Small black spots on stem?

I have some peculiar black dots showing up and I can’t seem to figure out what it is. Did I pick up a disease somewhere along the line?

Strain: LSD (clones)
PPM: 1500
pH: 6.2 (usually ~5.8)
Nutrient Line: mainly Gen Hydro/Botinicare

My water source for these to clones was the water from my dehumidifier which came out at 30ppm. I’m afraid I may have picked up a hitchhiker from the dehumidifier water?

I can’t quite tell if the mother has it or not. It’s a bit harder to see any dots on her at this point.

I’m hoping this is just me being a little too observant and that this is just something the plant does, but this is only my second grow and I’ve never done clones before so any help is appreciated, thank you!

1 Like

Looks like a fungus. Spring something or other. But you’re indoor. Definitely could’ve been something growing in dehumidifier. Would keep an eye on it for sure. Could be nothing as it doesn’t really look like spring black stem.


I agree… looks kinda’ like black spot (Alternaria)… use a foliar fungicide. Remember to only spray just before lights out. If it’s not fungus, it’s not going to hurt to spray the affected leaves and stems.


I bought a used dehumidifier. Thought I cleaned it well. First grow. Caused grey mold (bud rot) in soil which I fought for a bit. Lost half of two plants buds to it. Dehumidifier water goes down the drain for me now. Unless I buy a brand new one and take meticulous care of it.

Grey mold is like that. Spreads fast. But is easily stopped from spreading once you remove all carriers. ─=≡Σ(╯°□°)╯︵┻┻


I just wash mine out about once am onto with a mild bleach solution.

1 Like

I spoke with a local grower too and he suggested it might very well be a form of light burn or “shock” more so.

He claims he’s seen something similar happen and that the small burns on the leaf tips in the picture might even hint toward that.

He also claimed the light stress causes some cells to burst and the black is their scar tissue. This sounded slightly off from anything I’ve researched but it sounded rather convincing. Anyone else by chance have experience with that?

Anyway, I stopped using my dehumidifier water until I can get a better idea of what’s going on, I decided putting tap water conditioner into my city tap water might just be the lesser of two evils here unless I boiled the dehum water but I have a bad habbit of wanting good water right away, lol.