SOIL HELP.. Strange green algae on top of soil..

[Afroman1]

First time grower freaked out this morning by strange algae like substance on top of my soil. Day 13 for my 2 autoflower seedlings which still look healthy despite this green shit on top of my soil! They were on plain water for the first 10 days then on day 11 I started giving Ionic Grow Nutes at 1/4 strength.. Wouldn't say I've over fed/watered.. So where has this came from?! is it harmful to my girls?

 

[Qwertywill]

It can be harmful if kept wet. Let the soil dry out before you water again. Its from the soil being too damp.

 

[Weed Pharma]

I've had green algrea before on a clone that was left too wet for too long after rooting. I simply rinsed/transplanted and it did fine.
I agree that you need to let the soil dry out completely, using the old adage-
If you are not sure if it needs watering- it doesn't!

 

[al70]

I've actually seen this on my coco before i started covering with clay stones, it never got outa hand with me, probably because i let the top of my coco dry a little between feeds, it should die off if you let the top inch dry out, goodluck.

 

[OlderNOTwiser]

Not seen this on my cannabis plants but on many other potted plants. Letting it dry is part of the solution. Take a stick or something and scratch the surface of the soil just a bit. It lets air in and under the mold/fungus and will dry both it and the soil quicker. Just don't go nuts rooting around in there with the stick!