Gina1960 said: 24/7? Or is it variable?
This is the kind of humidity calathea need inside your house. Humidifier, enclosed space, cycling on and off 24/7 about every 30/45 minutes and they thrive
The humidity is around 70% during the day and drops to around 45-50% during the night.
I put all my dying/dead Calatheas and some other tropical plants inside a clear plastic box and then put an essential oil diffuser there (it is basically a small humidifier).
The picture was taken immediately after I turned the oil diffuser on. It became much more foggy after just 10 minutes. Hopefully this will revive some of my plants.
Thank you for the suggestion.
