Deborah,

I keep my two fans running 24 hours a day. There are times it feels like a
hurracane in my Greenhouse but it does really help.

The plants get tougher too because of the natural air movement they have in
nature.

About the only time I turn the fans off is when I'm working out there on a
sunny day and I want it to be quiet or want to listen to music.

Good Luck ... I hope your plants can recover.

Gene