Does anyone know what this is? It used to turn light green, then I thought that I killed it by covering the bases with foil so that no light could get to it (it's only white now, not green. So maybe it's just dead, whatever it is?)... But now I guess that I'm nervous that it could be something that could spread to the rest of the plant and harm it. In the last photo, there appears to possibly be some of that white stuff creeping up the stem, but I'm not sure.
what makes you so sure, and what should be done about it? are you sure it's not mold, fungi, or algae?
by the looks of it your hydro so it has moisture all the time and another sign was that it was green and when you covered all light it turned white and died.Was it slimy to the touch before you covered it? if so it was slime moss nothing to worry about.
I do hydro - DWC/RDWC with hydroton and I haven't seen this - or moss growing in my system - anywhere. Then again, I don't use any sort of rapid rooter or rock wool because they can cause issues in some systems. What does it feel like? If you're doing DWC, that plug should be well above any wet zone - if it isn't... It looks to me like a salt buildup - maybe from wicking up from below? Will it rinse off with some RO? Maybe it was light green before from algae?
He mentioned it was light green before he covered it with foil that in turn blocked the light and killed the algae/moss.
Moss thrives in indirect sunlight needs humid air/ areas thrives on porous material and good nutrients all in all i would say slime moss.if their isn't enough air flow it grows like crazy.