# 24 hour lighting?



## OverThinker (Nov 3, 2009)

I have a 1.5g temp tank holding about 5 medium sized plants. Would turning the lights off at night cause the plants to suffocate themselves? Would it be okay for me to leave the lights on so they can photosynthesize for a few days? Is it mandatory to let them have night-time reverse synthesis?


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## roznalos (Aug 18, 2008)

All I know is that you will have an algae pool within a few days when you leave the lights on.


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## OverThinker (Nov 3, 2009)

But will the small tank force the plants to use up all of their available oxygen? Since I am breaking down this tank in a few days wouldn't it be better to have oxygen than no algae?


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## airborne_r6 (May 2, 2008)

OverThinker said:


> I have a 1.5g temp tank holding about 5 medium sized plants. Would turning the lights off at night cause the plants to suffocate themselves? Would it be okay for me to leave the lights on so they can photosynthesize for a few days? Is it mandatory to let them have night-time reverse synthesis?





OverThinker said:


> But will the small tank force the plants to use up all of their available oxygen? Since I am breaking down this tank in a few days wouldn't it be better to have oxygen than no algae?


I am going to give you a very detailed explanation as soon as I double check one thing in botany tomorrow. For now, plants will never suffocate themselves, they will never use all of the available oxygen and the problem with letting algae get started on the plants and moving it to your bigger tank is the more serious problem here. What you are suggesting is a non-issue. Shut the lights off for 12 hours a day.


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## Raul-7 (Oct 17, 2003)

I would think plants need to a dark-period or 'rest period' to help recuperate from photosynthesizing during the day. You will notice some aquatic plants, most notably Rotala wallichii, will actually fold in their leaves after a certain duration of lighting.


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## genEus (Oct 10, 2009)

Raul-7 said:


> I would think plants need to a dark-period or 'rest period' to help recuperate from photosynthesizing during the day. You will notice some aquatic plants, most notably Rotala wallichii, will actually fold in their leaves after a certain duration of lighting.


Wow. Finally I found an explanation for that occurrence! Pretty much all my stem plants fold their leaves as it gets later in the night. I could never understand why. So, that means that I should just reduce my lighting period and they'll be just as happy??

/sorry for the hijack


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## OverThinker (Nov 3, 2009)

Yeah, I guess that makes sense. They emit oxygen in the day by sucking up CO2. But at night they suck up the oxygen and emit C02. So really the only problem with a small tank like this would be if I had fish in there. Makes sense. A lot of plants react to TOO much light...we all just need to learn how to get it "just right", and in every situation it is "to each his own". It's a good thing we all have different specs and circumstances or else this hobby would be super boring.


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## airborne_r6 (May 2, 2008)

Raul-7 said:


> I would think plants need to a dark-period or 'rest period' to help recuperate from photosynthesizing during the day. You will notice some aquatic plants, most notably Rotala wallichii, will actually fold in their leaves after a certain duration of lighting.


Actually there is little to no biological evidence to show that plants need a rest period like animals do. They will just keep photosynthesizing. There is no evidence that they need to take any break from photosythesis. If you look at some things grown in the artic areas that have 24 hour sunlight during the summer they will actually have more growth and can produce some very large fruits such as squash because they are producing energy and starches continually. The biggest harm that may come from 24 hour lighting is that the reproductive cycle of the plant, in particular flowering plants, may be affected as many reproductive cycles are triggered by the length of the photoperiod. 

It is undecided amongst environmental ecologists and botanists as to why some plants close at night. Some plants close when under water stress to help seal in the stomata and conserve water loss, but this is more likely during the day and is not photo dependent. Plants that do not do this, including aquatic plants, may close to conserve heat or to reduce cross section to minimize potential damage from wind or water currents but the actual reason is currently undecided.


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