What Causes Stem Rot?

[Homer_Simpson]

I just thought I would put this out there. One more than one occasion and in different substrates and even in tanks at full throttle(with re: to c02 30 ppm, EI fertilization, and adequate lighting), I have noticed stem rot. This is where, a plant(ambulia, Bacopa monnieri, Ludwiga Repens, Rotala Indica, etc.,) should form roots and root into the substrate, but instead of rooting the stem turns brown rots, causing the stemmed plant to dislodge from the substrate and float to the top. At first, I thought that this was more due to the substrate, but I found that it even happens with stem plants put in Aquasoil, but not to such a large extent as with other substrates.

Any thoughts on what gives rise to this and how to prevent it. Is there a specific nutrient deficiency that causes this phenomena and if so, what might that be? I know that compariing terrestrial plants with aquarium plants is like comparing apples and oranges. Sometimes with rooting terrestrial plants, the stems are soaked in a special liquid fert before planting to promote rooting and enhance nutrient uptake. Is it possible to create such a soak or dip for such stem plants to stimulate vigorous roots before planting into the substrate. Thanks

 

[scottward]

I would ***LOVE*** to know what causes this stem rot phenomenum that you speak of!! I too am having the exact same problem and am banging my head really hard against the wall trying to solve it!!!!

If somebody can tell me what causes this problem and how to solve it I'd be willing to pay a cash reward!!!!!!!!!!

Any ideas??????????

Scott.

 

[adechazal]

I've seen this question posted before and don't recall seeing any of the "big guns" reply. I too have experienced this when I cut the tops off of some plants and re-plant them and I have two theories that may occurr separately or be combined to cause the issue:
1. The stem is damaged during the cutting/replanting stage e.g. use sharp scissors (no pinching) to cut the stems of larger diameter stem plants and dont crush the stem when you re-plant the top.
2. Make sure the substrate isn't stagnant in the spot the new plant is placed. (aerate the substrate with fingers prior to planting)

Theories only, I have no cause-effect data to back this up.

Aaron

 

[Carissa]

I have heard that floating the plant and allowing it to develop roots on it's own, then planting it once there are roots there, will solve this problem.

 

[VaughnH]

What I have observed is that if the conditions are such that stem plants will grow rapidly, there is no stem rot. But, if anything is off so that they will not grow rapidly, you do get stem rot. Like all generalizations, this one breaks down for certain plants for certain people. Some stem plants refuse to grow for me no matter what I do. I solve that problem by growing other stem plants. Fortunately there are many, many to choose from.

 

[Grafalski]

I live close to Chicago and I started having problems with stem rot after mixing my tap water with RO - 50/50. I had trouble especially with Myriophyllum tuberculatum. Tom's advice was to add 1 tsp of MgSo4 to 500ML of TMG. So far so good.

 

[scottward]

Could it be related to macros, i.e. insufficient (or too much) nitrogen, phosphorous or potasium?

 

[Jamieman]

I have just started having this problem. Always in the same place in the tank & it always starts at the substrate, then works it's way up.
I think Carissa could be right on this one as the stems that rot have no roots at all.
I think lack of water circulation at substrate level could also contribute.
I will be trying a couple of things & will post back my results.

Jamie

 

[rthomas]

I've seen this question posted before and don't recall seeing any of the "big guns" reply.

Exactly Aaron. I hope them Big Guns don't keep mum over this issue. TIA.

 

[Tom Barr]

Here's the general idea behind what is referred to as "auto fragmentation".
Low nutrients, low CO2 particularly and low N, bad place to live.
Maybe current, maybe light etc, anyway, the plants break up in hopes of drifting away to a better place and regrowing, sort of like seed dispersal, but much faster and better to find new and better habitat.

Generally poor CO2, poor nutrients(easy to rule out light and nutrients).

Regards,
Tom Barr

 

[rthomas]

'Auto fragmentation' ahaha. Thank you Tom for theory. It sounds very logical to me.

