# Making stem plants grow bushier?



## awrieger (May 12, 2005)

And swords grow more compact?

Some of you may have been following my thread in the photo album about about my new planted tank, and so have seen my stem plants are growing long and tall with lots of stem between each leaf node. Makes them look spindly and thin. And they're not branching at all either. Just the one stalk growing straight up.

Same with the swords. Instead of being compact 'rosettes', the leaves are growing on long stems.

pH - 7
CO2 - 27ppm
light - 3.5 watts/gal

Can I make them all grow more compact/bushier by cutting back on the CO2 (to about 15ppm) as I'm planning to do? I thought I'd better ask and check first! I've already cut the light back in half to a single 55w tube so can't reduce that any further.

I'm just guessing it's the CO2 making them grow tall and fast and spindly instead of short and bushy, as the same Sessiliflora and Hygro and Aromatica in my non-CO2 tank with 3 watts/gal is growing a lot slower but it's thick and bushy and branching a lot (which is the way I want it).


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## scolley (Apr 4, 2004)

I really wish I had an experience based answer to your question. I don't. But I've been trying to pay close attention to the same issues for the last year or so, and have come to the following general conclusions:

1) Trimming is it's own art. Different plants respond differently. And to ask about how to make a given plant more bushy is a plant specific question, as far as trimming practice is concerned.

2) As a general rule, plants will grow lower and more compact, in higher light. They don't have to grow to get to better light. It's coming to them.

3) Light coloration plays a major role. While very, very high light in the 10K range seems to be a solid way of getting bushier growth, the amount of red, at any light level, seems to be a major factor too. Apparently near red (70 nanometers?), when in abundance vs. far red (760 nanometers?) seems to play a role in creating bushier growth.

4) Finally, and I'm less sure about this - nitrates may play a role. As with the general feeling that reds become more pronounced in low nitrate tanks, bushier growth may also accompany this. But I'm really unsure about this one.

I'm really looking forward to the responses on this, as I'm just as interested in understanding this issue.


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## Troy McClure (Feb 22, 2004)

This has always been a problem for me, so let's get to the bottom of it!


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## lumpyfunk (Dec 22, 2004)

I have heard that it is really, really high light levels that get the results that you want.


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## Robert H (Apr 3, 2003)

I really depends on what sword specie it is. There are many varieties of Echinodorus, and most do NOt grow compact, but grow to be quite large. There are a few dwarf species. Many swords have leaf stems. Nothing you can do about that, it is how the plant grows. Now if you are talking about runners with baby plants,, that is how the plant reproduces. A fully mature common Amazon sword is over 20 inches tall, 30 to 40 leaves and takes up about a third of a 55 gallon tank. Many swords will out grow a typical tank within a year. Swords with round or oval leaves have stems for lack of a better word, such as Melon swords, Ozelot, Oriental... and none of these are dwarf or compact species. I had a Oriental sword that took up almost half a 100 gallon tank.

Smaller species are E. horizontilas, E. parviflorus var tropica, E schuelteri var leopard, E. compacta, (which can still get up to 20"), and then the smallest of all are the grass like species.


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## BiscuitSlayer (Apr 1, 2005)

I have tried growing plants 2 seperate times with different results each time. The first time I tried it (when I had no knowledge), I used the stock 20W bulb that came with the hood on my aquarium. One plant managed to survive in my 29Gal tank: Moneywort. Eventually even my Moneywort died off. Last year, I upgraded my lighting to a dual 65W PC light. I again tried Moneywort, but this time it grew differently for me. It still grows fast and tall, but it also sends out plantlets off of the stem close to the base. Also, the leaves are closer together then what they used to be. There are other factors that I have left out like dosing micros and macros, which I wasn't doing before. 

My overall experience has been that with this particular species of plant, it will grow differently depending on its environment. My initial guess is that the lighting had the most drastic impact on the way that the Moneywort is growing for me now (bushier IMO).


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## awrieger (May 12, 2005)

Higher light equalling bushier growth makes logical sense, because that's what we expect with terrestrial plants - shaded plants grow more taller and thinner, trying to reach for the light.

But the exact reverse appears to be true with my aquatic plants though. Or at any rate, it's not the light at all, but the CO2 levels. 

Here I can make a direct comparison between cuttings from the exact same original Sessiliflora plant. Some in a high light / high CO2 tank, the other in a non CO2 tank. Compare:










Whether the light in the high CO2 tank (left) was 7w/g or reduced to 3.5w/g made no real difference to the stem distance between leaf nodes, which is on average about 5 to 6cm. The stronger light simply made the growth faster, with no difference to the actual growth pattern - long non-branching stems.

