Last year I had purchased a 6 ft Peruvian apple cactus and I was wondering if I could get some guidance on the plants current health.
I've attached a photo for reference. It has three plants coming up, two which look really healthy, ridges are plump and a darker green color. The tallest plant is looking a paler green, the ridges are thinner, almost look like they have been sucked of moisture, and are starting to wrinkle a bit. I love this plant so much so I want to do what's best to keep it healthy but I am not sure if I am over or under watering it or how best to remedy the issue.
Any help out be amazing. Thank you!!