My Ficus bonsai is showing leaf discoloration and brown spots; please help.

[HelpFicusPLS]

I’ve had it for 6 years and it has never had leaf loss this bad. Only started fertilizing end of last year (oops). Last repotted a year ago (can’t find any proper soil so I’m stuck with peat moss and garden soil). I water whenever soil is dry an inch or two in, and haven’t had serious problems with the plant since I got it (had two emergency travels for ~1 week in my 2nd and 3rd years of owning it, and it lost a whole lot of leaves then because 40-50°C summers. If any more info is needed let me know please.

 

[Silentrunning]

There are a couple of things Ficus plants hate. First is cold weather, anything below 45F. Second is moving. There are other things, but these are the major problems. I have about a dozen different Ficus and every winter they look like they are at deaths door. Once summer comes and they go back outside they are fine.

 

[HelpFicusPLS]

Thank you