tank IMO.


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## Patriot

Interesting


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## Hoppy

philipraposo1982 said:


> For the cost of diy root ferts there is really no reason not to add them to any planted tank IMO.


I agree, but most hobbyists are convinced that "heavy root feeders" absolutely have to have substrate nutrients or they do very poorly. This experiment, to date, falsifies that "fact". There never was any controversy over whether plants can do better with both substrate and water column fertilizing. They can do better that way, but how much better varies from species to species. And, there isn't much data to say which species are in the "do much better" group.


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## HDBenson

^^ This being said ^^ it might be time for some one to try this experiment with just swords or, just crypts. Plants traditionally deemed "heavy root feeders". For example: a 5.5g 2-3" substrate with five C. wendtii in each one with just inert substrate. One will have o+ BURIED and the other o+ on top of substrate. This might provide a better idea: same nutrients in different locations i.e. roots/watercolumn.


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## plantbrain

Crypts and swords I've kept for almost 40 years now. They do quite well, get massive etc in plain sand tanks, there's a lot of evidence of that.

So I'm curious, why the cotton picking great honry toads, would you want a larger.........Amazon sword plant? 

It takes TIME for them to grow and as they grow, they get massive, so does the root system............a plant with 6 months of growth vs say 1 month of growth is not comparable. Adding more ferts to a specific location needs to account for the biomass and the plant's establishment also.

A plant that weighs say 5 grams wet weight(80% shoot, 20% root) vs a plant that weighs 25 grams wet weight(60% shoot, 40% root) are going to respond differently also.

Adding more ferts to the water column or the sediment.

Adding the SAME amount of ferts to the sediment as the water column also presents a problem. If I dose say 200 ppm as DIY sediment ferts...........vs 20 ppm a week, are those the same?

No.

Many assume that is the case. It's not.

DIY/Brands etc, there's not really a good argument to NOT add sediment ferts. Likewise, there's not a good argument to not add water column ferts either. As far as plant preferences..........most plants will take from both locations and grow best/larger/faster.

Now some folks whine and argue in favor of less ferts= best quackery.......so they like to justify lean ferts to control growth, that is a legitimate argument I would suggest. But less is not best for optimal growth, that is quackery. Older myths die hard. Some have gone to sediments to get around this, thinking the sediments can hold 200-500 ppm of NH4 and that is some how "lean" since they lack the skills/tools to measure sediment ferts. Not the most logical mentality. But the limitation to control the rates of growth for management has merit. 

Sediments general lose NH4 over time, NO3 does not bind to sediments. So you can use sediment ferts and argue that it is the NH4 vs NO3 differences you see with "preference". Thus the form of N is the critical factor rather than location per se. 

At a more basic hobbyist level, what provides your management with better growth and easier care? Likely just stick with that. So add to both locations, both methods are easy, both methods provide 2 types of N, both provide short and long term nutrient supplies. If you forget to dose the water, the sediment is a back up. We all forget to dose. 

Back up plans and redundancy. Always wise:icon_idea

So standardize the sediment ferts/amounts and measure them in equal NPK for the water column. Say 10 weeks. 200 ppm of sediment N as NPK and water column at 20 ppm a week as N as NPK(say 20-5-20).

NH4 vs NO3 is still an issue, but at least you are much closer. 
Emergent growth allows you to get around lighting,and CO2.........and you can add what ever to the pot/flask and it has nowhere else to go, so you can use NO3 and NH4 in those types of emergent test. 

In other words, you need to split up the experiment into several parts to address each factor. Trying to do it all in one test is not going to isolate the confounding factors. Most test are actually a series of test, you go down and rule things out, step wise, one at a time. Once you have exhausted the alternative confounding factors.....then you are left with a pretty good idea hopefully. 

Hope this helps and clarifies the issue, helps provide a basis for testing such things. Most of these test, hobbyists CAN DO.


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## HybridHerp

^I agree with what Tom said, even if some of it goes a little over my head/I'm too lazy to think about the specifics of what was said atm lol


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## adive

Interesting experiment. Thanks.

Just want to relate my experience with swords: I have a 50:50, river sand:commercial high CEC substrate, low tech tank. With just liquid fertilizers the swords never took off. Then I started adding root tabs and the swords really took off. This is a no CO2 injected tank, no Excel/glut either.

