Never had this problem, but curious - does it just grow on cube because that stays moist / holds water longer, and gets the time to grow out? Or is there another reason that the rockwool grows it? I used rapid rooters my first time, but hydro store only had rockwool last time, so been using them. Just curious why the rockwool grows it but not the others. Thanks!Yep common wen people pour water on the CUBE!
Why my hydro top feeder is a waste of time.
Just cover it with some soil. It'll go black when it drys out.
In future , water around the earth, not the rockwool, or use jiffy pellets instead if you don't like the algae.
it's a rapid rooterWait... or is that even a rockwool cube?