I’m completely new to orchids. I was given this orchid about 7 months ago. It’s been doing fine. However last week one of the leaves started to turn yellow. As you can see from the pictures.
Is something wrong with it? Or is this normal shedding?
I'll agree with Dolly that it's probably not getting enough water, but I'm guessing that the roots are failing due to decomposition and compression of that potting medium, so they are suffocating.
The soft, plastic pot it's in is typical of mass-produced phalaenopsis from Taiwan, so I assume you have not repotted it since its purchase.
A plant that size should probably be in about a 6" pot, and you need a potting medium that will hold moisture while still providing lots of air flow around the roots.
Good point, Ray. Enlarging the picture, I totally agree, a repotting is in order. You can either use a medium bark or moss and a clay pot. If the former, soak the plant well and notice the weight. Then water when it becomes light, check often. If moss, water when the top is crunchy, but don't soak it. Pour the water on top so the moss doesn't compact. Enjoy your orchid, don't stress.