Even now, after about 2 months the root tabs nutrients deplete and growth "stops" and new leaves stop emerging. Then I add more tabs and the growth visibly resumes. Hope that helps.


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## Zorfox

I personally like the experiment. Clearly it couldn’t be used as an acceptable graduate school thesis. However, there is information that can be gleaned from this. The results will suggest whether substrate fertilizers are helpful for the plants included.

Real world data is important. Secondary data can be used to direct efforts of collecting future primary data. The conditions are similar to what other hobbyists may have. When the test is complete others could use the results to select plants that would be viable candidates for further study. Then the confounding factors could be better controlled to improve accuracy of the conclusion.


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## Hoppy

adive said:


> Interesting experiment. Thanks.
> 
> Just want to relate my experience with swords: I have a 50:50, river sand:commercial high CEC substrate, low tech tank. With just liquid fertilizers the swords never took off. Then I started adding root tabs and the swords really took off. This is a no CO2 injected tank, no Excel/glut either.
> 
> Even now, after about 2 months the root tabs nutrients deplete and growth "stops" and new leaves stop emerging. Then I add more tabs and the growth visibly resumes. Hope that helps.


The "liquid fertilizers" consisted of what? Your results could also demonstrate that you were not dosing enough of something, so adding the root tabs eliminated that shortage, until the tabs were used up.


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## burr740

One thing Im curious about is how the results might vary if the tank was being harder driven, light wise.

Say 100+ PAR or so...


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## adive

Hoppy said:


> The "liquid fertilizers" consisted of what? Your results could also demonstrate that you were not dosing enough of something, so adding the root tabs eliminated that shortage, until the tabs were used up.


There are 2 bottles that I got that are locally made. One is a green liquid and the other is orange-ish (this is mainly ferrous) if that means anything. They have given me good results at a fraction of international brand prices. The exact ingredients are not mentioned on the bottles. But basically contain "macros, micros and traces".

I am not a plant scientist or anything like that  but these ferts gave me good results so I use them. I had also thought about buying dry ferts but wasnt sure about reliable sources and didnt want to get into figuring how to source the best chemicals, etc. so i am happy with these ferts.

One more point: the stem plants were doing good which also indicates the liquid ferts were good. I never put root tabs near the roots of the stem plants though its possible the root ferts leached out and the stems got'em.


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## burr740

*Week 6*




















Left/
Right




















The crypts on the right have all grown more leaves than the left, but the difference is not dramatic at this point.

Not sure why the DHG is struggling so bad, not enough light maybe? The right side has overtaken the left side now, such as it is.

The stauro on the left is taller, but the right side is denser, and has more side shoots.




















Surprising to me is after the sword plants, the most dramatic difference yet is with the AR. The right side is flourishing while the left side is looking rough.

Here you can see all four plants. It's hard to get a pic, Im trying to hold the plants in front down.


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## Hoppy

It looks like all the plants grow well on both sides, except the hairgrass. But, the swords do better with the substrate fertilizing. Is the AR doing best on the fertilized side? It seems to be demonstrating Plantbrain's contention that having both the substrate and the water fertilized gives the best results. Right?


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## Patriot

Maybe the same test could be done using two smaller sperate tanks under the same light? That way you don't get fertilizers in the water column.


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## burr740

Hoppy said:


> It looks like all the plants grow well on both sides, except the hairgrass. But, the swords do better with the substrate fertilizing. Is the AR doing best on the fertilized side? It seems to be demonstrating Plantbrain's contention that having both the substrate and the water fertilized gives the best results. Right?


Yes, the AR is doing better on the side with the Osmocote+.



Patriot said:


> Maybe the same test could be done using two smaller sperate tanks under the same light? That way you don't get fertilizers in the water column.


Well the point is to have ample ferts in the water column. To see if these plants actually need additional supplements at the roots, or if water column alone is enough. Im dosing EI levels of NPK and csmb here. The only difference is the right hand side has Osmocote+, the left side is inert sand only.


The one variable which Hoppy touched on earlier, is the plants on the left could still be feeding from their roots via ferts that make their way into the sub from the water column. 

That's OK too. From a hobbyists standpoint, we may not know exactly why the plants on the left are doing well, but we are still getting a good indication whether they actually need (or do better with) root supplements when there is ample ferts in the water column.


