Several leaves of my Peace Lily are turning brown directly, or after first turning yellow. I'm pretty confident I'm watering it the right amount, but the hot weather started here in Madrid about 10 days ago, and I haven't humidified the leaves in the last few days. The problem started while I was humidifying it regularly, but it has worsened quickly since the weather got warmer. Should I humidify it every day? Would more than once a day be better? Is the humidity even that important, or could another issue be causing the problem?
It doesn't look like it needs to be repotted, and it's not receiving direct sunlight. Since my room is very hot, do I need to move it to a different room? I hope not, since it's where I spend my time working!
Also, some weeks ago I put some fertilizer in water and used that to water it 3 or 4 times in a row over a period of about 16 days. It was growing nicely, but then the problem started. Was that a bad idea? Could it be related to its present state?
How can I keep Peace Lily alive and growing?
Adding pics of roots in case there's anything wrong with them or the soil...