Mandarin Orange bonsai in distress

[CC_86]

I have a Mandarin Orange bonsai tree I received in Feb. A couple days after I got it, it started to bloom. Recently all the leaves started to fall of it and the bark on some of the stems are hardening. The oranges have not ripened and one fell off this morning. I first thought I might have had the light too close and moved it further away and it kept getting worse. Then I thought I might have been over watering and stopped watering it and it continues to get worse. Does anyone have any advice or know what might be going on with it?
Thanks!

[CC_86]

[CC_86]

[meesh]

Citrus is tough to grow indoors. If you can meet most of the requirements then you could attain some success. They need very bright light, when in active growth they should be evenly moist but never WET, and they are acid lovers and very heavy feeders. A good quality rhododendron food and an iron supplement are needed. Insects also love citrus. In my experience cirtus drops yellow leaves when not watered enough. They drop green leaves when they are over watered and that is the most frequent killer.

[opabinia51]

To me it looks like your climate would not support moving this tree directly outside so, I will recommend a greenhouse.

the tree should also be pruned.

So, I would get your tree outside and into some sort of greenhouse structure to give it the proper temerature that it needs and give it some liquid seaweed fertilizer to promote growth of leaves. Also, prune some of the bare branches away.