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## Hoppy

At this point I think you have already falsified the claim that "heavy root feeders" need substrate fertilizing. They do better with a nutrient load in the substrate, but still do well without it. Eventually the osmocote will run out of ferts, and then the test is no longer a test.


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## burr740

Yep, Im pretty surprised actually. I expected some of the plants on the left to seriously struggle, much like the AR seems to be.

Even the swords on the left are healthy and not deficient. They are just growing slower and smaller than the ones on the right. Crypts are pretty much the same, only not as much difference between sides.

Will continue for another month or so. Then document as best I can the difference it made for each species.


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## ichthyogeek

This is very interesting. I haven't heard about many heavy root feeders before aside from the Amazon swords and crypts, so this is new to me. Do you think that the rumor may have something to do with the fact that many of those "heavy root-feeding" plants are more bog plants, or plants that can transition from emersed to submersed and back? Because the plants have naturally large roots due to the constant submersion and emersion?


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## THE V

My first guess would be that the "heavy root feeders" are adapted to nutrient poor tropical or subtropical waterways. The large root mass allows for them to scavenge up nutrients better. It could also could be an adaptation to swiftly moving water. The large root system helps anchor the plant to the substrate and/or keep the substrate from washing away quickly. 

In your test you have a localized area of higher nutrient concentration in the substrate with the osmocote. This higher nutrients allows the plant to grow faster. You'd probably have a similar result if you used separate tanks with a slightly higher water column fertilizing dosing schedule in one vs. the other. 

If you want to be really scientific about it can do a classic root/shoot comparison. At the end of the test remove all the of the plants, desiccate them, and weigh the dry matter of the root vs. the shoot. Of course this kills all the plants. I did this experiment in my Soil Science lab in college. 

I've grown massive swords and crypts in my low-tech 125g setup for years with a sand/gravel substrate and dry ferts to the water column.


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## burr740

Starting to re-home some of these plants and break the tank down. So this will be the last round of pics. 

*8 Weeks*



















Left side (inert)
Right side (ferted)



















Better shot of the crypts with the stauro and downoi gone. Surprisingly small difference.



















I'll take a good shot of the AR when I pull the Compact Hygro in a day or so.


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## Xiaozhuang

Just dropping in to say thanks to burr740 for running the experiment~ 

It's nice to have a side by side comparison


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## Hoppy

Xiaozhuang said:


> Just dropping in to say thanks to burr740 for running the experiment~
> 
> It's nice to have a side by side comparison


I agree! This was a very interesting experiment, with results not quite what I expected. An obvious difference between the two sides is the bigger sword plant growth, even though the left side plant looks good, the substrate fertilized plant grew significantly faster. A better look at the AR plants will be interesting.


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## mattinmd

Agreed, I would have expected a larger disparity myself...

I guess it goes to show that while root feeder can, and will, take nutrient from the substrate, they don't really *have* to.

Obviously the plants on the left had access to sufficient nutrients from the water column, which is why they are healthy.

The plants on the right had access to the same water column fertilizers, but also had access to the substrate fertilizers, allowing the more nutrient hungry plants to grow larger, faster. I'm still surprised that more of the plants on the right didn't show higher growth, but I guess the water column was enough to be completely non-limiting for them.. That is EI's goal anyway....


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## Italionstallion888

I would have a hard time taking that tank down. I would remove the divider and scape it up lol

thank you for doing this. Very interesting read. I say split it out between 2 tanks and take this even further. Bravo sir.


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## klibs

Burr you are truly a man of science


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## burr740

So Ive re-homed just about everything now. Here's the AR. 



















The other day on a whim I decided to take another PAR reading (thanks again for the meter Hoppy). If you recall from pg 1 it started out mid-60s. Well now it's in the mid 40s. Turns out the wal-mart "plant bulb" is only putting out ~15-16. It must be a real piece of crap to drop that much in two months. I like the color rendition though. Gonna replace it with something better soon. Anyone know if there's a good reddish T8 out there?



Italionstallion888 said:


> I would have a hard time taking that tank down. I would remove the divider and scape it up lol
> 
> thank you for doing this. Very interesting read. I say split it out between 2 tanks and take this even further. Bravo sir.


Hah, when I said break it down I meant take all the plants out and do something else. Im definitely gonna keep this tank going. For now it will be a staging/grow out tank until I decide what kind of scape I want to do. Thanks for the compliment.


