Changing day to night lighting times

[nhman]

So here's the current setting: over 250 orchids growing entirely under banks of T5 lights. I have been growing them in this area - completely without any additional sunlight for about 1 year now. I use an airconditioner to counter the temperature that the lights create.
Now the question - I'd like to run the lights during the cooler nights for the summer (and perhaps continue that way). There are several reasons for wanting to do this, including reducing the need to run the air conditioner as much during the summer months and take advantage of cheeper electric rates over the evening hours to the benefiting my working with the plants given my work schedules.
Should I just extend 1 day longer and do the switch over 1 day - WHAM - or slowly move the times around over a longer period of time (more work for me..... )
Any thoughts or evidence that one idea is better or worse than the other would be appreciated.
Thanks!

[Royal]

Are you talking about shortening or lengthening the day, or just swapping day to night and visa versa?

Running the lights at night and going dark during the day is a good idea for temp control. Just make sure that the grow space is dark during the daytime with the lights off. Not just "no good sunlight", I mean dark.

As far as the transition, just do it all at once. Plants growing outside frequently get days that are cloudy, dreary, or rainy, so going a day without light won't hurt them.

[nhman]

Thank you for the feedback.
Since this is a fully enclosed area in my basement designed with growing orchids indoors via artifical lights and devoid of any potential for any light except that which I provide (kinda makes one feel sorta God like.....) total and complete darkness is never a problem.
Only thing to see is if my electric bills get better with this change!

[Royal]

Sounds totally logical to me. Let us know how it works out. I wish we had basements in Texas.

[catwalker808]

I agree with Royal that an immediate switchover would work well ... with a couple of howevers.
To do an immediate changeover, you would either have to do a REALLY long day, or a REALLY long night. I would opt for the really long night for 2 reasons. It would save you a day of electricity and it would be less stressful on the plants & your AC than to have a really long hot day. The only drawback would be that you couldn't look at your plants during the extended night.

The other consideration would be the effect on day/night temperature differentials. Because you're in New Hampshire, I assume your basement is so well insulated that outside temps don't come into play. In your case, there should still be a suitable day/night temperature differential inside the basement because of the heat and cool generated by the on/off cycle of the lights.

Not having a suitable 10-15 degree day/night temp differential can really mess up many plants, as can constant day lengths throughout the year. Some plants that are very seasonal bloomers will only put out new growths and have difficulty blooming.

[nhman]

OK. So we are now into May.
I have done the Day to night switch and have kept the temp differential with the Day to night time conditions - hey, we're indoors, we can do virtually anything.
Plants are all doing well with plenty of blooms and sheaths.
In summery, there does NOT appear to be any bad things that have occured with the rather abrupt change over.
All is well in the orchid garden!
Thanks for all of your input and I hope that this supplies a small bit of extra knowledge/experience to some!

[Undergrounder]

Originally Posted by nhman

OK. So we are now into May.
I have done the Day to night switch and have kept the temp differential with the Day to night time conditions - hey, we're indoors, we can do virtually anything.
Plants are all doing well with plenty of blooms and sheaths.
In summery, there does NOT appear to be any bad things that have occured with the rather abrupt change over.
All is well in the orchid garden!
Thanks for all of your input and I hope that this supplies a small bit of extra knowledge/experience to some!

I also switched recently, mostly to give the plants extra heating at night from the lights, when it can get cold here in winter. Now i don't need to heat at all during winter.

So far the plants have not shown any obvious problems (they were switched gradually, 3 times, 4 hours at a time over about 2 weeks).

The only caveat i would include with the theory is that most orchids (the CAM types like Phalaenopsis and Cattleya) use the light/dark cycle to stimulate their respiration cycle, and do completely different processes during the day and at night.

And studies have shown that in the complete absence of light, orchids continue to cycle in a subdued kind of way.

Biologists liken the effect to Circadian rhythyms.

So if you suddenly swap the light/dark cycle, then the plant will be getting mixed messages for a while until it adapts. It will want to respire during the day and photosynthesis at night - obviously a problem because there's no light at night.

But if this is a problem, it's obviously not a major one, as nhman shows. Humans get jet-lag too, and we feel pretty bad for a few days, but we get over it.