Black Haze in a tight spaze

These three girls are all wilting and/or barely growing. I'd say over-watering except I've only been giving maybe a quart then waiting till the soil dries a little bit. Not too much tho. Could it be a nutrient problem already?

I'm having some sort of mold issue I think. I cant figure it out I havent seen anything that looked like this. I've Googled leaf symptoms and molds but nothing looks similar enough for me to say that's it for sure. Any help will be greatly appreciated!