Hi everyone, I’m Judy and I just joined this community tonight. My Corn plants leaves are turning yellow and brown. I do not over water. I check all of my plants twice a week to see if any need water and daily for pests. I have not seen any sign of pests and I only water once it has dried from the previous watering. It is winter so I have been spritzing it almost daily and it has a pebble tray to help with humidity. It in a good well draining soil. It has new growth. Our temps in the house at night and throughout the day are never below 65-70 degrees. I appreciate any help!
If these are all lower leaves (not certain about that last photo), that is not a problem. Old leaves will die; there is nothing you can do about that. New leaves come at the top, old old leaves die from the bottom. I wonder about sunburn in that last photo. Are you spraying with water when the sun is shining on the leaves?
The idea that water lying on leaves causes sunburn on a sunny day has been relegated to mythology. There are many websites that explain why it is not a problem, among which are: https://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-8137.2009.03150.x (very detailed) Can water burn plant leaves? (succinct) Judging from your pictures, I would say your cornflower plants look healthy and agree with Wendy that what, at first glance, may seem to be a problem is just normal leaf senescence. You certainly are taking very good care of your plants and obviously know what you are doing.
Here's another article supporting this conclusion: The Myth of Hot-Weather Watering. This is one of many horticultural myths Linda Chalker-Scott has prepared a writeup for.
I do mist my Corn Plant pretty much daily, but it is several feet away from a north facing window. It gets light most of the day , but not direct sun.
