WTF? Stems turnin black...help.

Never had this problem before.....guess its called damping off, canker, or psylum (pretty sure Im spelling that wrong). But what the hell causes this shit?! I have heard that high humidity and overwatering are the main causes but my humidity is fine (50-60%) and Im not watering ANY more than I have in the past with great results. The blackening of the stems only occurs right at the base as the stem meets the soil, starts off kinda purple and then goes to black and moldy looking resulting in the eventual death of two of my girls so far. I sprayed with a real powerful product called physan 20 but dunno if its really gonna help or not. Anybody have any comments, suggestions, ideas? anything is appreciated...thank you!!

if it looks like this, it's Pythium Wilt (damping off) ... usually results from too-wet environment, frequently from pre-soaking seeds, and the wet paper-towel thing ... (Mother Nature doesn't do it that way, why do some of us ?) ... :D ... I have tried swabbing the stems, with H2O2, in an effort to stop the fungal growth, didn't seem to help ... let it dry out, as much as you can, but don't get too hopeful ... there may be a simple fix to this, but I don't know of it ... in this photo, this was the only seedling to suffer from it, in a group of 13 ... it's a true plant-killer :(

From what I understand, once it starts it's almost impossible to stop. If you're not overwatering, have normal humidity, etc., then there's a good chance that the fungus was already present in the soil you're using.

Zandor explains the ugly process really well in this thread: Damping Off.

thanks that damping off attatchment pretty much describes everything that is going on. Looks just like all of the pics that I have seen or read about on the net....unfortunately all of the info I can find says the same thing....the only cure is prevention in the first place....which is great but not very helpful in my situation lol. Got the clones from my pops and he is having the same problem (also his first time EVER dealing with it) and both he and I are at our wits end trying to figure out how the hell this happened in the first place. Thinking that something got messed up during the cloning phase when the cuttings were taken. Most of the plants are fine but all in all i will prolly lose about 6 or 7 the way things are lookin. :(