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## Doppelgaenger

Something I'll add at this point now that the experiment is over...

I spent a good 7 years raising olive trees, and when you have a plant that needs nutrients 3 days ago because it's starting to look shabby, you do a foliar spray, not a root application. Better to dose where the ferts are needed than to let them take it up thru the roots. And that just said, I wonder how much more root mass was on the plants with the osmocote vs those that didn't grow as much? did you get a chance to study that with this test?


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## Aquatic Delight

I was wondering if you weighed the plants as group, or counted the leaves before and after if we could come to a different conclusion, or a stronger conclusion. the eye test is great but its like guessing how many jellybeans are in a bucket. you really have no idea.


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## burr740

Doppelgaenger said:


> ... And that just said, I wonder how much more root mass was on the plants with the osmocote vs those that didn't grow as much? did you get a chance to study that with this test?


I didnt take pics or document it but I did pay attn and notice when I removed everything. It was basically the same below as above. The ones that did better on the ferted sub side had larger root systems, essentially proportionate to to the differences up top.

Most noticeable of course in the sword plants. One thing that was interesting, is the swords on the inert side had a FAR less dense root system, but...the roots were considerably longer than the plants on the ferted side, like twice as long. It makes perfect sense in retrospect because the plants with root ferts didnt have to go far to feed, whereas the ones on the inert side were aggressively creeping out to find something.


Aquatic Delight said:


> I was wondering if you weighed the plants as group, or counted the leaves before and after if we could come to a different conclusion, or a stronger conclusion. the eye test is great but its like guessing how many jellybeans are in a bucket. you really have no idea.


Meh, the test was never going to be that scientific to begin with. But I would say the eyeball test in this case is a lot more significant than guessing jelly beans....pretty clear results right there in plain sight.


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## Tinanti

I have never found anything I couldn't grow well just fertilizing the water column. Not ever.


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## Hilde

Since AR has red in leaves perhaps it needs more iron dosed in the water column.


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## burr740

Got to thinking about this recently,

Here's a tank getting full EI in the water column. including csmb dosed at .5 ppm Fe 3x week, and also loaded with Osmocote+.

Where is the micro toxicity? Where is the algae and melting plants? 

Things that make you go hmm....


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## dpod

It's only one experiment, but it's good to know that root tabs will help swords and AR, but not much else as long as there's good general fertilization. I'm surprised the crypts didn't show much difference!


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## d33pVI

Thanks for bumping this thread, had not seen it before. Might need to try some root tabs for my AR and swords, as they are the only plants not really taking off for me right now.


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## Wasserpest

I always noticed with AR, if I cut it in half and stuck the top sections back into the substrate, it would always struggle for a while, until it had grown a decent root system.

On the flipside, I had a Crypt which got stuck on some driftwood as a baby, and it grow to a full, beautiful plant... with all it's roots in the water, outside the substrate.

Would be interesting to do the other test - two tanks with identical (enriched) substrate, one with water column dosing, the other without. One would expect opposite results, with the Swords and AR being the least affected?


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## bru2586320

Awesome experiment "burr740"... I have been trying desperately to source some powder ada for a shrimp, plant, Cory, with CO2 tank... I heard that it was the best substrate for a tank with shrimp, plants, and Cories... Now, I'm more inclined to get a similar sized substrate, and just add water column/tab ferts... Great experiment-(This is what I did & This is what happened)...


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## HaeSuse

burr740 said:


> I thought about that too. If both sides do well, even though we may not know for sure if they fed from the roots or the water column, it will still serve to illustrate they dont really need root ferts when there is an ample supply in the water. Which is the primary question the experiment is trying to answer.


This cannot be readily ascertained from your experiment. If both sides grow well, it could also be that what made them grow well was the root tabs (via leeching). Just because the tabs are on one side, makes no difference, for this. 

A far better test would've been the exact same thing, but in 2 different tanks, so the root tabs are only leaching in their own respective tank.


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## Hilde

I recently setup a new tank. Moved crypts which were planted in a container with dirt to the tank. The water is very soft. They melted. To me that says column dosing is important to all plants.


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## houseofcards

HaeSuse said:


> This cannot be readily ascertained from your experiment. If both sides grow well, it could also be that what made them grow well was the root tabs (via leeching). Just because the tabs are on one side, makes no difference, for this.
> 
> A far better test would've been the exact same thing, but in 2 different tanks, so the root tabs are only leaching in their own respective tank.


