Q.Very Unhappy Prayer Plant
Hi! Over the last couple of weeks my maranta has started to lose leaves rapidly – some of them are brown and curling, some are turning yellow, and most of the plant just looks limp and dry even though the soil is moist. I\’ve also noticed a new white film on some of the leaves that I\’m worried might be a fungal infection of some kind. I generally water it every few days, letting it dry out somewhat between waterings but not completely. I\’ve also been misting it every day or two now that the weather is cold and dry. It lives on top of my dresser in a north-facing window. I\’ve had my prayer plant for more than two years and it\’s gone through a couple of rough patches, but I\’ve never seen it this unhappy before and I feel terrible for letting it get so bad. Given how crispy most of the plant looks, is it not getting enough water despite how moist the soil is? What can I do to help it?

Certified GKH Gardening Expert
I notice a few issues.
That plant needs a transplant as soon as possible. Fresh soil in a larger pot is going to be necessary to cure the issues. It looks like stress is causing it to take up water too quickly causing some edema.
After addressing this, you will notice improvement, but it looks like there may be a case of powdery mildew or other similar infection. Fungicides will typically correct the issue.
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm