A lot of organic growers make a fungal mold like that deliberately in the latter part of flowering, as the plant switches over from bacteria to fugal produced nutrients.
I make it by putting a layer of peat moss in a bowl, and then spinkle some basalt rock dust over that, then mist with a spray bottle until damp.
Then cover the bowl only leaving a little gap to allow a little oxygen exchange in a warm place, within a few days a grey coloured fuzzy fungal mold will take over the surface.
Then when it’s covered the whole surface, you take half and put it in some cheese cloth and soak in a bucket of water with a little molasses in it, and aerate the mixture for a fungal tea.