Hi Larry,


Fluorescent lighting won't produce much over an average of 600fc at
12" from the tube*, and light intensity falls rapidly with more
distance.

My bulbs must really need replacing, I just took a couple of reading and
could not find any that even got close to 600 fc. You have to be careful
when people are talking light levels. When I say my greenhouse is shaded to
1800 fc that is based on a midday reading on a day without clouds. During
most of the day the light levels are climbing towards or receding from this
peak. In addition clouds rob a lot of sun. When we talk about a 600 fc
fluorescent light, it is providing a full 600 fc for a full 12 hours. I
guess there needs to be some sort of 'fcHour' measure to help compare the
two environments. I do know that if I shaded to 600 fc it would be too dark
to bloom phals although it is fine under fluorescent lighting. I also know
that much more than 1200 - 1500 fc under HPS and phals will start to show
signs of stress, but in the greenhouse this light level is close to ideal.

That depends on one's definition of 'high light.' I would
characterize high light as being in the 4,000 fc to 5,000 fc range.

Others would consider your light levels to be about '50% shade'. Both
characterizations are right but sound so very different.

Pat