Question
Sorry in advance as this is a How to question, but I cannot find an answer.

I have a small indoor greenhouse I use for tropical plants and seedlings.  I know it is recommended to use 12 hours of light in the winter months (Fall and winter) and 14-16 hours for the growing season. (Spring, summer)  My question is this; Do I need to gradually add or take away time from my timer throughout the year, or can I simply cut the hours back in one fell swoop when the solstice hits?  (This year I did one fell swoop as I have a cheep timer with 30 minute interval tabs and my yearly timing was a bit askew)

Thanks,
Ed

Answer
You can do make the change suddenly.  It'll actually take a several weeks for the hormonal changes to occur in response to the change in light.  We change our light system all at once at our nursery.  Besides, the ambient light from windows and such will temper the sudden change in your artificial lights.

Good growing!
Jacob Farin