Hello knowledgeable bosaiers.
I just got my plan a month/two ago, and it was wonderfully green and healthy. now it has started to loose leaves, and I believe that I might have overwatered it at one point, because the soil seemed to never dry, even a couple of days after it felt humid. the soil is back to normal now, but the leaves keep on dropping. some leaves drop even if they are being perfectly green and look healthy. I moved it to the window (to receive the few sunhours we have here in Scandinavia now) in hopes of helping. Today I noticed that it has some sort of snowy crystals on the visible roots! I wonder if this is a disease or just because the window might be too cold for the plant. I'll attach a photo below. very grateful for all your help. I will read through your bonsai tree-care articles and try to be a more conscious bonsai-carer further on.