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Effects of too little light

Jaap

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30 Sep 2011
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Hello

I was wondering what symptoms would one see if the light in your planted aquarium is too little?

Thanks
 
If CO2 is the main 'building block' for plant growth and repair, and light is the energy source for this; surely the symptoms would be the same- poor growth, melting...

Despite saying this, CO2 is the most difficult to get right. And since the availability of T5s and LEDs it's all too easy to have too much light.
 
If CO2 is the main 'building block' for plant growth and repair, and light is the energy source for this; surely the symptoms would be the same- poor growth, melting...

Despite saying this, CO2 is the most difficult to get right. And since the availability of T5s and LEDs it's all too easy to have too much light.
Plants can grow with the minimal amount of CO2 e.g what's in the water. Obviously different plants have different requirements so yes, you see similar results but not as severe... You wont get transparent leaves, yellow maybe, which leads to rot, which leads to death.
 
One thing I've noticed lately is that poor light make much more difficult a bushy shape in your plants... But I guess the problem is that talking about low light or high light means really nothing. Light is just one part of the equation and good growth can be achieved with different combinations.

Jordi
 
So is there a chance that low light might have the same effects as in a situation of high light and low CO2 or bad distribution?
 
Hello mate. I understand how you feel at the moment, I was there once. I promise you if you keep at it, you'll get there eventually. You certainly have a good idea of what you're doing, just keep doing it and those god damn plants will grow eventually!

Please let me know your progress!
 
Thanks man very nice articles! One question....how do I know that I am not at or below the light compensation point? Any signs e.g no growth or little growth or melting or no sustainability?

I often wondered this as well in my low tech affairs.
I began to look at one or two plants, and noted the frequency with which new leaves appeared and so long as the new growth leaves looked healthy, then ...
I would actually count the numbers of new leaves on the majority of the plants (over weeks) and so long as new ones were sprouting then I assumed the conditions were at least acceptable for continued growth.
 
Ok I know that this has never happened before for someone to have lower light than the required because most of us just go crazy when it comes to lights.....but maybe my plants are melting because of poor light conditions...I mean my pH drops from an 8 to 6.5 and I have a kH of 9....I know my plants are the best indicators but isn't there a chance that my lighting is too little? Come on guys....its not always CO2 the problem....
 
Hi all,
I began to look at one or two plants, and noted the frequency with which new leaves appeared and so long as the new growth leaves looked healthy, then ...
I would actually count the numbers of new leaves on the majority of the plants (over weeks) and so long as new ones were sprouting then I assumed the conditions were at least acceptable for continued growth.
I think that is a pretty good approach.
Ok I know that this has never happened before for someone to have lower light than the required
It does, a lot of non-specialized planted aquarium keepers told me that they can't keep plants and they lose them in the winter. Often they said they could grow Java fern, but everything else died. I'm pretty sure this is attributable to lower ambient light levels in the winter tipping their plants over the edge.

The LCP of plants wil vary over an order of magnitude, if you have light intensity issues slow growing plants with dark green leaves (Bolbitis heudelotii, Anubias, Microsorum & mosses) are the ones least likely to show symptoms.

If you use EI you can tell whether it is a light or a CO2 problem by using a floating plant, they have access to aerial CO2 and this takes CO2 out of the equation. It is also recieving the full intensity of the lights.

I choose to use Limnobium laevigatum as my floater for the "Duckweed Index" as it has leaves without hairs etc., that might obscure the leaf colour, and it is more tolerant of low pH/low nutrients than the original Duckweed (Lemna minor).

cheers Darrel
 
Hi all,
I think that is a pretty good approach. It does, a lot of non-specialized planted aquarium keepers told me that they can't keep plants and they lose them in the winter. Often they said they could grow Java fern, but everything else died. I'm pretty sure this is attributable to lower ambient light levels in the winter tipping their plants over the edge.

The LCP of plants wil vary over an order of magnitude, if you have light intensity issues slow growing plants with dark green leaves (Bolbitis heudelotii, Anubias, Microsorum & mosses) are the ones least likely to show symptoms.

If you use EI you can tell whether it is a light or a CO2 problem by using a floating plant, they have access to aerial CO2 and this takes CO2 out of the equation. It is also recieving the full intensity of the lights.

I choose to use Limnobium laevigatum as my floater for the "Duckweed Index" as it has leaves without hairs etc., that might obscure the leaf colour, and it is more tolerant of low pH/low nutrients than the original Duckweed (Lemna minor).

cheers Darrel
What will you see on the floating plants that will indicate low light?
 
It will be less likely to have an algae bloom after a water change if something goes wrong. :)
Anyway feel free to experiment but any change you do stick on it for a couple of days to see results.
 
Hi all,
What will you see on the floating plants that will indicate low light?
Leaf death occurring more quickly than leaf growth, pale colour and a dwindling of the leaf rosette, this is known as <"Etiolation">.

At that point you've discounted CO2 (plant has access to atmospheric CO2 at 400ppm) and nutrients (via EI), so that only leaves light.

If the light intensity (really <"PAR">) doesn't reach <"light compensation point">, increasing the length of the photoperiod won't help, but increasing the PAR will.

If light intensity exceeds LCP, and nutrients, including carbon, are available the plant will show a pretty rapid greening, followed by growth, response.

The situation in a tropical water course would be slightly different from the situation in more temperate latitudes. In the tropics light intensity is very high, and a floating plant would need to be able to deal with very high light levels. Again this is why Amazon Frogbit is useful for the "Duckweed Index", it can grow quite happily over a large range of light intensities without showing light damage (although leaf colour may change and the red marking become more pronounced).

Here is Amazon Frogbit enjoying itself as an "invasive alien" in S. California (from <http://plants.ifas.ufl.edu/node/740>).

limlae1.jpg


Why plants scorch
Plants have evolved in differing environments, and a very dark green plant like Anubias spp. or Bolbitis heudelotii, will have evolved in a shady, low light environment. The plant is very dark green because it has a lot of chlorophyll to harvest as many of the scarce passing photons as it can. Producing chlorophyll has a "cost" to the plant, and natural selection via "survival of the fittest" will winnow out those plants carrying genes that produce sub-optimal amounts of chlorophyll (either too much or too little) for the conditions the plant evolved in.

If you place a very dark green plant into intense light for any extended period, Clive's <"photon torpedoes"> will damage them.

Why tropical plants are different

Tropical plants forest plants differ from those from more temperate latitudes in the way recieve the PAR they require. Rather than having continual diffuse light they will get in frequent ephemeral patches of very high intensity light, and areas that don't get any sun-light won't have any vegetation (not enough PAR).

lightpatch1.jpg


An end result of this is that a plant like an Anubias can adapt to higher light, when it has grown emersed with access to aerial CO2.

This is one of mine that has become emersed, the scorch marks are thermal damage from the leaves being in contact with the light unit (when it had spiral CFL lamps rather than LEDs).

lid_up_zpsf2edd702.jpg


cheers Darrel
 

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I would like to inform everyone that is interested in this thread that the problem was indeed too little light. The effects are not completely similar but are very very close.

If someone has low co2 then you see melting and plenty of it but as soon as you up the co2 all is fine.

If someone has too little light then you see no growth and very little melting as well as pale plants or dark leaved plants due to the high amounts of chlorophyll they produce to utilise the very little light given to them.

The effects are similar and can be mixed up but I believe someone with more experience than I have could have caught that earlier and easier than I did.
 
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