I just noticed that my philodendron birkin’s stem is browning. For a while its new leaves have had these brown lines on them, but now one of the leaves are about to break off. She’s been doing great after I mixed her soil with orchid bark, but now… I’m pretty new to plant parenting, and any help is much appreciated. I’m pretty sure this isn’t part of the issue, but I have some fungus gnats flying around that I want to get rid of. Oh, and that brown spec on one of the stems is just dirt btw.