How many hours do I leave the Lights on..?
 

Now that I have (2) CFL fixtures with 6500k spiral bulbs in each fixture, I'm wondering how many hours do I keep the lights on ....?

I've been turning the lights on when I get up and leave them on all day .... depending on how I turn the fixtures I can get between 1500fc to 4000fc of light on my orchids.

I keep mine on for 12 hrs in winter and gradually ramp it up to 14 for summer. In late Sept. I'll gradually go back down to 12. Tindo is right though. Most tropical plants are from around the equator and experience 12 hrs. of daylight all year long.
By the way, put them on a timer. Then you don't have to worry about it.

Bill

I would second the timer idea for reasons of expedience as well as consistency. There are some orchids that don't appreciate any significant variance in their light cycles.
I typically run my lights 12 hours per day throughout the year.

For my tropicals (all seventy some odd of them), I keep the light somewhat similar to what's going on outside during the winter. There is one overhead light though that is not on a timer, and I turn it on and off by hand. That one I will turn on when I wake up, about 1 hour before "daylight" in the growing area and then I tend to leave it on for an hour or longer after "daylight" has stopped in the grow area. For me, this helps the plants that need more light. I kind of see it as the sunrise and sunset period where they are getting light, but just not as strong.

I have no scientific verification if I'm doing this right, it's just by feel and it has worked for years.

That being said, I only have a few orchids in my grow area. The rest of them are in windowsills throughout the house and get the light naturally. They all have done fine on the "natural light" schedule. Again, it depends what kinds you have as to what their needs are though.

I do the same thing. I have all of my lights on timers and I set them to turn on 1 hour before sunrise and 1 hour after sunset. This way the daylight period "adjusts" for the seasons. If the daylight period is going to be less than 12 hours, I set it for 12 hours, regardless of sunrise and sunset. I have no scientific proof, but I feel like the shorter daylight periods (together with a drop in temp) helps the phals and paphs spike.

-J

Looks like I need to change the setting on my timer. I keep mine on for around 16 hours. The plants seem to do okay. Plenty of new growth and flower spikes are fairly regular, I assume. I am still new to this so flowering times are still a little hazy to me.

Sixteen hours should not be a problem, Amanda. I run mine from 12-16 hours (less in the winter). I don't know if the change really helps, but do know that a lot of plants are daylight sensitive. I've seen articles advocating up to 18 hours of light.

Would the 16 - 18 hours of usage be needed because the wavelength from the bulbs is not as good as natural daylight wavelength?