Plants behaving badlly

[JDogg]

what causes stem plants to grow out instead of up?

the plants i am having this problem with are Ludwigia repens, Hygrophila polysperma and Wysteria

it happens in all three of my planted tanks too...

Tank #1 = 10 gallons, 30 watts of T8 light, EI dosing, DIY CO2 w/ excel
Tank #2 = 10 gallons, 2 20 watts PC screw-in u-shaped bulbs, EI dosing, Excel only
Tanks #3 = 75 gallon, 128 watts of T8 light, EI dosing, DIY CO2

in all three tanks the above mentioned plants are planted in the back of the tank, and background, with the intent that they will grow up to the light, but instead they grow towards the front of the tank and shade the low growing foreground plants...

what am i doing wrong and how can i get the to grow up?

more light?

less light?

 

[rich311k]

They are growing towards the light. The light just happens to be in the center of the tank. My stems tend to bend as well. I have not come up with a way to get them to cooperate. I guess if you hung the light over the tank higher, the stems would grow straighter since the light would not be centered in the middle.

 

[JDogg]

i would agree with you as far as the tank with the screw in bulbs, those are in the center of the tank. however the bulbs on the other two are more evenly spaced from back to front. infact on my 75 gallon the center 3-4 inches has not light :?

 

[Jchillin]

I have to agree. This is coming from the (gasp), terrestrial side of botany if you will. I watch terrestrials bending all the time basically following the path of the light. The indoor plants are always bending toward the light. Based on these observations (and not to mention the bending I used to get with my other bulbs), there is definitely a concentration of light in each of the tanks.

Problem is, without a spectrometer, you will not know where it is. Which direction is most common?

 

[JDogg]

Which direction is most common?

twords the front of the tank

 

[black hills tj]

Does the tank face a window at all?

 

[JDogg]

Does the tank face a window at all?

nope

 

[SparKy697]

I have a theory. I have seen this same behavior in my tanks especially with the L. Repens. In my theory the plants are bending due to side shoots that sprout. The stem seems to bend to allow light to get to these new leaves.

Mine do this while growing directly below 260 watts of cf in a 55 gallon tank. They almost appear to grow away from the light, then turn and head back toward the light.

 

[newfound77951]

Under high light, stem plants will start to grow horizontally if they "think" they are at the surface.....I would guess that is the case in Sparky's tank; I get sideways stem plants with 192 watts on a 55, so 260 would certainly do it.

Hygrophila polysperma naturally grows sideways, and up, and down, and in circles. it's a weed, it always tries to shade out anything and everything around it in it's neverending Quest To Take Over The World. Same probably goes for the wisteria, it's a pretty good weed, too.

I could never manage to get my polysperma, repens or Myrio to grow straight up. They just won't. Some plants that I have that do grow up (most of the time, anyway) are Bacopa (caroliniana and australis) and Limnophila aromatica.

 

[DrizzleWizzle]

At what height are your plants growing laterally? On my tank, once they get to the top, my stem plants bend inward and forward. This is because (1) the back corners of the tank don't receive much light, and (2) they've hit the surface, and have nowhere else to go but out. So, in my case, I think that more light -- and more trimming -- would help vertical growth.

On the other hand, if your entire tank receives really good coverage, I would think that reducing light would help. Logically, I would think that once a plant gets enough light at a particular depth, it would begin to grow laterally instead of vertically, in an attempt to maximize surface area receiving light. (As Newfound mentioned, the plant would be receiving so much light that it "thinks" it is at the water surface.) Is it possible that your plants are receiving so much light that they've just given up any attempts to grow toward it, and instead have decided to just get as much of it as they can?

For example, it strikes me that there's a certain foreground plant which, under low light, will grow up, trying to get more light. Under high light, however, it grows out and create a carpet. (Can anybody name the plant I'm thinking of?)

However, now that I've thrown this theory out there, I don't know what would be the most effective way of reducing light. Fewer bulbs? Less intensity? Shorter photoperiod?

 

[hashbaz]

My theory is that you have too much light. Plant compete for light. When they don't have enough light they grow taller trying to get above the other plants or closer to the surface in order to get more light. If they have plenty of light then they start to grow horizontally in order to spread out and cover more area. I have wisteria growing as a ground-cover due to relatively high light.

 

[zenkatydid]

i agree with hashbaz. if a plant gets to a certain height and then bends, i would think that it has reached the maximum amount of light that it desires. after that, it will try and spread laterally. if you lower the light, it will grow vertical for longer, i would imagine.

 

[newfound77951]

For example, it strikes me that there's a certain foreground plant which, under low light, will grow up, trying to get more light. Under high light, however, it grows out and create a carpet. (Can anybody name the plant I'm thinking of?)

Hemianthus micranthemoides (pearlweed)....I have a great carpet of it under 4 wpg.

 

[AshleyXavier]

For example, it strikes me that there's a certain foreground plant which, under low light, will grow up, trying to get more light. Under high light, however, it grows out and create a carpet. (Can anybody name the plant I'm thinking of?)

there are several plants that behave this way:

cryptocorybe parva - long leaves that spreads open under high light, almost vertically up in low light

glossostigma - will grow up and not spread unless under high light