# Ludwigia repens Stem Rot



## Sandman

Can anyone advise me on what could be causing the stems on my Ludwigia repens to rot? They are deteriorating near the base of the stem. Thanks.
Paul


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## hoppycalif

What size tank, what lighting, how long in the tank, what fertilizing???? Then it will be easier to figure out - maybe.


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## Sandman

My tank is a 90 gal with pressurized CO2 and 220 watts of light (2.66 WPG). I occasionaly add Excel, do twice-weekly doses of Flourish and also added some Flourish tabs to the substrate. I've had the Ludwigia a little less than 2 months. Have not started fertz yet. Have some on order from RG. Thanks


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## Emerc69

BUMP!

I have the same problem! i was just going to make a post on this(narrow leaf ludwigia tho). it has been haunting me for the last 2-3months. i dose exactly the same stuff minus the tabs. i do have flourish substrate tho. 

29g
using flourish excel and comprehensive plant supplement
2.25wpg for 10hr maybe 11 (when i get home i mess with it for about n hour)
CO2 is at around 20-30ppm (kh9 ph7)
temp 78-79F

i was thinking it could be an iron deficiency but the comprehensive plant supplement has iron in it.... does it need more? makes me want to use the complete seachem supplement set.

the weird thing is that every other plant is doing good HC, Riccia, some kinda tall grass, n my anubis nana.


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## hoppycalif

A robust growing plant like that Ludwigia needs a good supply of NPK or it wont do well at all. So, you can't grow it unless you fertilize it. And, when you have that much light all of the plants quickly strip all of the nutrients from the water, leaving them all only able to grow very slowly.


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## Emerc69

Thx hoppycalif i think ur right. what kinda of ferts would you recommend? i was thinking of buying the set at pfertz.com but is 60+shipping. where do u get urs?


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## hoppycalif

I dose the cheap way - I buy KNO3, KH2PO4 and CSM+B from http://www.aquariumfertilizer.com/, and dose them per the EI method.


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## scottward

I'm another one having this problem with H.Polysperma and Ambulia sessiofloa and H.Stricta!! I've been banging my head against the wall trying to solve this problem for month. I too have a 100% flourite substrate, am dosing Flourish twice weekly and Flourish Iron daily, 400 litre tank, 240 watts of light, CO2 injection to 30mg/L.

I can pick up a nitrate level with my test kits, so I didn't think I needed to macro fertilise?

Anyway, I've ordered some Seachem Nitrogen and Phosphorous. I'm going to give it a go.

How are you going Paul??

I'd be VERY keen to keep in touch with you on this one, as I too would LOVE to solve this rotting stem problem!!

It's frustrating!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Scott.


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## Sandman

Glad I'm not the only one having newbie problems...



> How are you going Paul??


Following the advice of several experienced plant people, I decided to go the dry fertilizer mix-your-own route and I ordered the fertilizers from www.bestaquariumregulator.com/ferts.html.

From what I've been told, the Seachem products are excellent and very convenient but also expensive... The dry fertilizers cost much less - especially over the long term. With dry ferts, there is a small initial investment for measurement and dosing equipment (such as an electronic scale, mixing containers, syringes for dosing, etc...) but the cost savings easily covers that.

Either route you take, there is still the bigger challenge of learning the proper dosing amounts...

Thanks Scott, I'll keep you posted on how things go...


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## Robert Hudson

LIGHT LIGHT LIGHT LIGHT. If the stems are rotting from the very bottom, not forming roots, its insufficient light. Stem plants, and particularly Ludwigia, are NOT low light plants. If you have close to three watts per gallon, how old are the bulbs? It may be time to replace them. How many hours a day do you leave the lights running? If its far below ten hours a day, you are in trouble. How crowded is the tank planted? If plants are too close together light can not reach the bottom of the stems.



> 400 litre tank, 240 watts of light


 Whats that in gallons? Do you have 240 watts of flourescent or incadescent? If you are using incadescent bulbs, you need 5 or 6 times MORE watts per gallon than flourescent. Anotherwords, 240 watts of fluorescent light is five times brighter than 240 watts of incadescent.

Let me put it another way, I grow Ludwigia repens under 3 watts per gallon, No C02 and No ferts at all for months, no NPK, no nothing. Just light. It grows like a weed.


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## scottward

The light is not the problem. I am 100% sure of this for the following reasons:

- I am using exactly the same type (i.e. same brand and model) of T8 flourescent tubes that I have been using for years. These tubes are NEC Biolux-HG tubes designed for aquarium plants.
- Several years ago, I only had HALF the number of tubes over the tank and the plants grew fine without rotting at all.
- My tubes are currently less than 12 months old and were, in fact, less than 6 months old when this problem started to occur.
- My lights are on for 14 hours per day.
- My stems are not crowded together. In fact I experimented by planting some individual stems out in the open to see if they would take root and grow properly; they rotted away!

Therefore it is neither the type, the amount, the duration nor the age of the tubes that is causing this problem.

I think it's 'something in the water', or, possibly, 'something NOT in the water'.

It will be interesting to see if dosing with the macros solves the problem or just causes lots of algae!

When do your ferts arrive Paul? ;-)

Scott.


