I'm hoping someone might be able to help with a problem with one of my ferns that I just can't seem to solve. The smaller, bottom fronds on my bird's nest fern are turning yellowish-white, almost translucent. It's situated near east and south facing windows, out of direct sunlight. The soil is kept moist (the crown is never watered) and is fairly free-draining. I mist the plant every fews days. New fronds are continuing to grow from the crown, and I don't see any evidence of insects. Does anyone have an idea what might be causing this? Any suggestions? Any help saving this lovely plant would be appreciated.