# Do plants NEED a period of darkness at night?



## cgcaver (Jan 19, 2005)

I was just curious if plants really _need_ a period of darkness every night. I am up late at night many nights due to work/baby, and I enjoy watching my tank, so I'd really like the lights on ;(

Is indirect sunlight only (the room is not all that well lit in the daytime), with no lighting on the tank enough darkness to suffice?

I have timers on my lights, so, what would be a good light regimen for my tank? What length and hours should I run that would also allow me to enjoy my tank till about 4am at night? Is that even possibly while still being healthy for my tank?


P.S. I forgot to mention that I have the ability to run 1.75wpg, 2wpg, or combined for 3.75wpg. I dont remember the exact Kelvin rating, but one of the bulbs is on the "green" side of the scale, the other is more on the "red" side.


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## Lil boy blue (Jan 26, 2006)

No plants can have lights on 24/7 but fish can not, it will stress the fish out too much if the light is constantly on. But you might get an algae bloom....im not sure..


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## BlueRam (Sep 21, 2004)

Plants do not need darkness (or night). They grow when the see light and the "dark cycle" just indicates that the process occurs without light. Fish do get a little jumpy if lit 24/7 but I am currently lighting my angelfish grow out 24/7 so that the grow a little faster.

I set my timer to be on for 2 hours early (on when I leave the house) and then on from ~5:00 to 10:00 (when I am home).


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## rain- (Mar 29, 2004)

To answer your question:

http://plantanswers.tamu.edu/publications/houseplant/houseplant.html says:
"However, plants require some period of darkness to develop properly and thus should be illuminated for no more than 16 hours."

http://www.lowes.com/lowes/lkn?action=howTo&p=LawnGarden/houseplants.html says:
"Most plants do their growing at night, so make sure to provide a daily period of darkness."

But I don't know how scientific that belief is. Kasselmann says that maximum lighting time is about 15 hours. I wouldn't keep the lights on all the time if you want your plants to grow and your algae not. I would say that a few hours of darkness is a good thing. 

I often stay up late and I keep the lights on about 12 hours a day now, switching on at a bit after 1 PM and turning off a bit after 1 AM, sometimes I leave them on till 3 AM if I am staying up late. The plants seem to be OK with this type of lighting period.


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## koi-boi (Apr 29, 2006)

Hi,
Plants won't be hurt by 24 hour light, but after a point they don't benefit by it either, but algae will. Fish are more a concern and most will be stressed in 24 hour light. But "dark enough" is the real question. Your indirect light during the day is probably pretty dark in the water, so that might be dark enough. Or if you're not home during the day drape something across the front of the tank to provide dark so that you can light up the tank at night. Another alternative might be to put a few night lights or a string of led christmas lights in the canopy for very low light levels that still allow you to see the fish. You'd be observing night time behaviour, which might be cool! Again, depends on the types of fish. Hope that helps.


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## ringram (Jan 19, 2005)

Just a little word of advice...Are you planning on keeping the JDs and cories together long term? I can almost guarantee that the cories will become food once the JDs get bigger.


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## cgcaver (Jan 19, 2005)

duely noted


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