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## terrestrial_man

Am wondering just how deep are the plants planted?
Reason is that this common aquatic species probably experiences changing levels of water in its
native habitat and maybe even periods of partial emersion. Most Ludwigias grow as mostly emersed plants upon muddy soils along slow running streams or in shallow areas of quiet bodies of water.
If you are experiencing rot and the plants are deeply rooted then perhaps adding an aristone near the plants may be helpful in generating some aeration near the stems and supplying the needed O2??
May a aeration strip?


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## Sandman

scottward said:


> When do your ferts arrive Paul?


I just got a message today that the ferts are in transit so I should have them in a few days. I bought RG's "Fertilizer combo pack" which includes the basic NPK ferts plus a traces & iron supplement.

I'm still in the process of aquiring some necessary equipment...particulary a scale. I arranged to purchase one from a member of our local aquatic plant group (GWAPA) at our next meeting in a few weeks. In the mean time, I'll just mix the ferts by volume instead of weight.

Terrestrial man, I think adding aeration might be counter productive to the CO2... I also have a reasonable amount of light in my setup so I think agree with Scott that the stem rot issue is more likely due to missing nutrient(s). I'm hoping that starting the ferts will solve the problem... We'll see what happens.


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## scottward

I've got some more ferts arriving later this week. I'll keep you posted too on how I go.

Scott.


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## Emerc69

im planning on going with the pfertz set and seachem iron. just waiting for my pay check to come in this week im also going to stop dosing excel for a lil bit to see if i hav any changes in the mean time.


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## Sandman

Great! Let's all keep each other posted and we can compare results...


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## scottward

I've started dosing the macros. 5mls of Flourish Nitrogen and Flourish Potasium on Monday and Friday. Still dosing Flourish and Potasium on Wednesday and Saturday, and 10mLs Iron every day.


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## Sandman

Let us know the results. I started daily doses of Flourish Iron and plan to start the macros this weekend as soon as I get a chance to read up on dosing amounts, etc...


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## hoppycalif

scottward said:


> I've started dosing the macros. 5mls of Flourish Nitrogen and Flourish Potasium on Monday and Friday. Still dosing Flourish and Potasium on Wednesday and Saturday, and 10mLs Iron every day.


You need phosphates too or the plants can't grow enough to use the other nutrients. If your tap water contains high phosphates you can use that, but you have to change water weekly or you still run out of phosphates.


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## scottward

Ah - my mistake - I typed Potasium when I meant to say Phosphorous! I dose the Potasium on Saturday and Wednesday, with the Flourish, and I am now dosing Nitrogen and Phosphorous on Monday and Friday. I dose Iron every day.

What's the best Phosphorous level to reach?


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## hoppycalif

scottward said:


> Ah - my mistake - I typed Potasium when I meant to say Phosphorous! I dose the Potasium on Saturday and Wednesday, with the Flourish, and I am now dosing Nitrogen and Phosphorous on Monday and Friday. I dose Iron every day.
> 
> What's the best Phosphorous level to reach?


The two basic fertilizing techniques are: use test kits and try to achieve a certain level of each fertilizer that way, or don't use test kits, and just dose per the manufacturers or other recommendations. I do the latter, per the estimative index method.

I started that method when I learned that testing had shown no adverse effects of several times the levels of ferts the method would result in. So, since I don't enjoy doing lots of testing, I switched to the EI method. With Flourish fertilizers you can follow Seachem's chart which tells you how much to dose, or you can double those dosages if you have high light and good CO2 concentration.


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## Sandman

Here's my update:
I received the dry ferts and mixed solutions using the amounts provided by RG except for K2SO4 which, as he recomends, I am dosing dry. I am using the estimative index method along with Chuck Gadd's Planted Aquairium Calculator to determine the dosing amounts based on his "Suggested Tank Target Level" amounts. 

Here is my planned schedule:

Day 1, 3, and 5: 50% Water Change, KN03 to 5ppm, K2SO4 to 20ppm, and Plantex

Day 2, 4, and 6: KH2PO4 to 1ppm

Day 7: nothing

Hoppy, does this look okay to you? Anything missing?
Thanks!
Paul


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## scottward

How are those plants looking? My Ambulia sessiflora is looking a lot better, still not perfect, but better. Hygro is not doing anything though. I just purchased the book 'Ecology of the Planted Aquarium' and I have been reading it (it's good). I wonder if Allelopathy is the cause of our plants rotting??


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## hoppycalif

scottward said:


> How are those plants looking? My Ambulia sessiflora is looking a lot better, still not perfect, but better. Hygro is not doing anything though. I just purchased the book 'Ecology of the Planted Aquarium' and I have been reading it (it's good). I wonder if Allelopathy is the cause of our plants rotting??


Allelopathy has not been found to exist in aquariums. So, that is not the problem. Almost all of our plant growing problems come down to fertilizing, light, CO2, water circulation and cleanliness. When we get those under control the plants grow well.


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## Sandman

scottward said:


> How are those plants looking?


Scott,
Still too early for me to tell if there is any improvement from the ferts. I ended up removing all of the Ludwigia because it was in pretty bad shape. The Hygro polysperma, Rotalia rotundifola, and Hygro corymbosa 'siamensis' are all growing well and my Anubias has flowered too. No noticable improvement on the crypts or Lobelia cardinalis though. I am still unsure about proper dosing amounts but I'm sure that is something I will learn with more experience and results... Good luck and keep me posted on your progress.
Paul


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