I don't agree. The purpose of the experiment was to see if some plants really need root supplements. Any leaching would be water column ferts like anything else so if plants really needed direct ferts in the form of a root supplement that would have been illustrated in the group on the right.


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## burr740

HaeSuse said:


> This cannot be readily ascertained from your experiment. If both sides grow well, it could also be that what made them grow well was the root tabs (via leeching). Just because the tabs are on one side, makes no difference, for this.
> 
> A far better test would've been the exact same thing, but in 2 different tanks, so the root tabs are only leaching in their own respective tank.


Im sure the root tabs leech into the water column, but what difference does it make?

The water column is getting full EI. If the root tabs leech, it's just more nutrients in the water column. The left side still has nothing at the roots.


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## HaeSuse

houseofcards said:


> I don't agree. The purpose of the experiment was to see if some plants really need root supplements. Any leaching would be water column ferts like anything else so if plants really needed direct ferts in the form of a root supplement that would have been illustrated in the group on the right.


Negative.

Your conclusion includes (though maybe you missed it) the assumption that "heavy root feeders" literally feed directly from the tabs to the roots. The whole experiment assumes that. It could just as likely be that "heavy root feeders" eat just as readily from the water column, and that the presence of root tabs helped them in another way. Meaning, maybe "heavy root feeders" DO benefit from root tabs, but the WAY they benefit from root tabs is being able to consume the ferts released by the tabs into the column. Maybe they ARE heavy feeders, but not heavy ROOT feeders. Which, if true, would yield these results. No real difference between the 2 sides of the tank. Whereas, if this assumption is not true, then if you split the tanks up, then the root tab tank would do better than the no-root-tab tank.



This experiment absolutely, 100%, does not prove or disprove the above assumption. The only way to do so would be to put them in separate tanks. It may seem stupid that this assumption would need to be tested... but, most people assumed "heavy root feeders" needed root tabs to begin with, so, why would it be so crazy for the result to be: "Heavy Root Feeders are INDEED heavy feeders, but it doesn't really matter whether you supplement their diet with root tabs, or extra column ferts".

It's like what @Hoppy said a bunch of posts back.... running this experiment, and then attempting to peg the results to a specific set of theories or reasons, is going to be very, very tough.

Really, the best way to go would be 4 identical tanks, with the only delta between them being: 


tank 1 has no ferts at all
tank 2 has just root tabs
tank 3 has just water column ferts
tank 4 has both root tabs and water column ferts


I believe the results WOULD turn out the same. In other words, I fully believe the hypothesis being opined here- that root tabs are wholly unnecessary, when dosing EI or PPM (or any other adequate water column fert dosing regimen). However, from a purely laboratory science perspective, I don't think this has been proved, using the shared tank method.

Bump:


burr740 said:


> Im sure the root tabs leech into the water column, but what difference does it make?
> 
> The water column is getting full EI. If the root tabs leech, it's just more nutrients in the water column. The left side still has nothing at the roots.


As @Hoppy mentioned, ferts are not a one way street. The tabs leech into the column, and the ferts leech into the substrate. So, in other words, just putting EI into the tank to begin with, skewed the results, because the roots DO have ferts at the roots. They have EI ferts at the roots. Unless, maybe, you created some sort of film on top of your substrate, hermetically sealing the substrate from the water column. Which, clearly, you did not do.


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## houseofcards

HaeSuse said:


> Negative.
> 
> Your conclusion includes (though maybe you missed it) the assumption that "heavy root feeders" literally feed directly from the tabs to the roots. The whole experiment assumes that. It could just as likely be that "heavy root feeders" eat just as readily from the water column, and that the presence of root tabs helped them in another way. Meaning, maybe "heavy root feeders" DO benefit from root tabs, but the WAY they benefit from root tabs is being able to consume the ferts released by the tabs into the column. Maybe they ARE heavy feeders, but not heavy ROOT feeders. Which, if true, would yield these results. No real difference between the 2 sides of the tank. Whereas, if this assumption is not true, then if you split the tanks up, then the root tab tank would do better than the no-root-tab tank.
> 
> This experiment absolutely, 100%, does not prove or disprove the above assumption. .


