Leaves turned brown overnight ?

The pics are of a 6 week old white widow that, as of last night, looked perfectly healthy. This morning 1 of 4 plants had this problem. It wasn't the leaves nearest the light. The browning to a particular leaf is complete around the edge of the leaf and seems to move in towards the stem.Any suggestions greatly appreciated. Will forward bigger picture if will help.






Jack

Looks kinda like heat stress. Do you foliar feed? Or did you mist your plants at all. Maybe some nutes dropped on the leaves if you arent foliar feeding?

edit: can you do an above shot of the leaves? Or maybe a shot of more of that plant?

think you answered it yourself. closet to light??.......looks like it touched light