I understand that living in Colorado isn't the ideal place to grow an avocado tree. I started one out of boredom and got attached to it now, haha.

It lives inside on top of my fridge since there is a skylight almost directly above it.

It looked pretty healthy a few weeks ago and since the leaves all turned brown and shriveled up and fell off. A new one just grew (as pictured) with 2 tiny ones on the way. But the bog one pictured below is starting to wilt already and it's only been fully developed for a few days.

I used Miracle Grow cactus and citrus potting soil. I water once a week as I'm scared to drown the roots. I'm about 6 months in. Any advice?