No sorry your still wrong. The experiment IS based on the assumption that heavy root feeders feed from the roots and those plants need root tabs. Once it's in the water it makes no difference whether those ferts are provided in dry, liquid or leached root tab nutrients. I honestly don't see your point. 

Are you saying there's some magic dust in the root tabs that makes it a better water column fert then the liquid, dry ferts that most dose?


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## HaeSuse

houseofcards said:


> Are you saying there's some magic dust in the root tabs that makes it a better water column fert then the liquid, dry ferts that most dose?


For one, maybe you picked too low of an EI dosage. Meaning, the crypts were fine and dandy with exactly what EI dosage you chose, even if you left root tabs out entirely. BUT, maybe if you had done 25% more, then they would've done better. AND, subsequently, they RECEIVED the extra 25% from the leeching of the tabs into the column. Is this likely? Nah! I don't think so! But did you set your experiment up in such a way as to definitively say one way or the other? No. You did not. If the above was true, in your experiment, both sides of the tank would grow the same. But in MY experiment, the EI tank would look less lush than the EI + tabs tank. Does that at least make sense? I could dream up a few other ways that the results could be skewed. Maybe there is some specific micro nutrient that is in X concentration in the EI Micro mix you are using, but is in triple that concentration in the tabs. And maybe, just maybe, crypts really like that one specific compound/element/nutrient. Your experiment would also not rule THIS out, whereas mine would. Lemme think.... How about this one (remember, I'm just a hobbyist, not a chemist)? Maybe the root tabs have TOO much of some specific nutrient, and if you had split the tanks up, the EI + Tabs tank would have done WORSE than the tabs alone tank. Your experiment also does not prove or disprove that.


For two, yes, I am saying that. That's the whole point. The science doesn't disprove it. You can castigate me as a lunatic, or sprinkle magic dust in your response all you want, but science is science. The whole thing you are attempting to disprove, "Heavy Root Feeders benefit from Root Tabs", is premised on the idea that "plants that primarily feed via their roots might benefit from solid based chunks of NPK+Micros stuffed beneath their feet." When, in reality, the roots, in an EI dosed tank, are constantly submerged in liquid that is filled with NPK+Micros. The whole idea that root tabs might be beneficial (even when you are dosing dry ferts directly to the water column), is utterly absurd. THAT is magic dust, friend. If "heavy root feeders" needed root tabs, then the entire hydroponic industry wouldn't work. The entire idea is bunk and hogwash and fairy dust. Roots drink nutrients. Roots are not going to care whether the nutrients are suspended in the water column (which reaches the roots), or are sitting somewhere nearby in a "tab" or "substrate layer of osmocote". The roots drink what has become water soluble via osmosis. This is basic biology. Roots are never "eating" dry ferts. They are always "drinking" water, which may or may not have nutrients in it. This is true for root feeding as well as foliar feeding. If you sprinkle dry fert dust on a plant's leaves, it won't be able to consume it. Likewise, if you were able to plant a hibiscus in a pot, and somehow were able to get some dry ferts in the soil, directly ON the half of the roots, but then when you watered, you were able to keep those roots dry, then the plant would not get any nutrients. The only way that hibiscus will benefit from that dry fert in its soil is if that dry fert gets wet, so the roots can drink it. Likewise, a root tab only benefits an aqautic plant by disolving into the water in order to be consumed. Again, this is why hydroponics are so amazing. Roots don't really NEED dirt. They only need it in natural arrangements to keep them upright, to protect against adverse conditions, etc. The soil itself provides exactly 0 benefit. The fungus in the soil? The bacteria? The ferts? All useful. The dirt? Not so much.




The fact that I am pointing out that your test does not confirm your hypothesis is purely a scientific standpoint. Again, I agree 100% with the conclusion. _*If already dosing ample ferts to the column, root tabs are superfluous and redundant at best, and potentially harmful at worst (overdosing). *_ 





Are you claiming that it is purely impossible that, if you split the tanks up, that the result could be different than if you kept them together? That's bad science, my friend. And you didn't prove it. That's the key point.



EDIT ADD: Another worthwhile test in this saga would be 2 tanks, NO dry ferts being dosed. One tank have root tabs in the substrate beneath the plants, and another one just drop the darned things directly into the water. Let 'em sit on top of the substrate. I'd hypothesize that both tanks would turn out nearly identical.


