Stem Turn Black

[blue33]

Stem turn black. This is one of my rotala sp, few of the stem turn black. Could it be due to death spot? Anyone encounter, can tell me why? Below is the pictures of the stem plant turn black. I read somewhere before that it can be due to too much phosphate. Is it true? Thanks!

[Verminator]

Alot of the plants i ordered recently were like this due to 13 days in a black box in transit from singapore. I found snipping them off leaving the green part of the stem above this black spot and replanting them works fine. Throwing the left overs away. They've since regrown and are slowly getting bigger and bushier. These observations have come from my Ludwigia Repens and Gymnocoronis Spilanthoides.

As for the root cause, it could be multiple things. But from my experience it was from no light what so ever. If some more expereinced people want to give advice here please do...

[blue33]

Thanks Verminator! I find that it could be death spot, lack of lighting at that area etc... Few stalks having this problem, turn black and later it melt from that black part, above the black part the plant still growing, strange. Anyone having this issue for stem plant? Anyway to solve it? Or this is common problem for stem plant?

[blue33]

I did remember "koah fong" also having the same problem mention in his website on

1)"Rotala rotundifolia (indica) Bottom part sometimes blackish. Probably lack of light. But top part can seem to be growing well as it looked reddish",

2)"Rotala rotundifolia (indica) Grew black spots on the stems".

Currently some stalk of my Rotala having same issue. Maybe is the lighting problem! Probably is a common issue on stem plants. Anyone can verify?

[blue33]

Anyone knows?

[benetay]

Yes i believe you've answered to your question. The problem with stem plants is that they are always planted densely together. The black potion is where the plant couldn't recieve sufficient lighting. It didn't really die but grow towards a light spot for it to continue growing.

The first sign of light deficiency is when the leaves start to melt off turning brown. The top part of the plant might be thriving well in the high lighting it receive. So instead of channeling energy to produce more leaves in the bottom, the plant decides that channeling it's energy towards the top is more energy effective. That is also the reason why stem plants are normally planted at the back. It's got some cover in the front to cover it's bare stem.

Trim plants(stem) regularly to prevent that to happen or increase the light intensity.

These are my observations.
Maybe someone who have more in-depth knowledge might want to share with us.



Cheers!

[blue33]

Yes i believe you've answered to your question. The problem with stem plants is that they are always planted densely together. The black potion is where the plant couldn't recieve sufficient lighting. It didn't really die but grow towards a light spot for it to continue growing.

The first sign of light deficiency is when the leaves start to melt off turning brown. The top part of the plant might be thriving well in the high lighting it receive. So instead of channeling energy to produce more leaves in the bottom, the plant decides that channeling it's energy towards the top is more energy effective. That is also the reason why stem plants are normally planted at the back. It's got some cover in the front to cover it's bare stem.

Trim plants(stem) regularly to prevent that to happen or increase the light intensity.

These are my observations.
Maybe someone who have more in-depth knowledge might want to share with us.



Cheers!

Thanks Benetay, for clarifying the doubt i have. Thats why MH is still best for stem plant or any plant, the indensity that able to cast or penetrate to reach the plant base. I've come across Amano mention on the indensity. Amano quote, "Fluorescent bathe the entire aquarium in soft light all round, the directness of the lighting from metal halides can produce sharply defined shadows".

[benetay]

MH's intensity is really strong but i think T5HO is coming up near to it. Maybe in the near future there might be something to replace MH.

I've tried MH before they're very warm, maybe not so much to the water column but it can warm up the living room quite a bit. Stand 3 feet away from the tank & still you can feel the heat produced. Any insects that fly at night are attracted to the bright light but upon touching it, will send it straight down as fish food.

Cheers!

[blue33]

MH's intensity is really strong but i think T5HO is coming up near to it. Maybe in the near future there might be something to replace MH.

I've tried MH before they're very warm, maybe not so much to the water column but it can warm up the living room quite a bit. Stand 3 feet away from the tank & still you can feel the heat produced. Any insects that fly at night are attracted to the bright light but upon touching it, will send it straight down as fish food.

Cheers!

Currently i've 2ft 4XT5HO 24W for my 1.5ft cube, still some of rotala sp green having black portion, and you are right, light couldnt reach there as they are too dense and some of the plant appear black portion after quite a while and will melt off but amazingly the plant still survives. I guess when trimming, there's really need to control where you want it to be, somehow still will have black portion. Alot of time as what you said get something to cover the leggy leg, oh... and the black portion.

[torque6]

blue33,

I recalled you already have a greater than >5wpg, about 35w right for a 1FT, still having this problem ?

I plan to keep rotalas sp green in 6-9 weeks time with 18w 6500k Osram tube, and from the looks of your tank, i may have this problem as well. I was actually advise by alot of guys to keep it under 3wpg.

[blue33]

blue33,

I recalled you already have a greater than >5wpg, about 35w right for a 1FT, still having this problem ?

I plan to keep rotalas sp green in 6-9 weeks time with 18w 6500k Osram tube, and from the looks of your tank, i may have this problem as well. I was actually advise by alot of guys to keep it under 3wpg.

Is 1.5ft cube tank, today i just adjusted to 72W instead of 96W, T5HO, all this provided you have massive plant growth, initial stage 55W would be good for a 1.5ft tank and as it grow more dense and massive you can adjust to 72W, you need to check your current flow to all areas so as to distribute evenly to all plant.

If you want some rotala sp green, i can give you some to try.

The problem i've now is i've planted too pack together, other than that no problem, only problem with light passing to the base.

[torque6]

I was advised to plant the rotalas 2-3 inches apart, with a half way trim and consequentially 3/4 trimm to create a more compact growth. Of course to hide the leggy stem, will need some rock/driftwood to cover them up.

[blue33]

I was advised to plant the rotalas 2-3 inches apart, with a half way trim and consequentially 3/4 trimm to create a more compact growth. Of course to hide the leggy stem, will need some rock/driftwood to cover them up.

You can try it and let me know, but i think is too further away with each other.