I had been using filtered water to water this calathea beauty star, watering whenever the top layer (about up to my first knuckle joint) was dry. That probably came out to once a week, maybe slightly more frequent (once every 5 days or so?). In between I’ve been misting it every ~2 days to keep the humidity up. It’s been stationed on our kitchen counter, about 10ft away from our south-facing windows but still in range of plenty natural light. It has been quite hot/humid here; some of the humidity I anticipate makes it into our apartment. 

I’ve had the plant for two months now, and for the first 1.5 months I’ve had no issues and it’s been thriving. But the last two weeks it’s started having problems. At first the rims/tips of its leaves started browning, crisping, and curling. I assumed that meant it needed more water so I watered it slightly more frequently and gave it a bit deeper of a soak, but always letting excess water drain.

I got back from a long weekend away and the leaves seem to be yellowing a lot more, but don’t feel crisp to the touch. I assume this means I overcorrected and need to water less but I’m not really sure. The top layer of soil (up my first knuckle) was already dry like a day or two after my most recent watering. Worried about root rot because I’ve killed several plants that way already, so assume my instincts trend towards overwatering as well.

Any advice would be appreciated. Hoping this guy isn’t past the point of saving yet.

Calathea beauty star - is it over- or underwatered?