Too much fluorescent light?

[Ray]

I don't think UV is too much of a problem, but burning can be from direct heating, or from excessive heating of the plant tissues by exposure to to much light intensity. Leaf tissue can only dissipate the heat at a certain rate, so if the temperature and light intensity together are greater than what can be dumped, it's "scorch city!"

Some plants simply won't bloom well if exposed to too much light. Some of the best phalaenopsis plants I have ever seen were grown in almost complete darkness in an algae covered greenhouse.