Possibly sick avocado tree?
Hi! I'm an amateur gardener(?) This is my first time growing anything really... I grew this guy out of a pit. It's been about 5 months, give or take. It's about 2 feet tall now. Since I don't know much about growing/planting I just used some Miracle grow moisture control potting mix. He's mostly an indoor plant, but I try to put him outside every now and then for some direct sunlight. Ever since he got "sick" I haven't been taking him outside. I feed him a little more than half a cup of water twice a week. He was doing really well, but he recently started getting brown spots on a lot of the leaves... Diagnosis?