I live in the US, midwestern area. Tree is always inside facing ESE window. I have the AC turned off in that room so it's pretty warm (compared to the rest of the house that is).

There are as many different opinions on fertilizer, it seems. A guy I know grows tremendous trees says it really doesn't matter too much what you use as long as you follow package directions. He says that the flushing type watering we do removes the excess, unused portion. I tend to follow his advice, and have no problems to report.

There are many specialty fertilizers and techniques out there that I think us novices need not worry about.

ez

Here's the new set-up. Humidity tray, removed the gravel on top and have pruned a bit. Would it be appropriate to fertilize now? I have definitely seen a decrease in yellow/dropping leaves but also have not seen much new growth.

Think of fertilizer like you would vitamins. You can go a while without. If plants look sick, shocky, or you're just unsure if actively growing, you can just wait and see.

ez