About a month ago I though the orange tree was going to die on me. It had outgrown it's pot ages ago, was outside a little too late in the season, and had been too dry for too long. By the time it had been indoors a couple weeks it was dropping leaves and looking beat up.
So I got a much bigger pot, whacked off a bunch of the outer roots while transplanting it, boosted the new soil with compost and worm castings, and gave it a good soaking with water, liquid fish, kelp fertilizer, and even Effective Microbes.
And now? Wow! It's taking off, re-greened its leaves, and loaded with flower buds. Have you ever smelled orange blossoms? This may get to the point where it has to go back down to the basement under the grow lights if we find it too potent!