time of day

[Ocelaris]

There are vigorous debates about whether leaving the lights on or off is required.

The facts surrounding the confusion lies in the "light cycle" vs. "dark cycle" of photosynthesis.

The light cycle is the normal photosynthesis producing Oxygen from CO2.

The dark cycle is when the plant takes in Oxygen and outputs CO2, it's a little misleading, in that it doesn't necessarily require darkness, just that it happens without the presence of light.

I'm not enough of an expert to say that plants NEED a dark period, but the typical argument of plants needing a "rest" is too much of a personification of human requirements to plants to be a good arguement IMO.

If you really want to push it, 18 on, 6 off is probably the max I would do, as I'm not confident they don't need dark, and but regression to a somewhat natural cycle sounds most preferable to me. Though many people do grow plants with the lights on non-stop, I am not sure if orchids would be affected, but certainly some plants do not mind light all the time.

[Royal]

Originally Posted by Ocelaris

The dark cycle is when the plant takes in Oxygen and outputs CO2, it's a little misleading, in that it doesn't necessarily require darkness, just that it happens without the presence of light.

Isn't dark the absence of light?

[Ocelaris]

Originally Posted by RoyalOrchids

Isn't dark the absence of light?

Exactly! That was my point, that by calling the calvin cycle "dark" it was a misnomer, called wrong, incorrect, dubiously labeled, misleading etc...

people hear "dark" and they think obviously, dark no light... but that is wrong to think that. It's bypassing the truth which is more complicated than "light makes plants grow, dark lets them sleep" 3rd grade mentality...

But it's like atheism, it's not a rejection of god, it's a lack of requirement for god... the calvin cycle is not a rejection of light, it's a lack of requirement for light...