I'm having a hard time growing Ludwigia arcuata "fast". Whereas a healthy 10cm stalk of R. rotundifolia reaches the top in about 3 weeks a comparable arcuata stem needs about 2,5 to 3 times longer under the same irradiance and fertilizer amounts (including CO2 mist). Is this normal or may I have a slow growing species? Does the arcuata need "special treatment" to get a spurt? Or is this what I'm observing simply the difference in light demand? Tank is running on round about 2w/g.

Thanks very much,
Detlef

Under higher light, about 2x, I grew this one really fast, but biomass is bushy, not so much vertical. I had hard water(KH12, GH24), good CO2, standard plain old EI dosing

I had it as a main plant for 3 years in several tanks.
It has a different growth pattern than R rount.......

Submersed it gets bushier and more roots, tangles almost.
2-3x slower vertical growth is likely about right.
Top the R rount and wait for the L acurata to catch up.


Regards,
Tom Barr

Thanks Tom,

yes I can see how bushier growth patterns impact the speed of vertical growth.
Anyhow, when I look at some Arcuata shots around the net I really can get jealous wondering how that could be achieved.

Arcuata has its leaves 1,5 hrs longer unfolded vs. R. rotundifolia (13,5hrs vs. 12hrs) and supposedly needs both higher lighting and longer light periods to grow to its full glory.

Best regards,
Detlef

Well, here's the the tank I did:



I hacked it back aggressively 4x a month, about 50% each time.
So it had a doubling of bass every 2 weeks.

Just flourite, rock hard water, CO2, normal EI dosing, no GH obviously, TMG etc.



I can get the plant to turn green or redder with NO3.



I have several 35mm slide pics that are real nice, but have not been able to scan them well.

Maybe it is lighting..........

Regards,
Tom Barr

Well, I know you like playing the bass...


May be the Arcuata does not get sufficient light where it is growing in my tank or may be it's the water. I'm at 15ppm Ca and 3ppm Mg which is pretty low, likely a little low for this plant. I'm definately not observing the kind of strong growth you're presenting here.

I'm gonna try to find out what is wrong.


Best regards and thanks for replying,
Detlef

I think lighting might help.
I've not really tried to grow it under the same conditions in my softer water here, I have a A reineckii project at the moment

I did well with a Gh of 9 and KH of 5.5.

"Bass" and what was meant to read "mass", well, Freudian slip I suppose
Guilty as charged

Regards,
Tom Barr

That is one fiery bush of arcuata! Now I'm really jealous! How did you do that? Plenty of wpg lighting? I've 2x55wPL on 36x18x16in tank and I can't get my arcuata to get that red, worse I can't grow them standing upright, they're bending everywhere. Any tips? Thanks!

The growth pattern is odd with the plant.
It' does go all over, you just have to grow it fast and trim it(topping etc).

But.............I just yanked this up, then hacked the ratty bottom's off.
To get this look, I simply allowed the bush in the rear to double it's present trimmed size. So let it grow out more, then trim.

Then I went with full dosing minus NO3.
After 1 week, I trimmed and chose only the reddest stems to replant.

Just some simple trimming methods can yeild crazy red color.
Many seem to think that their plants show always look a certain redness.
Well, some parts will but often not the entire bunch.


But this is horticulture..........
I'd say the plant is similar in terms of growth as Rotala "Green".
It responds well to topping or replanting tops.

I used 110w on a 25 Gallon tank here.
Pretty high light for these days and crazy high light back then.

Folks suggested that open lower biomass tanks would get algae if you used EI.
Some suggested also that I could not do simple arrangements.
Clearly not.

This tank took a few weeks to do, then I moved on having made the point.

Regards,
Tom Barr

Provided I read the plants right I'd say both high light and N-stress can turn red plants even redder.
Low NO3 though is much more effective than high light. But it's the combo what you want to focus on in terms of
maximum red coloration.

IME Arcuata needs more than 2 watts per gallon and low NO3 levels (1-2ppm) to turn an intense red. The downside is if you let NO3
drop too low or let it bottom out for too long a time you'll easily stunt the plant. Daily fertilization with very small NO3 amounts AND a
higher fish loading for continous NH4 supply seems to be the best long-term approach. For short term purposes I suggest keeping the
plant at higher NO3 levels and to stop adding NO3 for some days like Tom did.

Now here is some speculation on the bending issue:

Arcuata tends to grow more upright
1. if it senses strong light from above
2. if fertilizer amounts are kept very stable (varying nutrients -probably changes in temps and other parameters as well- produces more side shoots)
3. if light with kelvin ratings below 10.000K is used


Best regards,
Detlef

Yep, pretty good summary.

Also, light needs only to be intense for a relatively brief period, say 2-4 hours a day.
But 10- works too

Regards,
Tom Barr