In the other tank (right), you can see a totally different growth pattern to a cutting taken form the identical plant. With what can be considered high light at 3w/g, the growth is far bushier, the spread of the leaves is greater and the stem distance between leaf nodes is less than 1cm. And there's a small branch developing. Overall speed of growth is far slower too.

Apart from just 0.5w/g difference in light and the (non)presence of CO2, all other factors except NO3 can be considered equal (the NO3 is actually lower in the more stemmy growth tank, Scolley). 

My conclusion is it must be the CO2 which promotes growth speed which translates as stem growth. So high light does indeed promote bushier plants, but not with high Co2.

Robert H, I also have two Marble Queen swords as examples too, taken from runners from the same parent plant. One is in the same high CO2 27ppm, 3.5w/g light tank has a stem of approx 16cm before the leaf actually begins. The other plant of equal size in another tank also with CO2, but only half as much at 12ppm, and 3w/g light has a maximum stem length of 8cm on all its same sized leaves. Literally, half the CO2 is producing half as long stems.

These are just my own personal observations.


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## scolley (Apr 4, 2004)

awrieger - these are some great observations. But I must ask, were the lights themselves identical? Your seem to be making a conclusion that the major differing factor was CO2, and that might well make the difference.

But light color is definitely implicated in this question. For more information on this topic, read this thread. In that thread you will also see that nitrate deficiency is also implicated in the "bushiness" issue.

I think at the end of the day you will find there are a lot more differences between those two tanks than just CO2.


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## awrieger (May 12, 2005)

Thanks for the link, Scolley. Never occured to me to search for 'internodes'! 

I had a quick scan and will read it through properly a bit later. Lots of posts! I got up to page three where Shalu writes "hm.. perhaps NO CO2 is the key"..

Anyway, I'm in Australia. Which basically means I can only get one type of CF plant-suitable spectrum bulb here. All three tanks have 6500/10000K tubes from the same manufacturer. So I can safely say the differing spectrum theory mentioned there doesn't apply because my setups all have the identical spectrum.

The only significant difference in my setups is the CO2 (and by inference, KH also as the CO2 tanks have higher KH).


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## scolley (Apr 4, 2004)

Well, that means we can toss out the light spectrum. That's great.

But what about the Nitrates? What's the difference in the two tanks? I'll wager the lower light, shorter internode tank has much lower Nitrates.


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## Troy McClure (Feb 22, 2004)

-NO- CO2?? Isn't that going to cause algae-havok? Granted, I've never had BBA, and I'm all for lowering it if that will result in short internodes, but no CO2 sounds like asking for trouble.

Regardless, I'll lower my CO2 to 15ppm and test if that helps over the next couple weeks.


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## Biznatch (Mar 26, 2005)

I was having the same problem with my cambomba where the noads were almost 1 to 1 1/2" apart. And I have 260watts over my 72 (3.6wpg). I just let it grow till it hit the surface where they nodes got much more compact and bushy the higher it got. Then after a few days I chopped off the bottom half (there were still roots coming out that could be planted) and planted it again. Now it seems to be growing much closer together. It's still growing very quickly to.


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## scolley (Apr 4, 2004)

Troy, I think you are jumping the gun. IMO no one is suggesting any specific course of action here. We're just trying to bottom out the possible causes.

I wouldn't cut back on anything just yet.


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## Troy McClure (Feb 22, 2004)

I understand what you're saying, Steve. It's just a test...a very unscientific test.

In my 85gal that has no CO2 yet, the hygro internode length is much shorter than it was while growing out in my 10gal with CO2. I have transfered all of the L. repens from the 10g to 85g and will observe their growth. Hopefully they will be effected in the same way.


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## Robert H (Apr 3, 2003)

I thought we were talking about sword plants in this thread...now we are talking about stem plants? I find the comparison picture odd, and the notion of higher light getting leggy growth, and low light bushy growth odd. In ten years I have never found that to be the case. I have grown Cabomba, Lymnophila, and Myriophyllum under very bright light and high levels of C02 and still have bushy leaf growth without the wide spaces between the leaf nodes. For me it has always come down to pruning. If you keep re planting the original tops, the stems remain thicker, the leaf nodes bushy and close together. If you allow new growth from cut stems, the new growth will always have thinner stems, thinner leaves, and wider spaces between the leaves.



> Robert H, I also have two Marble Queen swords as examples too, taken from runners from the same parent plant. One is in the same high CO2 27ppm, 3.5w/g light tank has a stem of approx 16cm before the leaf actually begins. The other plant of equal size in another tank also with CO2, but only half as much at 12ppm, and 3w/g light has a maximum stem length of 8cm on all its same sized leaves. Literally, half the CO2 is producing half as long stems.


