How Long to leave the lights on?

[Pokey49]

I have about 20 orchids in the northwest corner of my sun room which has windows on the north, east, west and two sky lights, but the light is low this time of year. we live in Oregon. I have decided to give them supplemental light during winter and have 5 grow lights shining on them starting today. I am still cogitating over which kind of bulb I should be using. Right now I have 5 50w incandescent grow lights going. Still researching if they of CFLs would be better, but my next questionis: how long to leave the lights on? My wife thinks I should turn them on mid day about noon and shut them off about 8pm. I was thinking to turn them on asbout 8am and off about 5-6pm? I have no idea how long these lights should be on and the best time of day to have them on. Any advice out there??

Paul

[drtd]

CFL would be a definite improvement. Preferably something labeled "Cool White" or "Daylight". I usually try and give my plants 12-14 hours of light throughout the day. This time of year it is hard to get that amount of light with windows alone. I would watch how much light you get throughout the day, and supplement the remaining time with lights. I am an early riser, so my lights usually come on for about 2 hours before the sun comes up, and then on again for about 4-5 hours after the sun goes down. You can adjust this period to suite your schedule, as long as the total exposure time is 12-14 hours including sunlight from the windows. I grow in an east window, and get direct sun for the first 3-4 hours in the morning and indirect until the sun goes down.

-Danny

[Pokey49]

Ok, I could come up with a schedule something like that, have them come on about 5, off about 8 back on about 5 and off at 8

[RJSquirrel]

I havent grown with lights in a few years but I let mine mimic the hours of light that was seasonal. More in summer less in winter. Growing indoors you dont have to do this.

The lights you get from your lamps is continuous. The sun during the day is not due to clouds, rain, smog etc etc.

soooo...

I would say 8 hours a day of continuous lighting indoors would be equal to a 12 to 14 hr day of sun from morning till night.

Your generating a lot of heat you need to displace with the lights burning overhead. Thats going to be a factor that the longer you burn them the warmer and warmer all the plants will become internally. More lights = more airflow and higher humidity..

Its like an orchid ballet

[gngrhill]

I try to mimic natural light as much as possible. Right now they come on at 7 am and off at 7pm In addition to what ever natural light they get. They have lots of windows, but it's been so overcast I don't know how much good they are getting from the sun

[Pokey49]

RJ & gngrhill: so it sounds like you have the lights on during the day when its daylight coming on about dawn, and have them going off about dusk??? My original thinking was to use the lights to "boost" the amount of light they get during the day since light is low and the day is shorter. Or should I only have them on before dawn fora few hours and on again after dark for just a few hours??

[Pokey49]

Ok I changed the bulbs in my fixture (5 heads) to LEDs 60W daylight, 800 lumens, 5000k. I have them coming on at 5a and off at 9a and then back on at 5p and off at 8p. Ok or not ok?

[Philipm]

Best way is to figure out you DLI.
I light meter would be the best, but this my help.
https://www.extension.purdue.edu/ext...O/HO-238-W.pdf
Also watch your plants they will let you know.

I was at 10-12 moles/day. Just lowered it to 8-10 on average by shorting the light period.
I grow only Phalaenopsis.

[Pokey49]

Thanks for the link. Will check it out. I have phals paphs milts and a lonely Angraecum under the lights all next to the west and north windows. Got two paphs one masd and one Phal under the skylight with no artificial lighting.