A question from a fellow grower;
I’m asking this scientifically and hypothetically of course.
Say a plant someone else attempted to grow outside got really rained on. Took off like a champ and looks amazing but one leaf has a dark spot on it. The other three are bright healthy green. That person probably in order to maintain a moist environment has a two liter pop bottle with the bottom cut off and sunk halfway down into excellent homemade compost which grows tomatoes, squash corn and every other food plant you can imagine. The pop bottle top is taken off so there is air exchange and the plastic is clear is plenty of sun hits his baby.
I would suspect some sort of mold and while that person I imagine hates chemical he would want to protect his baby.
I’ll also mention in this educational example its a hanging flower basket that is uncovered but I imagine doesnt get too much direct rain water. I’m thinking he/she is going to quickly dig out the oversoaked compost and replace with some very dry earth to act like a sponge so this over water situation goes away.