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## HaeSuse

Final Thought (for now):


No ferts at all.
Tabs on top of substrate
Tabs in substrate
Tabs in and on substrate
Tabs on top of substrate + EI
Tabs in substrate + EI
Tabs in and on substrate + EI
EI only

I'd bet the farm on Tanks 2-8 looking nearly identical after several weeks, and Tank 1 looking stunted. Again, using only the easy plants you've got mentioned, BDBS, no CO2, yadayadayada.


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## Patriot

All hail the crypts!


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## houseofcards

HaeSuse said:


> Negative.
> 
> Your conclusion includes (though maybe you missed it) ...


In your haste to discredit the experiment, you seemed to be confusing me with the person that actually conducted it. The experiment is reassuring to me and helpful to others who might be confused about whether they 'really' need root tabs to grow plants or not. Good luck doing laboratory-grade experiments that will be applicable to the hobby, but if it's that important to you why don't you start with your suggestion below of the way the experiment should have been done. 



HaeSuse said:


> Really, the best way to go would be 4 identical tanks, with the only delta between them being:
> tank 1 has no ferts at all
> tank 2 has just root tabs
> tank 3 has just water column ferts
> tank 4 has both root tabs and water column ferts
> 
> [*]No ferts at all.
> [*]Tabs on top of substrate
> [*]Tabs in substrate
> [*]Tabs in and on substrate
> [*]Tabs on top of substrate + EI
> [*]Tabs in substrate + EI
> [*]Tabs in and on substrate + EI
> [*]EI only
> 
> *I'd bet the farm on Tanks 2-8 looking nearly identical after several weeks, and Tank 1 looking stunted.* Again, using only the easy plants you've got mentioned, BDBS, no CO2, yadayadayada.


 Love the very scientific insight on tanks 2-8. 

Please make sure everything is done above board. I'll be looking for your "irrefutable evidence" results both in written detail and pictures of the entire process along the way. 

I'd bet the farm I never see it.


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## longgonedaddy

houseofcards said:


> In your haste to discredit the experiment, you seemed to be confusing me with the person that actually conducted it. The experiment is reassuring to me and helpful to others who might be confused about whether they 'really' need root tabs to grow plants or not. Good luck doing laboratory-grade experiments that will be applicable to the hobby, but if it's that important to you why don't you start with your suggestion below of the way the experiment should have been done.
> 
> Love the very scientific insight on tanks 2-8.
> 
> Please make sure everything is done above board. I'll be looking for your "irrefutable evidence" results both in written detail and pictures of the entire process along the way.
> 
> I'd bet the farm I never see it.



You forgot the need to use hundreds of individuals of many different species to avoid making conclusions from too small of a sample. So maybe a lot more than 8 tanks. :wink2:

In case it doesn't sound like it, I'm with you houseofcards, this little experiment was quite eye-opening.


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## houseofcards

longgonedaddy said:


> You forgot the need to use hundreds of individuals of many different species to avoid making conclusions from too small of a sample. So maybe a lot more than 8 tanks. :wink2:
> 
> In case it doesn't sound like it, I'm with you houseofcards, this little experiment was quite eye-opening.


Excellent point!

We should also have one with fish and one without, because you never know what magical ferts come out of the rear-end of a fish. Oh maybe one with different species of fish, since the concentration of magical ferts might be different in each one, so yeah. 
:grin2:


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## Nlewis

I'm absolutely loving this thread, thanks.


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## Patriot

Still giving my plants root tabs


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## longgonedaddy

houseofcards said:


> Excellent point!
> 
> We should also have one with fish and one without, because you never know what magical ferts come out of the rear-end of a fish. Oh maybe one with different species of fish, since the concentration of magical ferts might be different in each one, so yeah.
> :grin2:


Don't forget the food going into those fish. And what about same species from different, isolated populations? Or even more simply, wild vs farmed. Lots and lots of variables. :nerd:


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## LRJ

houseofcards said:


> Excellent point!
> 
> We should also have one with fish and one without, because you never know what magical ferts come out of the rear-end of a fish. Oh maybe one with different species of fish, since the concentration of magical ferts might be different in each one, so yeah.
> :grin2:


The Duhem-Quine problem


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## irresistible

did anyone mix clay + nutrients with cement or plaster of paris(Gypsum) to make diy root tabs?


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