Another picture.

Hi,

Thanks for providing so much initial info on your care of the tree. Here are some possible issues that I can see from your post.

Setting the tree 2-3 feet from a west-facing window in a low light (overcast) setting is probably too stressful for the tree. Retusa can handle low light situations fairly well, but a spot closer to the window that is south-facing (if possible) would be better. Otherwise, you could set it under a florescent light (preferably full-spectrum, high lumen)to boost its food-making ability.

Your substrate looks a little iffy. I can't tell if it's moss or potting soil, but it should really be in fast draining soil with larger particles. There is a lot of literature on the internet about bonsai substrate (especially for ficus). Either way, you need a soil that drains in 1 to 3 days. So your soil is either retaining too much moisture causing the roots to rot, or the soil is fine and you're not watering enough. You'll need to test the soil with either your finger and/or chopstick to determine when the tree should be watered. Never let your soil become totally dry, although ficus can tolerate drier soil (especially in the winter).

Don't worry about disturbing the leaves with mist. If they're going to fall off, then there's nothing you can do to stop it. New leaf buds are a good sign -- branch browning not so much. If the branches are dry and brittle, then they're dead and you can safely remove them.

You will need to consider buying some fertilizer of some sort in the near future. Trees should be fed (in general) monthly in the winter and every two weeks during the growing season. There are tons of inexpensive, easy to use fertilizers out there. Just keep that eventuality in mind if you intend on keeping the tree healthy in the long term.

The good news: ficus retusa can take a beating and bounce back fairly easy. Once you get a feel for the watering, feeding, and light situation, then the little guy should bounce back well.

Thanks a lot for the reply.

I have purchased a fluorescent light as I have no south facing windows at all in my house. I have also purchased some bonsai feed.

The soil does seem a little mossy, should I consider buying some more soil?

Thanks again for the reply.

I would definitely consider buying a well draining soil to repot in the summer only. If you repot now the tree may not take the stress of being transplanted.

Also, be easy with the fertilizer will your tree is stressed. Just provide it good light (check) and find a good watering routine. You should be good to go!

I bought a bonsai tree and it's winter it got cold now it doing bad