Thats because without the C02, growth is stunted. As the plant matures, the stem portion gets longer and the leaf bigger. Swords plants can however vary in shape under any conditions. They are not always uniformily the same. My monster oriental sword had huge oval shaped leaves, but the baby plants it produced had more elongated shaped leaves. Swords that are hybrids of two or more species can revert back to one of the parent plants in the next generation.


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## awrieger (May 12, 2005)

scolley said:


> But what about the Nitrates? What's the difference in the two tanks? I'll wager the lower light, shorter internode tank has much lower Nitrates.


I just tested both and it's the opposite. The short-internode plant tank is 10ppm NO3, while the long-internode tank is 5ppm. 

So maybe higher NO3 availability produces more bushier growth? Lower NO3 certainly isn't reducing the internode length!

But it's not definitive. Maybe it relates back to the high CO2 again. The long-internode tank may have less NO3 simply because they're using up more of it to fuel their faster, better growth due to the high CO2.



scolley said:


> Troy ~ I think you are jumping the gun. IMO no one is suggesting any specific course of action here. We're just trying to bottom out the possible causes.
> 
> I wouldn't cut back on anything just yet.


I will! That's what my test tank is for - to test and see what happens! 

As soon as I finish typing this post, I'm going to trim all the long stemmy growth back and reduce the CO2 back to 15ppm and see what happens. Algae-havok, here I come!




Robert H said:


> For me it has always come down to pruning. If you keep re planting the original tops, the stems remain thicker, the leaf nodes bushy and close together. If you allow new growth from cut stems, the new growth will always have thinner stems, thinner leaves, and wider spaces between the leaves.


Well, that's the exact opposite of what happened with me. The (top) cuttings of Sessiliflora for example which I planted were from a non-CO2 tank and were very bushy with very short internode length. 

You can see it here in the first pic the first day I put it under the 7 watts light and with CO2. it's still all nice and bushy (ditto the aromatica you can see there too). The second pic in that post is about a week later when I actually did the aquascape. The plants were already getting stemmy even by then.

And here is how it looked after about 2 weeks under that 7 watts of light and CO2 of 300ppm. Very looooonnng internode lengths. Rapid growth with the high CO2, but all stem!


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## Troy McClure (Feb 22, 2004)

Devil's advocate - How would NO3 have anything to do with bushier growth? The way I see it, it wouldn't matter if you had 5ppm or 15ppm, you still have nitrates available. Assuming this has a bearing on growth, is it the concentration of NO3 that would produce an effect or merely deficiency vs. availability?

I've gone ahead and lowered my CO2 to a range of 12-15ppm and will continue replanting the tops of my R. indica.


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## scolley (Apr 4, 2004)

Troy McClure said:


> How would NO3 have anything to do with bushier growth? The way I see it, it wouldn't matter if you had 5ppm or 15ppm, you still have nitrates available.


I don't know. Take a look at the thread I listed previously, and maybe ask Shalu. He brought it up originally I think... :wink:


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## Troy McClure (Feb 22, 2004)

Any updates here?


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## awrieger (May 12, 2005)

No joy here. I reduced Co2 from 30ppm to 15ppm and doubled the light from 3.5 back to over 7w/g and I'm still getting long internodes. Maybe I should have left the light alone as I said I was going to do... Well, it's just not making sense to me. Stronger light should mean bushier, less need for long stalks like with terrestrial plants, no?

Anyway, I replanted the Lymnophilia tips as Robert H suggested instead of just pruning, planting under the shade of Val surface leaves in one corner, as well as in direct light in the other corner in order to compare. But both are identical (so I assume more than enough light is still getting through the Val), with growth patterns the same as before - long single stems, 4-5cm internode length, no signs of branching (although it's probably still too early for that).

Meanwhile, the Lymnophilia over in the non-CO2 tank with 3w/g light and higher NO3 is growing even bushier and putting out more side-branches.

I'm perplexed. Is it more NO3 maybe then?

Or... just an afterthought: I'm dosing both tanks with Excel, so maybe it's a matter of cutting back total carbon, not just CO2, so the test tank's C is still too high. Maybe I should try CO2 down at around 5ppm.. But I'm afraid! Afraid of algae! How far dare I reduce it before algae starts ravaging the tank? :icon_roll

EDIT: Maybe I shouldn't have increased the light... just tested the NO3 and it's virtually zero! So it could be either a cause or effect. Either the lack of NO3 is causing the longer stems, or it's the other way around and they're already growing longer stems under the stronger light and need to suck up every last drop of NO3 to do so. Impossible to day. I'll try upping the NO3 dramatically and see what happens. I'm not exactly going about this scientifically!


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