I feel so sad because just a week ago my cactus was doing so well...my mammillaria has begun to wilt. His spines are downcast and he's starting to lean a bit on one side. It's winter time and I water only once every 4 weeks, and he just got water 3 days ago. He sits in a temperature-regulated apartment near a south-facing window. Any thoughts on what I can do to make sure he doesn't wilt further/die?
Note: the pot is deep but it is half filled entirely with rocks at the bottom so that it's not deeply full of soil. Soil is half mix of commercial succulent potting soil + gravel.
