If I recall, this soil is kept moist. which means things will slowly flow, like a nutrient or salt or a percipitant of some kind. This could just be build up of something. Though, again, I think these are kept moist, this could be a mold. I'm sure this doens't help at all and it sucks to have $80 worth of soil get tossed out.
But at the end of the day, you won't know there's really an issue until it's too late if you do use this soil. This all said, I don't use a lot of soil and when I do it gets used up pretty quickly so I don't deal with storing it. Hopefully someone with those experiences will be by shortly.
But at the end of the day, you won't know there's really an issue until it's too late if you do use this soil. This all said, I don't use a lot of soil and when I do it gets used up pretty quickly so I don't deal with storing it. Hopefully someone with those experiences will be by shortly.