# Lighting timing vs plant growth



## uklau (Sep 26, 2006)

Hi, I'm wondering if there is any differences between turning on & off the light at different timing. To simplify discussion, assuming that the lighting is turned on for 12 hours a day. Will turning on the light from 7AM-7PM yields different result from turning on the light from 10AM-10PM?


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## avijitsen (Oct 28, 2006)

Hi,

Ideally there should be no difference in whatever 12 hr timmings you choose as far as the plant growths are concerned, until and unless you have the tanks placed in a location where they do get sunlight too.


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## ruki (Jul 4, 2006)

I think it won't make a difference for most plants, especially those that come from close to the equator.

For plants coming from seasonal climates, I'm not so certain. Especially blooming bulbs that require a rest period during the winter. Could a sudden 12 hour time shift confuse them?


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## hoppycalif (Apr 7, 2005)

You didn't ask about how long the lights should be on, but, if you have more than 2 watts per gallon, anything longer than 8 hours a day is probably helping the algae more than the plants. I don't see why it would matter to the plants when, during the day, the lights are on, but it would probably not work if the lights were on only at night and the tank was not in a darkened room.


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## Laith (Sep 4, 2004)

My tanks at home (both planted and African cichlid) have the lights come on at around 15:00 or 16:00 and off at midnight. Never noticed a problem with the plants... or the fish.

The only reason I have them on this time schedule is so that I can enjoy them at night.


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## yxberia (Apr 19, 2005)

There is a difference as day to night. The major difference is the changes of surrounding temperature. Depends on place your live, night time is always cooler here. So, I would normally turn on those lights in the late evening so the nett-effect from heat is not that high.


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## uklau (Sep 26, 2006)

The reason why I'm asking is because I noticed that my tiger lotus is displaying some behaviour as if it is able to tell between day & night. Regardless of whether the light (&CO2) is on or off, I noticed that during:
a) day time (after around 7:30AM onwards) - all the leaves are in horizontal position (parallel to the substrate).
b) night time (after around 7:00PM onwards) - all the leaves are in vertical position (perpendicular to the substrate).

Although my tank is facing the windows, it is not getting any direct sunlight. The tiger lotus had been behaving this way since I first planted it about 4 months ago. The only thing I can think of is the plant has the capability to determine day from night, without being influence by the artificial lighting. Any thoughts?


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## yxberia (Apr 19, 2005)

Some species will move facing light source even though it is just a dim light. Green rotala will change their position facing closed curtain in my dark living room. I think Most light demanding plant will show this behavior including tonina sp. They are too photo-sensitive.


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