Hello,

I’m sorry to hear about your ferns. The most common causes of ferns going brown are due to low humidity, not enough water, soil conditions and sunlight.

Your fern damage is unusual in that it is only on one side of the frond. This could be due to the position of the plant. Does one side receive too much sunlight, causing that side to brown; is it near a hot air conditioner which could damage the frond; does it rub against a hot building; or could it have been sprayed by an herbicide that hit one side of the frond. In that case, the plant should be moved to a better location. Read about fern care here: https://ferngardening.com/why-has-my-fern-gone-brown/

With ferns, watering is a major concern so ensure that it is watered adequately.

Thank you for contacting Ask Extension.

could this be RUST? there was no spraying or heat near these ferns. Thankyou

Hello,

Rust disease on plants generally shows up as brown spots on the underside of leaves or in this case, fronds. This damage is so consistent it seems that it would be due to an environmental cause. However, I cannot tell what that cause could be from a picture. I suggest that you submit the picture and/or a sample to the MSU Plant and Pest Diagnostic Lab, at: https://www.canr.msu.edu/pestid/ for a more thorough diagnosis.

Good luck with your fern.