 

[osnapitseric]

auto fragmentation is a interesting theory. Sort of like sea anemone. I had experience with rotting stem as well. I don't know the name of this plant but it's fairly common. Anyhow after planting it in my tank it grew fine. In fact it grew rather quickly. One day i noticed that the stem began rotting but the plant was growing healthy (or it seems). I don't know why it happened but long story short. I uprooted the tank and cut off the rotting stem and replanted the plant. The only thing i can think of was that the stems and roots of all bunched together which caused rotting (fighting for nutrients) so i placed them a bit further this time.

 

[scottward]

Did anybody ever figure this out?

 

[bsmith782]

I have noticed stem rot to occur on stems (mainly faster growers) because they get shaded near the bottom by new growth. L.repens x 'cant remember the cross plant' is horrible and so is d.diandra too.

The member above that said it happens after tipping/replanting makes sense as you are replanting the tools near the rooted stem effectively shading that rooted stem.

Some plants just do not like to be crowded. This is also true of syngonanthis Madeira and tonina 'narrow leaf' in my tanks. The stems have to be about one inch apart or after a week or so they will rot.

 

[nipat]

May be ferts in the water column makes stem plants careless?
There is food in the water, so why worry?

May be tanks with nutrient rich substrate but low in water discourage
stem plants to leave?

Just a quick thought.

 

[Paul G]

I have often wondered about this. Autofragmentation is a given, but doesn't necessarily explain why the plant didn't like that particular spot in the first place, especially after we took such great care to make it happy there. Sometimes we get survivors, often we get duds.

Perhaps after pruning, all the physiological pathways required by the plant to "communicate" biochemically with the soil are not present in the stem. Plants that survive are the ones that manage to break through this "boundary" and develop those pathways before adverse conditions set in. It's probably complicated beyond imagining, but I suspect oxygen plays a role. I have had most success starting stem cuttings by loosely surrounding them with course clean gravel in peat pots so that well aerated water can circulate around them. When roots start to bud at the nodes, the plant is home free.

 

[Matt F.]

Had this happen with ludwigia arcuata in aquasoil.
EI dose tank, T5HO, a lot of CO2, etc.

I've seen it happen in to situations:

1) established bush- bush too thick, light doesn't reach bottom.

2) newly planted stems- healthy growth up top, but stem rots out below. Usually root things comes from the nodes and anchor the plant to the substrate. What I do is cut the stem to healthy tissue, then remove one or two layers of leaves (from bottom). I do this and replant. So far the rot hasn't come back.

Gotta show the plant who is boss.

 

[herns]

Interesting topic.

I have the same problem with my smaller tank recently and still fixing it by changing lamp, careful dosing.

My previous set up of the same tank did not have this problem. Until I re-scape and change the light fixture.

 

[Tom Barr]

Milfoils (Myriophyllum species)do this quite a bit, those fast growing weeds commonly do this, it's a great way to travel and folks say plants cannot move ? Poppycock.
Hydrothrix does this and may produce turions, as may Elatine and a few others, these turions are small vegetative buds that are clonal forms of the mother plant.
Hydrilla does this as well as sinks down subterranean turions, which...are referred to as "tubers" commonly.

So aquatic weeds have:

Seeds(long term genetic variation), clonal parts/cuttings, autofragments, root crowns, turions, tubers.........all excellent for moving around and taking over, even if dry for a few years.
This is why they are really a problem environmentally.

Let's add some issues to this: aquatic plants have the lowest biomass to volume ratio: they do not need/require strong structural support due to water buoyancy. they also construct their stems and leaves in honey comb fashion, this requires MUCH less carbon/biomass and is rigid like a scaffold on a bridge.
This is also why they yield little nutrients to herbivores which really do not gain much from the plants, but the periphyton growing on them is rich however.There is also the problem of dewatering the weeds before feeding to say, cattle.

Weeds will melt due mostly to nutrients and CO2.
Sometimes lighting if the change is dramatic/strong.

 

[Forumsnow]

Weird you mention the elantine. It was growing like a gang buster for me and the the lower leaves just started melting. The roots are still super healthy looking and new growth looks good. I first thought it was no3 cause I heard it was a hog but to no avail. Then I weNt to co2 cause that is always it. But I have a nw blowing right on it and still it melted. It grew like crazy when I got it under worse conditions. Sure it is still co2, it's always co2.