Growing Ficus Salicaria under T5 lights for the winter

I have moved my small ficus bonsai together with some seedlings of wrightia religiosa inside for the winter and they are growing under 2 T5 light tubes.
Ficus has been casting its leaves although new ones are sprouting. Lately I have seen white mold only on the substrate of ficus.
I made some search on IBC and I have read here that the mold (sign of a fungus attack?) on the substrate surface is due to the wet condition and I wonder if this mold (and/or fungus) causes the leaves to be pale (not a vivid green color) and their ends becoming brown and fall off their stems?
Thank you!

It is likely the too-wet soil that is causing the leaf problem, Ficus do not want wet feet. The fungus is mrerly symptom of wet soil. Let your soil dry out between watering and see if that helps. FYI, you tee likely will survive the winter even if it loses all its leaves -- assuming you don't rot the roots.

Thank you, Jim.
I have two shallow trays with some water in them which evaporates naturally and maintain a humid environment. What would you suggest about it? Should I keep it or not?

I've never known humidity trays to be useful. (Except for growing mosquitoes.)