Full Spectrum LED's - Time per Day
 

I have been keeping my collection inside, while I work on shade houses. I keep it under full spectrum led's. Is it disruptive to the plant to have them on constantly, or is it possible they tolerate and actually benefit by spurred growth? And does that have something to do with whether the orchid is in spike? I am guessing it might be an issue, but I'd like to be certain.

And on that note, if constant light isn't advisable, is there any benefit to using the lights for a maximum acceptable time per day? And if so, what would that maximum be?

Otherwise, what's the best schedule? Should I try to follow the natural rhythms of the daylight and nighttime where I live? Or otherwise, is a certain maximum, or on all the time okay? (and which schedule is most advisable and beneficial for the plants' growth?)

:thanx:

For most plants, some duration of darkness is necessary for physiological processes just like humans need sleep. CAM plants in particular (Phals, and others) only absorb CO2 at night for instance.

I think most people keep their lights on for 12 hours or so, as this is the daylength in the tropics close to the equator. Some orchids are indeed photoperiod responsive for blooming, but as this seems to be a very temporary solution for you until the plants move outside, I wouldn't be too concerned about it.

I use lights as a supplemental light source so chose to have them on only 9-10 hours a day.

As far as intensity is concerned, if you have a plant that has a maximum exposure level of “X” foot-candles or lux, they lights should provide 50%-55% of that. This article explains why.

With modern horticultural LEDs you have to be careful regarding the total photon exposure per day. While LEDs can not burn plants the way the sun can (heat and UV scorching), exceeding the plants' photon tolerance will result in chlorosis and stress. In my experience this is especially likely to happen if indoor temperatures are on the low side.

I bought digital "smart outlets" from Kasa and have the lights set to turn on and off with sunset and sunrise. They were surprisingly cheap, around $8 each. I entered my location and it accesses the sunrise and sunset times so every day they are updated daily and I don't have to mess with them. I have no idea if it works but my idea was that giving them a more natural seasonal light pattern would support any flowering or growth patterns that are associated with the seasons. Though I do know most orchids are from the tropics where summer/winter differences in light are much smaller. The second advantage is that the bright LEDs which are on my windowsills as supplemental light don't blind me after dark in the winter.

In Philadelphia you're so far north your spring and fall days are shorter than ideal. You will have better flowering with a 12 hour day from spring to late fall. Some people use 12 hours year round, and others use 10-11 hours in winter.

Some plants (such as many Catts) won't bloom with any light at all at night (even a street light can be disruptive for some) When I was growing Phals in my spare bedroom in early orchid days, I found that supplementing natural light with cheap fluorescents (this before LEDs were available) 12 hours a day gave very enhanced blooming success.