Rock is right to say that plants "limp along" indoors during winter, unless you are willing and able to set up a system that provides adequate light and humidity. For some people, that's not worth it; for others, it is. I grew up on the equator, where there is green outside all year round. Keeping tropicals
literally makes me easier to live with in winter. (Ask my wife and daughter!)
My own basement setup cost me less than $200, and lets me keep a nice little collection of tropicals. I can keep the humidity high enough that
Ficus and
Schefflera start throwing aerial roots, and the light level is good enough, as long as I remember to change out the fluorescent bulbs on a timely basis. (If I don't, I start seeing enlarged leaves and elongated internodes.)
The best way to tell you more about my "Bonsai Crate" is with this link:
http://bonsaivaultforum.freeforums.org/the-bonsai-crate-t805.html. (Yes, shhh, it's to another forum; but Nut has been gracious about it before!) The sort of setup I have may not be practical for you; but hopefully you will at least get some ideas and principles from my project.
And, getting back to your original question: I fertilize my tropicals during the winter, but at about half the rate I use in summer. That's because fluorescents, even when changed out properly, can't match the power of sunlight. With less light energy, the trees can't make use of the same amount of nutrients.
Another site you will find very helpful, I think, is Jerry Meislik's. Dr. Meislik has been growing tropicals for decades, first in MI and now in Montana. Check him out at
www.bonsaihunk.us. (Yes, his username is tongue-in-cheek.)
